WO2020078043A1 - 一种确定组播流的df的方法、设备及系统 - Google Patents

一种确定组播流的df的方法、设备及系统 Download PDF

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Publication number
WO2020078043A1
WO2020078043A1 PCT/CN2019/094198 CN2019094198W WO2020078043A1 WO 2020078043 A1 WO2020078043 A1 WO 2020078043A1 CN 2019094198 W CN2019094198 W CN 2019094198W WO 2020078043 A1 WO2020078043 A1 WO 2020078043A1
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Prior art keywords
multicast
ratio
bandwidth
link
ethernet
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PCT/CN2019/094198
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English (en)
French (fr)
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刘毅松
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华为技术有限公司
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Priority to EP19873924.5A priority Critical patent/EP3866408A4/en
Publication of WO2020078043A1 publication Critical patent/WO2020078043A1/zh
Priority to US17/234,407 priority patent/US11546267B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H04L47/2483—Traffic characterised by specific attributes, e.g. priority or QoS involving identification of individual flows
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4641—Virtual LANs, VLANs, e.g. virtual private networks [VPN]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/16—Multipoint routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/38—Flow based routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/12—Avoiding congestion; Recovering from congestion
    • H04L47/125—Avoiding congestion; Recovering from congestion by balancing the load, e.g. traffic engineering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/33—Flow control; Congestion control using forward notification
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/76—Admission control; Resource allocation using dynamic resource allocation, e.g. in-call renegotiation requested by the user or requested by the network in response to changing network conditions
    • H04L47/762—Admission control; Resource allocation using dynamic resource allocation, e.g. in-call renegotiation requested by the user or requested by the network in response to changing network conditions triggered by the network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/78—Architectures of resource allocation
    • H04L47/781—Centralised allocation of resources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/80—Actions related to the user profile or the type of traffic
    • H04L47/806—Broadcast or multicast traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/82—Miscellaneous aspects
    • H04L47/822—Collecting or measuring resource availability data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
    • H04L2012/4629—LAN interconnection over a backbone network, e.g. Internet, Frame Relay using multilayer switching, e.g. layer 3 switching
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/74—Address processing for routing
    • H04L45/745—Address table lookup; Address filtering
    • H04L45/7453—Address table lookup; Address filtering using hashing

Definitions

  • the present application relates to the field of communication technology, and in particular, to a method, device, and system for determining the DF of a multicast stream.
  • Multicast is a method that uses a multicast address to send data to multiple devices on the transmission control protocol (TCP) / Internet protocol (IP) network in an efficient manner at the same time.
  • the multicast source sends a multicast stream to members of the multicast group in the multicast group via a link in the network, and all members of the multicast group in the multicast group can receive the multicast stream.
  • the multicast transmission method realizes point-to-multipoint data connection between the multicast source and members of the multicast group.
  • the multicast stream only needs to be transmitted once on each network link, and the multicast stream will be copied only when there is a branch in the link. Therefore, the multicast transmission method improves the data transmission efficiency and reduces the possibility of backbone network congestion.
  • Ethernet virtual private network (Ethernet virtual private network, EVPN) is a two-layer virtual private network (virtual private network, VPN) technology. EVPN connects customer sites (customer sites) in different regions through a cross-Internet protocol (IP) / multiprotocol label switching (MPLS) bearer network, which is equivalent to these customer sites being located in the same local area network (local area) network, LAN).
  • IP Internet protocol
  • MPLS multiprotocol label switching
  • a customer edge (CE) device can receive multicast streams from remote multicast sources via multiple operator edge (PE) devices.
  • the CE device is connected to the multiple PE devices through multiple Ethernet links, and the multiple Ethernet links belong to the same Ethernet segment (ES).
  • a designated forwarder (DF) election mechanism is introduced into EVPN.
  • the multiple PE devices elect DF based on a hash algorithm.
  • the hash-based DF election mechanism may cause overload of some Ethernet links in the multiple Ethernet links and insufficient bandwidth utilization of some Ethernet links in the multiple Ethernet links, As a result, the load sharing performance decreases.
  • the embodiments of the present application provide a method, device and system for determining the DF of a multicast stream.
  • the PE device determines the multicast stream according to the bandwidth occupancy of multiple Ethernet links belonging to the same ES
  • the DF thereby, helps to improve the balance of load sharing for transmitting multicast streams in EVPN.
  • a method for determining the DF of a multicast stream is provided, characterized in that the method is applied in an Ethernet virtual private network EVPN, which includes a first PE device, a second PE device and a CE device .
  • the CE device is connected to the first PE device via a first Ethernet link
  • the CE device is connected to the second PE device via a second Ethernet link
  • the first Ethernet link and the The second Ethernet link belongs to the same ES.
  • the method includes that the first PE device receives a first join message, and the first join message is used to instruct the CE device to request to join the first multicast group receiving the first multicast stream.
  • the first multicast stream is a multicast stream transmitted by the multicast source of the EVPN to members of the multicast group in the first multicast group.
  • the first PE device joins the CE device to the first multicast group according to the first join message.
  • the first PE device determines whether the first ratio is smaller than the second ratio, where the first ratio is a ratio of a first allocated bandwidth and a first link bandwidth, and the first allocated bandwidth indicates the first The allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the Ethernet link, and the first link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the first Ethernet link, and the first The second ratio is the ratio of the second allocated bandwidth to the second link bandwidth.
  • the second allocated bandwidth indicates the allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the second Ethernet link.
  • the second link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the second Ethernet link.
  • the PE device determines how many ESs the Ethernet link belongs to The bandwidth occupancy of an Ethernet link. Then, the PE device determines the PE device corresponding to the Ethernet link with the least occupied multicast stream bandwidth as the DF of the multicast stream according to the multicast stream bandwidth occupancy of the multiple Ethernet links. Therefore, it helps to improve the balance of load sharing for transmitting multicast streams in EVPN.
  • the EVPN further includes a third PE device, the CE device is connected to the third PE device via a third Ethernet link, and the third Ethernet chain The road belongs to the ES.
  • the method further includes that the first PE device determines that the first ratio is less than the third ratio, where the third ratio is the third allocation Ratio of bandwidth to third link bandwidth, the third allocated bandwidth indicates the allocated bandwidth in the total bandwidth that can be allocated to the multicast service on the third Ethernet link, and the third link bandwidth indicates the The total bandwidth that can be allocated to the multicast service on the third Ethernet link.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is greater than the At the second ratio, the first PE device determines that the first PE device is a non-designated forwarder (non-designated forwarder, non-DF) of the first multicast stream. In response to the first PE device determining that the first PE device is a non-DF of the first multicast stream, the first PE device does not allocate bandwidth for the first multicast stream.
  • non-DF non-designated forwarder
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the At the second ratio, and when the first PE device determines that the value of the IP address of the first PE device is greater than the value of the IP address of the second PE device, the first PE device determines the first A PE device is the DF of the first multicast stream.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the At the second ratio, and when the first PE device determines that the first link bandwidth is greater than the second link bandwidth, the first PE device determines that the first PE device is the first DF for multicast streaming.
  • the method further includes: when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the At the second ratio, the first PE device determines that the first PE device is the DF of the first multicast stream according to the Hash algorithm.
  • the method before the first PE device determines whether the first ratio is less than the second ratio, the method further includes that the first PE device receives the second PE A second Ethernet segment route sent by the device, where the second Ethernet segment route includes a second link bandwidth extension community attribute, and the second link bandwidth extension community attribute is used to carry the second link bandwidth.
  • the first PE device sends a first Ethernet segment route to the second PE device, the first Ethernet segment route includes a first link bandwidth extension community attribute, and the first link bandwidth extension community attribute is used To carry the first link bandwidth.
  • the PE device can automatically obtain the link bandwidth of all Ethernet links included in the ES.
  • the first join message is a multicast group join message sent by the CE device.
  • the method further includes that the first PE device sends a first join synchronization route to the second PE device, and the first join synchronization route is used to indicate The CE device requests to join the first multicast group receiving the first multicast stream.
  • the first joining synchronization route includes a first multicast DF extended community attribute, and the first multicast DF extended community attribute is carried as the first multicast stream The IP address of the DF's PE device.
  • the first join message is a second join synchronization route sent by the second PE device.
  • the method further includes that the first PE device automatically discovers the route per Ethernet segment based on the received first Ethernet from the third PE device A revocation message, determining that the third Ethernet link exits the ES, wherein the revocation message instructs the third PE device to revoke the first Ethernet and automatically discover a route per Ethernet segment.
  • the first PE device is based on the first link bandwidth and the second link bandwidth, or the first PE device is based on the value of the IP address of the first PE device and the second PE device's
  • the value of the IP address determines the PE device that is the DF of the second multicast stream, where the DF of the second multicast stream is the third PE before the third Ethernet link exits the ES Device, the second multicast stream is a multicast stream transmitted by the EVPN multicast source to members of the multicast group in the second multicast group, and the CE device is a group in the second multicast group Members of the broadcast group.
  • the first PE device sends a third join synchronization route corresponding to the second multicast stream to the second PE device, the third join synchronization route includes a second multicast DF extended community attribute, and the second The multicast DF extended community attribute carries the IP address of the PE device that is the DF of the second multicast stream.
  • the multicast stream on the Ethernet link exiting the ES can be transferred to other Ethernet links in time to ensure that the forwarding of the multicast stream is not interrupted .
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is greater than the At the second ratio, the first PE device determines that the first PE device is a non-DF of the first multicast stream. In response to the first PE device determining that the first PE device is a non-DF of the first multicast stream, the first PE device does not allocate bandwidth for the first multicast stream. The first PE device automatically discovers the route of each Ethernet segment according to the received second Ethernet from the fourth PE device, determines that a fourth Ethernet link joins the ES, and the CE device passes the first Four Ethernet links are connected to the fourth PE device.
  • the first PE device changes the PE device that is the DF of the third multicast stream from the first PE device to the fourth PE device, and the third multicast stream is the multicast source direction of the EVPN
  • the CE device is a multicast group member in the third multicast group.
  • the first PE device sends a fourth join synchronization route corresponding to the third multicast stream to the second PE device and the fourth PE device, where the fourth join synchronization route includes a third multicast DF extension Community attribute, the third multicast DF extended community attribute carries the IP address of the fourth PE device.
  • the multicast stream on the Ethernet link with a higher bandwidth occupancy rate in the ES can be migrated to the new Ethernet link, thereby improving each of the ES The balance of the Ethernet link.
  • a first PE device having a function to implement the behavior of the first PE device in the above method.
  • the function may be implemented based on hardware, or may be implemented based on hardware by executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the above functions.
  • the structure of the first PE device includes a processor and an interface, and the processor is configured to support the first PE device to perform the corresponding function in the foregoing method.
  • the interface is used to support the communication between the first PE device and the second network device or the end device or the listening device, and send the information involved in the above method to the second network device or the end device or the listening device or Instruction, or receive the information or instruction involved in the above method from the second network device or the calling end device or the listening end device.
  • the first PE device may further include a memory for coupling with a processor, which stores necessary program instructions and data of the first PE device.
  • the first PE device includes: a processor, a transmitter, a receiver, a random access memory, a read-only memory, and a bus.
  • the processor is respectively coupled to the transmitter, the receiver, the random access memory and the read-only memory through the bus.
  • the basic input / output system solidified in the read-only memory or the bootloader boot system in the embedded system is used to start the system and guide the first PE device into a normal operating state.
  • the application program and the operating system are run in the random access memory, so that the processor executes the method in the first aspect or any possible implementation manner of the first aspect.
  • a first PE device in a third aspect, includes: a main control board and an interface board. Further, the first PE device may further include a switching network board. The first PE device is used to perform the method in the first aspect or any possible implementation manner of the first aspect. Specifically, the first PE device includes a module for performing the method in the first aspect or any possible implementation manner of the first aspect.
  • a first PE device includes a controller and a first forwarding sub-device.
  • the first forwarding sub-device includes: an interface board, and further, may also include a switching network board.
  • the first forwarding sub-device is used to perform the function of the interface board in the third aspect, and further, may also perform the function of the switching network board in the third aspect.
  • the controller includes a receiver, a processor, a transmitter, a random access memory, a read-only memory, and a bus. Among them, the processor is respectively coupled to the receiver, the transmitter, the random access memory and the read-only memory through the bus.
  • the controller when the controller needs to be operated, the basic input / output system solidified in the read-only memory or the bootloader boot system in the embedded system is used to start the system, and the controller is booted into a normal operating state. After the controller enters the normal operating state, the application program and the operating system are run in the random access memory, so that the processor performs the function of the main control board in the third aspect.
  • a computer storage medium for storing programs, codes, or instructions used by the above-mentioned first PE device, which can be completed when the processor or hardware device executes these programs, codes, or instructions.
  • the function or steps of the first PE network device is provided.
  • an EVPN system includes a first PE device, and the first PE device is the first PE device in the foregoing second aspect or third aspect or fourth aspect.
  • the PE device determines that the CE device connected to the Ethernet link joins the multicast group of the multicast stream. Then, the PE device determines the PE device corresponding to the Ethernet link with the least occupied multicast stream bandwidth as the DF of the multicast stream according to the multicast stream bandwidth occupancy of the multiple Ethernet links. Therefore, it helps to improve the balance of load sharing for transmitting multicast streams in EVPN.
  • FIG. 1 is a schematic structural diagram of an EVPN according to an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of another EVPN according to an embodiment of the present application.
  • FIG. 3 is a flowchart of a method for determining a DF of a multicast stream according to an embodiment of this application;
  • FIG. 4 is a schematic structural diagram of a first PE device according to an embodiment of this application.
  • FIG. 5 is a schematic diagram of a hardware structure of a first PE device according to an embodiment of this application.
  • FIG. 6 is a schematic diagram of a hardware structure of another first PE device according to an embodiment of the present application.
  • the EVPN technology involved in this application can be found in the Internet Engineering Task Force (English: Internet Engineering Task, Abbreviation: IETF) Request for Comments (English: Request For Comments, Abbreviation: RFC) 7432. It is generally incorporated by reference in this application.
  • FIG. 1 is a schematic structural diagram of an EVPN according to an embodiment of the present application.
  • the EVPN includes an access side and a network side.
  • the access side is used to receive a multicast stream from the network side, and the access side communicates with the network side through an IP network.
  • the IP network may be a metropolitan area network (metropolitan area network, MAN) or a data center (DC) network or a mobile bearer network (mobile bearer network) or a fixed network (fixed network).
  • the typical mobile bearer network is the Internet Protocol Radio Access Network (Internet Protocol access network, IP RAN).
  • the access side includes a CE device 11, a PE device 11, and a PE device 12.
  • the CE device 11 is connected to the PE device 11 via the Ethernet link 11 and the CE device 11 is connected to the PE device 12 via the Ethernet link 12, the Ethernet link 11 and the Ethernet link 12 belong to the same ES, as shown in FIG. ES01.
  • the CE device 11 is dual-homed to the PE device 11 and the PE device 12 via two Ethernet links.
  • the Ethernet segment identifier can be used to identify ES01. Taking FIG. 1 as an example, the ESI values of ES01 of the Ethernet link 11 and the Ethernet link 12 are the same value, and the value is a non-zero value.
  • ESI includes a type (Type) field and an ESI value field, where the Type field is used to indicate the ESI generation method.
  • the two commonly used generation methods are Type0 and Type1, where Type0 indicates that it is generated by manual configuration, and Type1 indicates that it is generated by the link aggregation control protocol (LACP) running between the PE device and the CE device, and the ESI value
  • LACP link aggregation control protocol
  • the value range of the field is 0 to 0xFF, where "0x" means hexadecimal.
  • the generation and setting of ES and ESI can refer to the description in Chapter 5 of RFC7432.
  • the PE device 11 is connected to the PE device 12 through an inter-frame link.
  • the PE device 11 and the PE device 12 may be routers or Layer 3 switches.
  • the CE device 11 may be a router or a switch or a host.
  • the PE device 11, the PE device 12 and the CE device 11 in the embodiment of the present application may be corresponding devices defined in RFC7432.
  • the CE device 11 is a router or a switch, one or more hosts can be connected.
  • the host may be a physical device or a virtual machine (virtual machine, VM).
  • PE device 11 and PE device 12 are a pair of border gateway protocol (BGP) peers (BGP peers).
  • BGP peer can also be called EVPN peer.
  • "a pair of BGP peers" can be understood as: one device is the BGP peer of another device.
  • the PE device 11 and the PE device 12 are a pair of BGP peers, it can be understood that the PE device 11 is the BGP peer of the PE device 12, or the PE device 12 is the BGP peer of the PE 11 device.
  • the BGP peer may also be called a BGP neighbor; correspondingly, the EVPN peer may also be called an EVPN neighbor.
  • BGP peers are used uniformly in subsequent embodiments.
  • the BGP peer is established through the OPEN message specified in BGP, and the established BGP peer is maintained through the KEEPALIVE message.
  • OPEN message and the KEEPALIVE message please refer to the relevant descriptions of IETF RFC2858 and IETF RFC1771.
  • route reflectors (English: route reflector, abbreviation: RR) can be deployed in the devices at both ends of the BGP peer, so that the RR can be used to complete the establishment of the BGP peer.
  • the network side includes PE equipment 21 and CE equipment 21.
  • the PE device 21 is connected to the CE device 21, and the PE device 21 communicates with the PE device 11 through the first communication link and the PE device 21 communicates with the PE device 12 through the second communication link.
  • FIG. 2 is a schematic structural diagram of another EVPN according to an embodiment of the present application.
  • the EVPN shown in FIG. 2 has a similar structure to the EVPN shown in FIG.
  • the EVPN structure shown in FIG. 2 can be understood as the EVPN obtained by adding the PE device 13 on the basis of the EVPN structure shown in FIG. 1. The difference between FIG. 2 and FIG. 1 will be described below, and the details of FIG. 2 and FIG. 1 will not be repeated.
  • the CE device 11 is connected to the PE device 13 via an Ethernet link 13, which belongs to ES01. Therefore, the Ethernet link 11, the Ethernet link 12, and the Ethernet 13 belong to the same ES. In this way, the CE device 11 is multi-homed to the PE device 11, the PE device 12, and the PE device 13 via three Ethernet links.
  • the PE device 13 is connected to the PE device 11 through an inter-frame link, and the PE device 13 is also connected to the PE device 12 through an inter-frame link.
  • the PE device 13 communicates with the PE device 21 through the third communication link.
  • any two PE devices among the PE device 11, the PE device 12, and the PE device 13 are a pair of BGP peers.
  • the PE device 11 and the PE device 12 are a pair of BGP peers
  • the PE device 11 and the PE device 13 are a pair of BGP peers
  • the PE device 12 and the PE device 13 are a pair of BGP peers.
  • the CE device 21 serves as a multicast source device that sends multicast streams, and the CE device 11 can serve as a multicast stream receiving device.
  • the CE device 21 sends the multicast stream 01
  • the PE device 21 is responsible for forwarding the multicast stream 01 to the IP network.
  • both PE device 11 and PE device 12 receive multicast stream 01. If the CE device 11 is a multicast group member in the multicast group corresponding to the multicast stream 01, the PE device 11 is used to forward the multicast stream 01 to the CE device 11 via the Ethernet link 11, and the PE device 12 is used to pass the Ethernet The link 12 forwards the multicast stream 01 to the CE device 11.
  • FIG. 1 the CE device 21 serves as a multicast source device that sends multicast streams
  • the CE device 11 can serve as a multicast stream receiving device.
  • the CE device 21 sends the multicast stream 01
  • the PE device 21 is responsible for forwarding the multicast stream 01 to the IP network.
  • both PE device 11 and PE device 12 receive multicast stream 01. If the CE device
  • the PE device 11, the PE device 12, and the PE device 13 all receive the multicast stream 01. If the CE device 11 is a multicast group member in the multicast group corresponding to the multicast stream 01, the PE device 11 is used to forward the multicast stream 01 to the CE device 11 via the Ethernet link 11, and the PE device 12 is used to pass the Ethernet The link 12 forwards the multicast stream 01 to the CE device 11 and the PE device 13 is used to forward the multicast stream 01 to the CE device 11 via the Ethernet link 13.
  • Ethernet link 11 and Ethernet link 12 belong to the same ES.
  • the PE device 11 is the DF of the multicast stream 01
  • the PE device 12 is the non-designated forwarder (non-designated forwarder, non-DF) of the multicast stream 01.
  • the PE device 11 as the DF of the multicast stream 01 is responsible for forwarding the multicast stream 01 to the CE device 11, and the PE device 12 as the non-DF of the multicast stream 01 does not forward the multicast stream 01 to the CE device 11.
  • the Ethernet link 11, the Ethernet link 12 and the Ethernet link 13 belong to the same ES.
  • a PE device connected to only one Ethernet link in the Ethernet links belonging to the same ES serves as the DF.
  • the PE device 11 is the DF of the multicast stream 01
  • the PE device 12 and the PE device 13 are the non-DF of the multicast stream 01.
  • the PE device 11 as the DF of the multicast stream 01 is responsible for forwarding the multicast stream 01 to the CE device 11, and the PE device 12 and the PE device 13 as the non-DF of the multicast stream 01 do not forward the multicast stream to the CE device 11. 01.
  • RFC 7432 In determining the implementation of DF for multicast streams, RFC 7432 provides a possible implementation. That is, based on the IP address of the PE device belonging to the same ES and the identifier of the virtual local area network (VLAN) identifier (ID), the DF and non-DF of the corresponding VLAN are elected and determined. For the specific implementation, please refer to the explanation and description of RFC 7432, which will not be repeated here.
  • VLAN virtual local area network
  • the PE device may determine the DF of the multicast stream based on the Highest Random Weight (HRW) algorithm, where the HRW algorithm is a type of Hash algorithm Method to realize.
  • HRW Highest Random Weight
  • the specific implementation can be found in the draft of the IETF working group draft-ietf-bess-evpn-df-election-framework-03 (Framework for EVPN Designated Forwarder Election Extensibility).
  • the contents of the working group draft draft-ietf-bess-evpn-df-election-framework-03 seem to be copied as a whole and are generally incorporated by reference in this application, which will not be repeated here.
  • the PE device may determine the DF of the multicast stream based on the extended HRW algorithm.
  • the specific implementation can be found in the draft of the IETF working group draft-sajassi-bess-evpn-per-mcast-flow-df-election-01 (Per Multicast Flow Designated Forwarder Election for EVPN).
  • the content of draft-sajassi-bess-evpn-per-mcast-flow-df-election-01 of the working group draft seems to be copied in its entirety and is generally incorporated by reference in this application. .
  • the DF election mechanism based on the Hash algorithm may cause some Ethernet links in the multiple Ethernet links to be overloaded and the multiple Ethernet links The bandwidth utilization of some Ethernet links is insufficient, resulting in reduced load sharing performance.
  • a multicast source of a total of 9 multicast streams is CE device 21, and CE device 11 serves as a multicast group member of each multicast stream.
  • the PE device 11 serves as the multicast streams G1-G7 and has a total of 7 DFs for the multicast streams; the PE device 12 serves as the multicast streams G8-G9 and has a total of 2 DFs for the multicast streams.
  • the required bandwidth of each multicast stream is 100 Mbps
  • the transmission bandwidth load of the Ethernet link 11 is 700 Mbps
  • the transmission bandwidth load of the Ethernet link 12 is 200 Mbps. Therefore, the Ethernet link 11 may cause congestion due to overload, and the Ethernet link 12 may cause insufficient bandwidth utilization of the Ethernet link.
  • Mbps means Mbit / s, which is megabits per second (megabit per second).
  • PE devices no longer rely on the DF election mechanism of the Hash algorithm.
  • the PE device determines the DF of the multicast stream according to the bandwidth occupancy of multiple Ethernet links belonging to the same ES. Helps improve the balance of load sharing for transmitting multicast streams in EVPN.
  • FIG. 3 is a flowchart of a method for determining a DF of a multicast stream according to an embodiment of this application.
  • the method shown in FIG. 2 can be applied to the EVPN shown in FIG. 1 or FIG. 2.
  • the EVPN includes a first PE device, a second PE device, and a CE device, the CE device is connected to the first PE device via a first Ethernet link, and the CE device is connected to all the devices via a second Ethernet link The second PE device is connected, and the first Ethernet link and the second Ethernet link belong to the same ES. 1 and 2, the first PE device is the PE device 11 in FIG. 1 or 2, the second PE device is the PE device 12 in FIG. 1 or 2, and the CE device is FIG. 1 Or the CE device 11 in FIG.
  • the first Ethernet link is the Ethernet link 11 in FIG. 1 or FIG. 2
  • the second Ethernet link is the Ethernet link in FIG. 1 or FIG. Way 12
  • the ES is ES01.
  • the method shown in FIG. 3 includes S101 to S104.
  • the first PE device receives a first join message, where the first join message is used to instruct the CE device to request to join a first multicast group that receives a first multicast stream.
  • the multicast stream is a multicast stream transmitted by the multicast source of the EVPN to members of the multicast group in the first multicast group.
  • the first PE device joins the CE device to the first multicast group according to the first join message.
  • the CE device 21 located on the EVPN network side can send the multicast stream to the EVPN access side through the IP network.
  • the CE device 21 is a multicast source on the EVPN network side.
  • the CE device 21 is a server of an operator that provides video services to users.
  • the CE device 21 sends the first multicast stream to the PE device 21.
  • the first multicast stream may be represented as (S1, G1), where S1 represents the multicast source IP address of the first multicast stream, that is, the IP address of the CE device 21; G1 represents the first multicast group ’s IP address.
  • the PE device 21 may forward the first multicast stream to the PE device 11 and the PE device 12 via the IP network.
  • the first multicast stream may reach the CE device 11 via the PE device 11 and the Ethernet link 11, or the first multicast stream may reach the CE device 11 via the PE device 12 and the Ethernet link 12.
  • the CE device 11 In order for the CE device 11 to receive the first multicast stream, the CE device 11 needs to request to join the first multicast group of the first multicast. Specifically, in a possible implementation manner, the CE device 11 sends the first multicast group join message to the PE device 11 via the Ethernet link 11.
  • the first multicast group join message is a first join message, and the first join message is used to instruct the CE device 11 to request to join the first multicast group that receives the first multicast stream.
  • the PE device 11 After receiving the first multicast group join message, the PE device 11 adds the CE device 11 to the first multicast group of the first multicast stream according to the first multicast group join message .
  • the PE device 11 can confirm that the CE device 11 becomes a member of the multicast group in the first multicast group, and the CE device 11 can receive the first multicast stream forwarded by the PE device 11 via the Ethernet link 11.
  • the PE device 11 After the PE device 11 receives the first multicast group join message, the PE device 11 generates a first join synchronization route (join synch route) according to the first multicast group join message, and the first join synchronization route It is used to instruct the CE device 11 to request to join the first multicast group receiving the first multicast stream.
  • the PE device 11 sends the first added synchronization route to the PE device 12.
  • the PE device 12 After receiving the first joining synchronization route, the PE device 12 adds the CE equipment 11 to the first multicast group of the first multicast stream according to the first joining synchronization route. In this way, the PE device 12 can confirm that the CE device 11 becomes a member of the multicast group in the first multicast group, and the CE device 11 can receive the first multicast stream forwarded by the PE device 12 via the Ethernet link 12.
  • the CE device 11 sends a second multicast group join message to the PE device 12 via the Ethernet link 12.
  • the PE device 12 adds the CE device 11 to the first multicast group of the first multicast stream according to the second multicast group join message .
  • the PE device 12 can confirm that the CE device 11 becomes a member of the multicast group in the first multicast group, and the CE device 11 can receive the first multicast stream forwarded by the PE device 12 via the Ethernet link 12.
  • the PE device 12 After the PE device 12 receives the second multicast group join message, the PE device 12 generates a second join synchronization route according to the second multicast group join message.
  • the second join synchronization route is the first join message, and the first join message is used to instruct the CE device 11 to request to join the first multicast group that receives the first multicast stream.
  • the PE device 12 sends the second added synchronization route to the PE device 11.
  • the PE device 11 adds the CE equipment 11 to the first multicast group of the first multicast stream according to the second joining synchronization route. In this way, the PE device 11 can confirm that the CE device 11 becomes a member of the multicast group in the first multicast group, and the CE device 11 can receive the first multicast stream forwarded by the PE device 11 via the Ethernet link 11.
  • the first multicast group join message and the second multicast group join message may be Internet Group Management Protocol (IGMP) messages.
  • the first joining synchronization route and the second joining synchronization route may be IGMP joining synchronization routes (IGMP join synch route).
  • the implementation method of adding IGMP to the synchronous route can be referred to IETF working group draft draft-ietf-bess-evpn-igmp-mld-proxy-02 (IGMP and MLD Proxy for EVPN).
  • the contents of the working group draft draft-ietf-bess-evpn-igmp-mld-proxy-02 seem to be copied as a whole and are generally incorporated by reference in this application, and will not be repeated here.
  • the first multicast group join message and the second multicast group join message may be protocol independent multicast (PIM) messages.
  • the first joining synchronization route and the second joining synchronization route may be PIM joining synchronization routes (PIM join synchronization route).
  • PIM join synchronization route the implementation of the PIM joining synchronous routing can be found in the IETF working group draft draft-skr-bess-evpn-pim-proxy-01 (PIM Proxy in EVPN Networks).
  • the contents of the working group draft draft-skr-bess-evpn-pim-proxy-01 seem to be copied as a whole and are generally incorporated by reference in this application, which will not be repeated here.
  • the foregoing uses FIG. 1 as an example to describe an implementation manner in which the CE device 11 joins the first multicast group of the first multicast stream.
  • the EVPN may include more than two PE devices connected to the CE device 11, for example, FIG. 3.
  • the CE device 11 may join the first multicast group of the first multicast stream according to the implementation manner described above. For example, the CE device 11 sends a multicast group join message to the PE device 11, and the PE device 11 announces to the PE device 12 and the PE device 13 that the synchronization route is added. Therefore, the PE device 11, the PE device 12, and the PE device 13 can all confirm that the CE device 11 joins the first multicast group of the first multicast stream.
  • the CE device 11 is taken as an example to describe a network device that receives a multicast stream.
  • an EVPN may include multiple CE devices 11, and each CE device 11 may implement the joining of a multicast group and the reception of multicast streams in the above manner.
  • the first multicast stream is used as an example for description. It should be understood that EVPN can transmit multiple multicast streams.
  • the CE device 11 joins the multicast group corresponding to each multicast stream, it can be implemented according to the above implementation manner.
  • the first PE device determines whether the first ratio is less than a second ratio, where the first ratio is a ratio of a first allocated bandwidth and a first link bandwidth, and the first allocated bandwidth indicates the first The allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the Ethernet link, and the first link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the first Ethernet link, and the first The second ratio is the ratio of the second allocated bandwidth to the second link bandwidth.
  • the second allocated bandwidth indicates the allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the second Ethernet link.
  • the second link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the second Ethernet link.
  • the first PE device determines that the first ratio is less than the second ratio, the first PE device determines that the first PE device is the DF of the first multicast stream.
  • the first PE device In response to the first PE device determining that the first PE device is the DF of the first multicast stream, the first PE device allocates bandwidth to the first multicast stream.
  • the CE device 11 may receive the first multicast stream forwarded by the PE device 11 via the Ethernet link 11, or the CE device 11 may receive the first multicast stream forwarded by the PE device 12 via the Ethernet link 12.
  • One multicast stream if the CE device 11 receives the first multicast stream from the PE device 11 and the PE device 12 at the same time, the traffic of the CE device 11 will be double-collected, resulting in a waste of network resources. Therefore, the DF election mechanism in EVPN will avoid this type of traffic double receipt.
  • the PE device 11 determines whether the PE device 11 is the DF of the first multicast stream, thereby determining whether the PE device 11 can forward the multicast message belonging to the first multicast stream to the CE device 11 via the Ethernet link 11 .
  • the PE device 12 determines whether the PE device 12 is the DF of the first multicast stream, thereby determining whether the PE device 12 can forward the group belonging to the first multicast stream to the CE device 11 via the Ethernet link 12 Broadcast message.
  • the following uses PE device 11 as an example to describe an implementation process in which PE device 11 determines the DF of the first multicast stream.
  • the PE device 11 Before performing S103, the PE device 11 needs to know the link bandwidth of all Ethernet links in ES01. As shown in FIG. 1, the PE device 11 needs to know the link bandwidth of the Ethernet link 11 and the Ethernet link 12 belonging to ES01. Since the PE device 11 is connected to the Ethernet link 11, the PE device 11 may determine the first link bandwidth of the Ethernet link 11. The first link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the Ethernet link 11, that is, the first link bandwidth is forwarded by the PE device 11 to the CE device 11 via the Ethernet link 11 The total bandwidth of the multicast service. Specifically, the PE device 11 may forward multiple types of services, such as unicast services, multicast services, and broadcast services, to the CE device 11 via the Ethernet link 11.
  • unicast services such as unicast services, multicast services, and broadcast services
  • the first link bandwidth refers to the allocatable bandwidth for the PE device 11 to forward the multicast service to the CE device 11 via the Ethernet link 11, that is, the PE device 11
  • the specific value of the first link bandwidth may be determined by the PE device 11 according to the forwarding capability of the line card of the PE device 11.
  • the forwarding capability of the line card of the PE device 11 is expressed as a bandwidth of 2000 Mbps, where 500 Mbps is allocated to unicast service use, 1000 Mbps is allocated to multicast service use, and 500 Mbps is allocated to broadcast service use, then 1000 Mbps is Describe the specific value of the first link bandwidth.
  • the specific value of the first link bandwidth may also be determined by the PE device 11 according to the physical bandwidth of the Ethernet link 11.
  • the physical bandwidth of the Ethernet link 11 is expressed as 2000 Mbps, where 500 Mbps is allocated for unicast service use, 1000 Mbps is allocated for multicast service use and 500 Mbps is allocated for broadcast service use, then 1000 Mbps is the first The specific value of a link bandwidth.
  • the PE device 12 can determine the second link bandwidth of the Ethernet link 12 through the above implementation manner, and the second link bandwidth instructs the PE device 12 to forward the multicast service to the CE device 11 via the Ethernet link 12
  • the bandwidth can be allocated, that is, the total bandwidth required for the PE device 12 to forward the multicast stream to the CE device 11 via the Ethernet link 12. Therefore, in the embodiments of the present application, the link bandwidth of the Ethernet link refers to the bandwidth used to forward the multicast service.
  • the PE device 11 also needs to know the second link bandwidth of the Ethernet link 12.
  • the PE device 11 may learn the second link bandwidth through static configuration. Specifically, the network administrator directly configures the link bandwidth of the Ethernet link included in ES01 in the PE device 11.
  • the EVPN may include a network management device that sends to the PE device 11 the link bandwidth of the Ethernet link included in ES01.
  • the PE device 11 receives the second Ethernet segment route sent by the PE device 12, the second Ethernet segment route includes a second link bandwidth extension community (link bandwidth extended community) attribute, The second link bandwidth extension community attribute is used to carry the second link bandwidth.
  • the PE device 11 can obtain the second link bandwidth according to the second Ethernet segment route.
  • the implementation of the second Ethernet segment routing can be found in the corresponding explanation in RFC 7432, and the implementation of the second link bandwidth extension community can be found in the draft of the IETF working group draft-ietf-idr-link-bandwidth -07 (BGP LinkBandwidthExtendedCommunity).
  • the content of the draft draft-ietf-idr-link-bandwidth-07 of the working group seems to be copied as a whole and is generally incorporated by reference in this application and will not be repeated here.
  • the PE device 11 may also send a first Ethernet segment route to the PE device 12, the first Ethernet segment route includes a first link bandwidth extension community attribute, and the first link bandwidth extension community attribute Carrying the first link bandwidth.
  • the PE device 12 may obtain the first link bandwidth according to the first Ethernet segment route.
  • the PE device 11 can obtain the link bandwidth of all Ethernet links included in ES01.
  • the PE device 12 can also obtain the link bandwidth of all Ethernet links included in ES01.
  • the PE device 11 may determine the first ratio and the first link bandwidth according to the first link bandwidth and the second link bandwidth The second ratio.
  • the first ratio is the ratio of the first allocated bandwidth to the first link bandwidth.
  • the first allocated bandwidth indicates the allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the Ethernet link 11.
  • a link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the Ethernet link 11
  • the second ratio is a ratio of the second allocated bandwidth to the second link bandwidth
  • the second allocated bandwidth indicates the Ethernet link
  • the second link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the Ethernet link 12.
  • the first allocated bandwidth refers to the bandwidth already allocated to the multicast service in the total bandwidth that can be allocated to the multicast service on the Ethernet link 11. For example, the value of the first link bandwidth is 1000 Mbps.
  • the DF of the multicast stream G1 and the multicast stream G2 is the PE device 11, and the multicast group corresponding to the multicast stream G1 includes the CE device 11 and the multicast group corresponding to the multicast stream G2 includes the CE device 11.
  • neither the multicast stream G1 nor the multicast stream G2 includes the aforementioned first multicast stream.
  • the bandwidth of the multicast service allocated by the PE device 11 for the multicast stream G1 is 100 Mbps
  • the bandwidth of the multicast service allocated by the PE device 11 for the multicast stream G2 is 200 Mbps. Therefore, in the above 1000Mbps, the allocated bandwidth is 300Mbps, and the remaining allocated bandwidth is 700Mbps.
  • the first ratio is the ratio of the sum of the required bandwidth of the multicast stream of the PE device 11 as the DF and the CE device 11 as the member of the multicast group to the bandwidth of the first link.
  • the second ratio is the ratio of the sum of the required bandwidth of the multicast stream of the PE device 12 as the DF and the CE device 11 as the member of the multicast group to the bandwidth of the second link.
  • the sum of the required bandwidths of the multicast streams with the PE device 11 as the DF and the CE device 11 as the multicast group member specifically refers to: the multicast streams corresponding to the multicast groups that the CE device 11 has joined, and these multicast streams
  • the PE device 11 is used as a DF to forward to the CE device 11, and the PE device 11 determines the sum of the required bandwidths of these multicast streams.
  • the sum of the required bandwidth of the multicast streams with the PE device 12 as the DF and the CE device 11 as the member of the multicast group specifically refers to the multicast streams corresponding to the multicast groups that the CE device 11 has joined, and these multicast streams are
  • the PE device 12 forwards to the CE device 11 as a DF, and the PE device 11 determines the sum of the required bandwidth of these multicast streams.
  • the "total required bandwidth of multicast streams" mentioned in the embodiments of the present application is equivalent to the "assigned bandwidth in the total bandwidth that can be allocated to multicast services" mentioned in the embodiments of the present application, the two are just The expression is different.
  • CE device 11 has joined the multicast group of multicast stream G1, the multicast group of multicast stream G2, the multicast group of multicast stream G3, and the multicast group of multicast stream G4, that is, The CE device 11 becomes a multicast group member of G1, a multicast group member of G2, a multicast group member of G3, and a multicast group member of G4.
  • the PE device 11 is a DF that forwards G1 and G2 to the CE device 11
  • the PE device 12 is a DF that forwards G3 and G4 to the CE device 11.
  • the required bandwidth for transmitting G1 is 100Mbps
  • the required bandwidth for transmitting G2 is 50Mbps
  • the required bandwidth for transmitting G3 is 150Mbps
  • the required bandwidth for transmitting G4 is 150Mbps.
  • the first link bandwidth is 2000 Mbps
  • the second link bandwidth is 1000 Mbps.
  • the PE device 11 determines whether the first ratio is smaller than the second ratio based on the calculated first ratio and second ratio. For example, the first ratio is 0.075 and the second ratio is 0.3. The PE device 11 determines that the first ratio is smaller than the second ratio, and thus, the PE device 11 determines that the PE device 11 is the DF of the first multicast stream. In addition, the PE device 11 also determines that the PE device 12 is a non-DF of the first multicast stream. The PE device 11 stores the entry information of the first multicast stream, and the PE device 11 marks the DF corresponding to the entry information of the first multicast stream as the PE device 11, and marks the first multicast stream The non-DF corresponding to the table entry information is marked as PE device 12.
  • the PE device 11 After the PE device 11 determines that the PE device 11 is the DF of the first multicast stream, the PE device 11 allocates the bandwidth of the multicast service to the first multicast stream. Correspondingly, the PE device 11 updates the value of the first allocated bandwidth. In this way, when the PE device 11 subsequently receives the multicast stream, it is possible to determine the value of the first ratio and the value of the second ratio according to the latest bandwidth occupancy.
  • the PE device 11 may also mark the PE device 11 according to the DF corresponding to the entry information of the first multicast stream, and forward the multicast message belonging to the first multicast stream to the CE device 11 via the Ethernet link 11 .
  • the PE device determines how many ESs the Ethernet link belongs to The bandwidth occupancy of an Ethernet link. Then, the PE device determines the PE device corresponding to the Ethernet link with the least occupied multicast stream bandwidth as the DF of the multicast stream according to the multicast stream bandwidth occupancy of the multiple Ethernet links. Therefore, it helps to improve the balance of load sharing for transmitting multicast streams in EVPN.
  • the implementation of the present application uses the PE device 11 as an example to illustrate an implementation manner in which the PE device connected to the Ethernet link in the ES determines the DF. In an actual scenario, all PE devices connected to the Ethernet link in the ES can implement the DF determination process according to the implementation of the PE device 11.
  • the EVPN further includes a third PE device, and the CE device is connected to the third PE device via a third Ethernet link, and the third Ethernet link belongs to the ES.
  • the method further includes: the first PE device determines that the first ratio is less than the third ratio, where the third ratio is the third allocated bandwidth and the third ratio Ratio of three link bandwidths, the third allocated bandwidth indicates the allocated bandwidth in the total bandwidth that can be allocated to the multicast service on the third Ethernet link, and the third link bandwidth indicates the third The total bandwidth that can be allocated to the multicast service on the Ethernet link.
  • FIG. 3 shows an embodiment in which an ES in an EVPN includes two Ethernet links. It should be understood that the implementation in FIG. 3 can be applied in a scenario where the ES includes more than two Ethernet links That is to say, the implementation of FIG. 3 can be applied in the scenario shown in FIG. 2.
  • the EVPN further includes a third PE device, the CE device is connected to the third PE device via a third Ethernet link, and the third Ethernet link belongs to the ES.
  • the third PE device is the PE device 13 in FIG. 2
  • the third Ethernet link is the Ethernet link 13 in FIG. 2.
  • the above features may be equivalent according to corresponding corresponding features.
  • the CE device 11 sends the first multicast group join message to the PE device 11 via the Ethernet link 11. After receiving the first multicast group join message, the PE device 11 adds the CE device 11 to the first multicast group of the first multicast stream according to the first multicast group join message . After the PE device 11 receives the first multicast group join message, the PE device 11 also sends the first join synchronization route to the PE device 13. After receiving the first joining synchronization route, the PE device 13 adds the CE equipment 11 to the first multicast group of the first multicast stream according to the first joining synchronization route.
  • the PE device 13 can confirm that the CE device 11 becomes a member of the multicast group in the first multicast group, and the CE device 11 can receive the first multicast stream forwarded by the PE device 13 via the Ethernet link 13.
  • the CE device 11 may also send a multicast group join message to the PE device 13 via the Ethernet link 13, and then the PE device 13 generates a corresponding group join message according to the multicast group join message. Join the synchronization route, and send the joining synchronization route to the PE device 11 and the PE device 12. Therefore, the PE device 11, the PE device 12, and the PE device 13 can all confirm that the CE device 11 joins the first multicast group of the first multicast stream.
  • the PE device 11 may acquire the third link bandwidth of the Ethernet link 13 according to the foregoing embodiment.
  • the third link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the Ethernet link 13, that is, the third link bandwidth indicates that the PE device 13 forwards to the CE device 11 via the Ethernet link 13 The total bandwidth of the multicast service.
  • the PE device 11 is determining the third ratio.
  • the third ratio is the ratio of the third allocated bandwidth to the third link bandwidth, and the third allocated bandwidth indicates the allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the Ethernet link 13.
  • the third ratio is the ratio of the sum of the required bandwidths of the multicast streams of the PE device 13 as the DF and the CE device 11 as the member of the multicast group to the third link bandwidth.
  • the PE device 11 determines the ratio corresponding to all the Ethernet links included in the ES01 (for example, the first ratio, the second ratio, and the third ratio in the foregoing), the PE device 11 determines all the Ethernet links The minimum ratio among the corresponding ratios, so that the PE device 11 can determine the DF responsible for forwarding the first multicast stream according to the determined minimum ratio.
  • the PE device 11 can arbitrarily take two ratios from the ratios corresponding to all Ethernet links for comparison, and obtain a smaller ratio.
  • the PE device 11 then takes out the ratio that does not participate in the comparison from the ratios corresponding to all the Ethernet links, and compares the ratio with a smaller ratio until the minimum ratio among the ratios corresponding to all the Ethernet links included in ES01 is obtained. As shown in FIG. 3, the PE device 11 first determines whether the first ratio is smaller than the third ratio. When the PE device 11 determines that the first ratio is less than the third ratio, the PE device 11 further determines whether the first ratio is less than the second ratio. If the PE device 11 determines that the first ratio is smaller than the second ratio, the PE device 11 may determine that the first ratio is the smallest ratio among the ratios corresponding to all Ethernet links included in ES01.
  • the PE device 11 serves as a DF that forwards the first multicast stream to the CE device 11.
  • the implementation manner of the PE device 11 determining that the first ratio is less than the third ratio can refer to the description of the foregoing implementation manners of this application, and details are not described here.
  • both the PE device 12 and the PE device 13 in FIG. 3 may determine the DF of the first multicast stream according to the implementation manner of the PE device 11.
  • the PE device 11 determines the PE device 11 as the DF of the first multicast stream, and determines the PE device 12 and the PE device 13 as the non-DF of the first multicast stream.
  • PE device 12 determines PE device 11 as the DF of the first multicast stream, and determines PE device 12 and PE device 13 as the non-DF of the first multicast stream;
  • PE device 13 determines the PE device 11 Determine the DF of the first multicast stream, and determine the PE device 12 and the PE device 13 as the non-DF of the first multicast stream.
  • the DF results determined by the PE device 11, the PE device 12, and the PE device 13 are consistent, thereby ensuring that the PE device 11 is responsible for forwarding the first multicast stream, and avoiding double-collection or excessive collection of traffic of the CE device 11.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is greater than the second ratio, the first PE The device determines that the first PE device is a non-DF of the first multicast stream. In response to the first PE device determining that the first PE device is a non-DF of the first multicast stream, the first PE device does not allocate bandwidth for the first multicast stream.
  • the PE device 11 determines the PE device 11 as the non-DF of the first multicast stream and the PE device 12 Determined as the DF of the first multicast stream.
  • the PE device 12 will also determine the PE device 11 as the non-DF of the first multicast stream and the PE device 12 as the DF of the first multicast stream according to the foregoing implementation manner. Therefore, the PE device 11 does not allocate bandwidth for the first multicast stream, that is to say, the PE device 11 is not used to forward multicast messages belonging to the first multicast stream to the CE device, the PE The device 12 is configured to forward the multicast message belonging to the first multicast stream to the CE device.
  • the PE device 11 since the PE device 11 determines the PE device 12 as the DF of the first multicast stream, the PE device 11 updates the value of the second allocated bandwidth stored by the PE device 11, so that the second allocated bandwidth The value includes the required bandwidth of the first multicast stream.
  • the PE device 11 determines the PE device 11 and the PE device 13 as the The non-DF of the first multicast stream and the DF that determines the PE device 12 as the first multicast stream. Accordingly, the results determined by the PE device 12 and the PE device 13 are consistent with the results determined by the PE device 11.
  • the PE device 11 is configured not to forward the multicast message belonging to the first multicast stream to the CE device.
  • the PE device 11 sends an announcement message to the PE device 21, where the announcement message indicates that the PE device 11 is the first Non-DF for multicast streaming.
  • the PE device 21 no longer forwards the multicast message of the first multicast stream to the PE device 11 according to the announcement message.
  • the PE device 11 continues to receive the multicast message of the first multicast stream forwarded by the PE device 21. After receiving the multicast message of the first multicast stream, the PE device 11 directly discards the multicast message of the first multicast stream, or waits for the multicast message of the first multicast stream to age Discarding.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the second ratio, and when the When the first PE device determines that the value of the IP address of the first PE device is greater than the value of the IP address of the second PE device, the first PE device determines that the first PE device is the first multicast For the DF of the stream, the first PE device is used to forward the multicast message belonging to the first multicast stream to the CE device via the first Ethernet link.
  • the PE device 11 further determines whether the value of the IP address of the PE device 11 is greater than the value of the IP address of the PE device 12.
  • the IP address of the PE device 11 and the IP address of the PE device 12 are the IP addresses used when establishing the BGP peer. Specifically, the device IP address of the PE device 11 and the device IP address of the PE device 12 may be used.
  • the PE device 11 determines that the PE device 11 is the DF of the first multicast stream, and the PE device 11 is responsible for forwarding to the CE device 11 Multicast messages of the first multicast stream.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the second ratio, and when the When the first PE device determines that the first link bandwidth is greater than the second link bandwidth, the first PE device determines that the first PE device is the DF of the first multicast stream, the first The PE device is configured to forward the multicast message belonging to the first multicast stream to the CE device via the first Ethernet link.
  • the PE device 11 further determines whether the first link bandwidth is greater than the second link bandwidth. When the first link bandwidth is greater than the second link bandwidth, the PE device 11 determines that the PE device 11 is the DF of the first multicast stream, and the PE device 11 is responsible for forwarding to the CE device 11 Multicast message of the first multicast stream.
  • the method further includes, when the first PE device determines that the first ratio is not less than the second ratio, and the first ratio is equal to the second ratio, the first PE The device determines that the first PE device is the DF of the first multicast stream according to the Hash algorithm, and the first PE device is configured to forward to the CE device via the first Ethernet link to belong to the first Multicast packets of the multicast stream.
  • the PE device 11 further determines the DF of the first multicast stream according to the Hash algorithm.
  • FIG. 2 uses FIG. 2 as an example to describe the implementation process of the embodiment of the present application.
  • the EVPN scenario shown in FIG. 2 includes multicast stream G1-multicast stream G9, for a total of 9 multicast streams.
  • the required bandwidth of the multicast stream G1-multicast stream G5 is 90Mbps
  • the required bandwidth of the multicast stream G6-multicast stream G9 is 150Mbps.
  • the multicast stream G1-multicast stream G9 can be transmitted from the network side of the EVPN shown in FIG. 2 to the access side of the EVPN.
  • the first link bandwidth is 1000Mbps
  • the second link bandwidth is 2000Mbps
  • the third link bandwidth is 1000Mbps.
  • the PE device 13 has the largest IP address.
  • the PE device 11, the PE device 12, and the PE device 13 can determine the DF of each multicast stream in sequence according to Table 1.
  • the PE device 11 executes the DF election process shown in Table 1 as an example for description. Furthermore, according to the foregoing embodiment, the PE device 11, the PE device 12, and the PE device have synchronized the first link bandwidth, the second link bandwidth, and the third link bandwidth with each other.
  • Multicast streaming First ratio Second ratio Third ratio Definite DF G1 0/1000 0/2000 0/1000 PE3 G2 0/1000 0/2000 90/1000 PE2 G7 0/1000 90/2000 90/1000 PE1 G8 150/1000 90/2000 90/1000 PE2 G3 150/1000 240/2000 90/1000 PE3 G6 150/1000 240/2000 180/1000 PE2 G5 150/1000 390/2000 180/1000 PE1 G4 240/1000 390/2000 180/1000 PE3 G9 240/1000 390/2000 270/1000 PE2 / 240/1000 540/2000 270/1000 /
  • the first column represents the multicast streams corresponding to the multicast groups that the CE device 11 sequentially joins;
  • the second column, the third column, and the fourth column respectively represent the first ratio determined according to the implementation method of the foregoing embodiment , The second ratio and the third ratio;
  • the fifth column represents the DF of the corresponding multicast stream determined by the PE device 11
  • the multicast stream G1 is the first multicast stream that the CE device 11 requests to receive. Therefore, the PE device 11 is used as the DF and the CE device 11 is used as the multicast group member. Demand bandwidth is always 0, the demand bandwidth of the multicast stream with PE device 12 as DF and CE device 11 as multicast group member is always 0, PE device 13 is used as DF and CE device 11 is used as multicast group member The required bandwidth of the multicast stream is always 0.
  • the PE device 11 determines that the first ratio, the second ratio, and the third ratio are equal to 0. Further, the PE device 11 determines that the value of the IP address of the PE device 13 is the largest. Thus, the PE device 11 determines that the PE device 13 is the DF of the multicast stream G1.
  • the CE device 11 joins the multicast group of the multicast stream G2.
  • the PE device 11 joins the multicast group of the multicast stream G2 according to the CE device 11, and re-determines the first ratio, the second ratio, and the third ratio.
  • the PE device 11 determines that both the first ratio and the second ratio are smaller than the third ratio, and the first ratio is equal to the second ratio. Further, the PE device 11 determines that the second link bandwidth is greater than the first link bandwidth. Thus, the PE device 11 determines that the PE device 12 is the DF of the multicast stream G2.
  • the CE device 11 joins the multicast group of the multicast stream G7.
  • the PE device 11 joins the multicast group of the multicast stream G7 according to the CE device 11, and re-determines the first ratio, the second ratio, and the third ratio.
  • the PE device 11 determines that the first ratio is the minimum ratio.
  • the PE device 11 determines that the PE device 11 is the DF of the multicast stream G7.
  • the multicast stream G8, the multicast stream G3, the multicast stream G6, the multicast stream G5, the multicast stream G4, and the multicast stream G9 in Table 1 can be successively subjected to DF election according to the above rules of this embodiment. No more details will be given here.
  • the last entry in Table 1 indicates that, after completing the DF election of the multicast stream G9, the PE device 11 stores the entry of the multicast stream G9 in the PE device 11 so that the CE device 11 can join the multicast stream in the future When multicasting a group, the first ratio, the second ratio, and the third ratio are newly determined.
  • the multicast streams transmitted by the Ethernet link 11 are the multicast stream G7 and the multicast stream G5, and the total required bandwidth of the multicast stream is 240 Mbps;
  • Ethernet The multicast streams transmitted by the network link 12 are the multicast stream G2, the multicast stream G8, the multicast stream G6, and the multicast stream G9, and the total required bandwidth of the multicast stream is 540 Mbps;
  • the Ethernet link 13 is responsible for the transmission group
  • the broadcast stream is the multicast stream G1, the multicast stream G3 and the multicast stream G4, and the total required bandwidth of the multicast stream is 270 Mbps.
  • the PE device 12 and the PE device 13 may also implement DF election according to the above implementation process, which will not be repeated here.
  • the required bandwidth of the multicast stream is the actual bandwidth value.
  • the actual bandwidth values of the multicast stream G1-multicast stream G9 are pre-configured into the PE device 11, the PE device 12, and the PE device 13.
  • the PE device 11, the PE device 12, and the PE device may not know the actual bandwidth value of each multicast stream. Therefore, the required bandwidth of the multicast stream may also be the bandwidth weight. As shown in Table 2, the bandwidth weight of each multicast stream is determined to be 1.
  • Multicast streaming First ratio Second ratio Third ratio Definite DF G1 0/1000 0/2000 0/1000 PE3 G2 0/1000 0/2000 1/1000 PE2 G7 0/1000 1/2000 1/1000 PE1 G8 1/1000 1/2000 1/1000 PE2 G3 1/1000 2/2000 1/1000 PE3 G6 1/1000 2/2000 2/1000 PE2 G5 1/1000 3/2000 2/1000 PE1 G4 2/1000 3/2000 2/1000 PE2 G9 2/1000 4/2000 2/1000 PE3 / 2/1000 4/2000 3/1000 /
  • the process for the PE device 11 to implement the DF election according to Table 2 can be referred to the foregoing description of the process for the PE device 11 to implement the DF election according to Table 1, which will not be repeated here.
  • the multicast streams transmitted by the Ethernet link 11 are the multicast stream G7 and the multicast stream G5, and the total required bandwidth of the multicast stream is 2;
  • Ethernet The multicast streams transmitted by the network link 12 are the multicast stream G2, the multicast stream G8, the multicast stream G6, and the multicast stream G4, and the total required bandwidth of the multicast stream is 4;
  • the multicast stream is multicast stream G1, multicast stream G3, and multicast stream G8.
  • the sum of the required bandwidth of the multicast stream is 3.
  • the first joining synchronization route includes a first multicast DF extended community attribute
  • the first multicast DF extended community attribute carries the IP address of the PE device that is the DF of the first multicast stream.
  • the PE device 11 and the PE device 12 in FIG. 1 can perform DF determination respectively, and the determination results of the PE device 11 and the PE device 12 are consistent;
  • the DF can be determined separately from the PE device 13, and the determination results of the PE device 11, the PE device 12, and the PE device 13 are consistent.
  • the DF determination process may be implemented by one PE device connected by the Ethernet link in the ES, and the other PE devices connected by the Ethernet link in the ES do not perform DF determination.
  • the PE device 11 determines the DF of the first multicast stream according to the foregoing implementation manner, and the PE device 11 determines that the PE device 11 is the DF of the first multicast stream.
  • the PE device 11 generates a first multicast DF extended community (multicast DF extended community) attribute, and the first multicast DF extended community attribute is used to indicate the IP address of the DF of the first multicast stream, that is,
  • the first multicast DF extended community attribute carries the IP address of the PE device 11.
  • the PE device 11 may encapsulate the first multicast DF extended community attribute in the first joining synchronization route mentioned in the foregoing embodiment. Then, the PE device 11 sends the first joining synchronization route to the PE device 12 or to the PE device 12 and the PE device 13.
  • the PE device 12 and the PE device 13 can determine not only that the CE device 11 joins the multicast group of the first multicast stream according to the first added synchronization route, but also according to the The IP address of the PE device 11 carried in the first multicast DF extended community attribute in the first joined synchronous route learns that the DF of the first multicast stream is determined to be the PE device 11.
  • the PE device 12 and the PE device 13 directly record the mapping relationship between the first multicast stream entry and the DF, and the PE device 12 and the PE device 13 no longer perform the process of determining the DF for the first multicast stream. Therefore, the process of determining the DF of the first multicast stream is only completed by the PE device 11, which further ensures the timing consistency between the multi-homing PE devices connected to the CE device 11.
  • the method further includes that the first PE device determines the third Ethernet according to the received revocation message of the first Ethernet from the third PE device automatically discovering a route cancellation per Ethernet segment The link exits the ES, wherein the revocation message instructs the third PE device to revoke the first Ethernet and automatically discover the route per Ethernet segment; the first PE device according to the first link bandwidth and The second link bandwidth, or the first PE device determines the DF as the second multicast stream according to the value of the IP address of the first PE device and the value of the IP address of the second PE device PE device, wherein, before the third Ethernet link exits the ES, the DF of the second multicast stream is the third PE device, and the second multicast stream is the EVPN group A multicast stream transmitted from a source to a multicast group member in a second multicast group, the CE device is a multicast group member in the second multicast group; the first PE device sends a message to the second The PE device sends a third joining synchronization route corresponding to the second multicast stream
  • an Ethernet link in ES01 may request to exit ES01.
  • the reasons for the exit may include: the Ethernet link fails or the Ethernet link no longer undertakes to forward multicast services.
  • the Ethernet link 13 requests to exit ES01.
  • the PE device 13 sends to the PE device 11 and the PE device 12 a first Ethernet automatic discovery route cancellation message for each Ethernet segment (Ethernet AD).
  • the revocation message instructs the PE device 13 to revoke the first Ethernet automatic discovery route per Ethernet segment.
  • the PE device 11 determines that the DF of the second multicast stream is the PE device 13 according to the mapping relationship between the multicast stream entry stored in the PE device 11 and the DF.
  • the second multicast stream is a multicast stream transmitted from the multicast source on the network side of the EVPN to members of the multicast group in the second multicast group, and the CE device 11 is the second multicast group Member of the multicast group in.
  • the PE device 11 determines whether the first link bandwidth is greater than the second link bandwidth, or the PE device 11 determines whether the value of the IP address of the PE device 11 is greater than the value of the IP address of the PE device 12.
  • the PE device 11 determines the PE device 11 as the first Two DF for multicast streaming.
  • the PE device 11 updates the correspondence between the second multicast flow entry stored in the PE device 11 and the DF.
  • the PE device 11 also sends to the PE device 12 a third joining synchronization route corresponding to the second multicast stream, the third joining synchronization route includes a second multicast DF extended community attribute, and the second multicast DF extended community
  • the attribute carries the IP address of the PE device 11.
  • the PE device 12 updates the correspondence between the second multicast flow entry stored in the PE device 12 and the DF according to the third joining synchronization route.
  • the PE device 11 determines the PE device 12 as DF of the second multicast stream.
  • the PE device 11 updates the correspondence between the second multicast flow entry stored in the PE device 11 and the DF.
  • the PE device 11 also sends to the PE device 12 a third joining synchronization route corresponding to the second multicast stream, the third joining synchronization route includes a second multicast DF extended community attribute, and the second multicast DF extended community
  • the attribute carries the IP address of the PE device 12. In this way, the PE device 12 updates the correspondence between the second multicast flow entry stored in the PE device 12 and the DF according to the third joining synchronization route.
  • the multicast stream on the Ethernet link exiting the ES can be transferred to other Ethernet links in time to ensure that the forwarding of the multicast stream is not interrupted .
  • the Ethernet used in the above implementation can automatically discover the route of each Ethernet segment. Please refer to the corresponding explanation in RFC 7432, which will not be repeated here.
  • the method further includes: when the first PE device determines that the first ratio is not less than the second ratio and the first ratio is greater than the second ratio, the first PE The device determines that the first PE device is a non-DF of the first multicast stream; in response to the first PE device determining that the first PE device is a non-DF of the first multicast stream, all The first PE device does not allocate bandwidth for the first multicast stream; the first PE device automatically discovers the route for each Ethernet segment according to the received second Ethernet from the fourth PE device, and determines the fourth An Ethernet link is added to the ES, and the CE device is connected to the fourth PE device via the fourth Ethernet link; the first PE device uses the PE device as the DF of the third multicast stream by The first PE device is changed to the fourth PE device, and the third multicast stream is a multicast stream transmitted by the multicast source of the EVPN to members of the multicast group in the third multicast group, The CE device is a member of the multicast group in the third multicast group; the first PE device sends
  • the multicast stream of the DF that has been determined in the ES can be migrated to the new Ethernet link.
  • a new Ethernet link 13 is added to ES01 to obtain the network scenario shown in FIG. 2.
  • the PE device 13 corresponds to the above-mentioned fourth PE device
  • the Ethernet link 13 corresponds to the above-mentioned fourth Ethernet link.
  • the PE device 13 generates a second Ethernet to automatically discover the route per Ethernet segment, and the PE device 13 sends the second Ethernet to the PE device 11 and the PE device 12 to automatically discover the route per Ethernet segment
  • the automatic discovery of each Ethernet segment route is used to instruct Ethernet link 13 to request to join ES01.
  • the PE device 11 After receiving the second Ethernet, the PE device 11 automatically discovers the route of each Ethernet segment, and determines that the Ethernet link 13 joins the ES01 according to the second Ethernet.
  • the PE device 11 may change the PE device that is the DF of the third multicast stream from the PE device 11 to the PE device 13.
  • the PE device 11 updates the correspondence between the third multicast stream entry stored in the PE device 11 and the DF, and updates the DF of the third multicast stream from the PE device 11 to the PE device 13. Then, the PE device 11 sends the fourth join synchronization route corresponding to the third multicast stream to the PE device 12 and the PE device 13, the fourth join synchronization route includes the third multicast DF extended community attribute, and the third The multicast DF extended community attribute carries the IP address of the PE device 13.
  • the PE device 12 receives the fourth added synchronization route, and updates the DF of the third multicast stream from the PE device 11 to the PE device 13 according to the IP address of the PE device 13 in the fourth added synchronization route.
  • the PE device 12 receives the fourth added synchronization route, and stores the correspondence between the third multicast flow entry and the DF according to the IP address of the PE device 13 in the fourth added synchronization route.
  • the multicast stream on the Ethernet link with a higher bandwidth occupancy rate in the ES can be migrated to the new Ethernet link, thereby improving each of the ES The balance of the Ethernet link.
  • FIG. 4 is a schematic structural diagram of a first PE device 1000 according to an embodiment of the present application.
  • the first PE device 1000 shown in FIG. 4 may perform the corresponding steps performed by the first PE device in the method of the foregoing embodiment.
  • the first PE device is deployed in an EVPN, the EVPN further includes a second PE device and a CE device, the CE device is connected to the first PE device via a first Ethernet link, and the CE device is The second Ethernet link is connected to the second PE device, and the first Ethernet link and the second Ethernet link belong to the same ES.
  • the first PE device 1000 includes a receiving unit 1002 and a processing unit 1004.
  • the receiving unit 1002 is configured to receive a first join message, where the first join message is used to instruct the CE device to request to join a first multicast group that receives a first multicast stream, the first The multicast stream is a multicast stream transmitted by the multicast source of the EVPN to members of the multicast group in the first multicast group;
  • the processing unit 1004 is configured to add the CE device to the first multicast group according to the first join message
  • the processing unit 1004 is also used to determine whether the first ratio is less than the second ratio, where the first ratio is the ratio of the first allocated bandwidth and the first link bandwidth, and the first allocated bandwidth indicates the first The allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the Ethernet link, and the first link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the first Ethernet link, and the first The second ratio is the ratio of the second allocated bandwidth to the second link bandwidth.
  • the second allocated bandwidth indicates the allocated bandwidth out of the total bandwidth that can be allocated to the multicast service on the second Ethernet link.
  • the second link bandwidth indicates the total bandwidth that can be allocated to the multicast service on the second Ethernet link;
  • the processing unit 1004 determines that the first ratio is less than the second ratio, the processing unit 1004 is further configured to determine that the first PE device is the DF of the first multicast stream;
  • the processing unit 1004 In response to the processing unit 1004 determining that the first PE device is the DF of the first multicast stream, the processing unit 1004 is further configured to allocate bandwidth for the first multicast stream.
  • the EVPN further includes a third PE device, and the CE device is connected to the third PE device via a third Ethernet link, and the third Ethernet link belongs to the ES.
  • the processing unit 1004 determines whether the first ratio is smaller than the second ratio, the processing unit 1004 is also used to determine that the first ratio is smaller than the third ratio, where the third ratio is the third allocated bandwidth and the third link bandwidth Ratio, the third allocated bandwidth indicates the allocated bandwidth in the total bandwidth that can be allocated to the multicast service on the third Ethernet link, and the third link bandwidth indicates on the third Ethernet link The total bandwidth that can be allocated to multicast services.
  • the processing unit 1004 determines that the first ratio is not less than the second ratio and the first ratio is greater than the second ratio, the processing unit 1004 is further used to determine the first ratio A PE device is a non-DF of the first multicast stream. In response to the processing unit 1004 determining that the first PE device is a non-DF of the first multicast stream, the processing unit 1004 is further configured not to allocate bandwidth for the first multicast stream.
  • the processing unit 1004 determines that the first ratio is not less than the second ratio, and the first ratio is equal to the second ratio, and when the processing unit 1004 determines the first ratio
  • the processing unit 1004 determines the first ratio
  • the processing unit 1004 is further configured to determine that the first PE device is the DF of the first multicast stream.
  • the processing unit 1004 determines that the first ratio is not less than the second ratio, and the first ratio is equal to the second ratio, and when the processing unit 1004 determines the first ratio When a link bandwidth is greater than the second link bandwidth, the processing unit 1004 is further configured to determine that the first PE device is the DF of the first multicast stream.
  • the processing unit 1004 determines that the first ratio is not less than the second ratio and the first ratio is equal to the second ratio, the processing unit 1004 is also used to determine according to the Hash algorithm
  • the first PE device is the DF of the first multicast stream.
  • the first PE device further includes a sending unit 1006, and before the processing unit 1004 determines whether the first ratio is less than the second ratio, the receiving unit 1002 is further configured to receive the second PE device.
  • a second Ethernet segment route, the second Ethernet segment route includes a second link bandwidth extension community attribute, and the second link bandwidth extension community attribute is used to carry the second link bandwidth.
  • the sending unit 1006 is configured to send a first Ethernet segment route to the second PE device, the first Ethernet segment route includes a first link bandwidth extension community attribute, and the first link bandwidth The extended community attribute is used to carry the first link bandwidth.
  • the first join message is a multicast group join message sent by the CE device.
  • the sending unit 1002 is configured to send a first joining synchronization route to the second PE device, where the first joining synchronization route is used to instruct the CE device to request to join the receiving the first group Broadcast the stream in the first multicast group.
  • the first joining synchronization route includes a first multicast DF extended community attribute, and the first multicast DF extended community attribute carries the IP address of the PE device that is the DF of the first multicast stream.
  • the first join message is a second join synchronization route sent by the second PE device.
  • the processing unit 1004 is further configured to determine the withdrawal of the third Ethernet link based on the received cancellation message for automatically discovering the route of each Ethernet segment from the first Ethernet from the third PE device.
  • the ES wherein the revocation message instructs the third PE device to revoke the first Ethernet automatic discovery route per Ethernet segment.
  • the processing unit 1004 is further configured to use the first link bandwidth and the second link bandwidth, or the first PE device according to the value of the IP address of the first PE device and the second PE
  • the value of the IP address of the device determines the PE device that is the DF of the second multicast stream, where, before the third Ethernet link exits the ES, the DF of the second multicast stream is the first Three PE devices, the second multicast stream is a multicast stream transmitted from the multicast source of the EVPN to members of the multicast group in the second multicast group, and the CE device is in the second multicast group Members of the multicast group.
  • the sending unit 1006 is configured to send a third joining synchronization route corresponding to the second multicast stream to the second PE device, the third joining synchronization route includes a second multicast DF extended community attribute, the The second multicast DF extended community attribute carries the IP address of the PE device that is the DF of the second multicast stream.
  • the processing unit 1004 determines that the first ratio is not less than the second ratio and the first ratio is greater than the second ratio, the processing unit 1004 is further used to determine the first ratio A PE device is a non-DF of the first multicast stream. In response to the processing unit 1004 determining that the first PE device is a non-DF of the first multicast stream, the processing unit 1004 is further configured not to allocate bandwidth for the first multicast stream. The processing unit 1004 is further configured to automatically discover the route of each Ethernet segment according to the received second Ethernet from the fourth PE device, and determine that the fourth Ethernet link joins the ES, and the CE device passes the The fourth Ethernet link is connected to the fourth PE device.
  • the processing unit 1004 is further configured to change the PE device as the DF of the third multicast stream from the first PE device to the fourth PE device, and the third multicast stream is the multicast of the EVPN A multicast stream transmitted from a source to a multicast group member in a third multicast group, and the CE device is a multicast group member in the third multicast group.
  • the sending unit 1006 is configured to send a fourth joining synchronization route corresponding to the third multicast stream to the second PE device and the fourth PE device, where the fourth joining synchronization route includes a third multicast DF extended community attribute, the third multicast DF extended community attribute carries the IP address of the fourth PE device.
  • the first PE device shown in FIG. 4 may perform the corresponding steps performed by the first PE device in the method of the foregoing embodiment.
  • the PE device determines the multiple Ethernet links included in the ES to which the Ethernet link belongs Bandwidth usage. Then, the PE device determines the PE device corresponding to the Ethernet link with the least occupied multicast stream bandwidth as the DF of the multicast stream according to the multicast stream bandwidth occupancy of the multiple Ethernet links. Therefore, it helps to improve the balance of load sharing for transmitting multicast streams in EVPN.
  • FIG. 5 is a schematic diagram of a hardware structure of a first PE device 1100 according to an embodiment of the present application.
  • the first PE device 1100 shown in FIG. 5 may perform the corresponding steps performed by the first PE device in the method of the foregoing embodiment.
  • the first PE device 1100 includes a processor 1101, a memory 1102, an interface 1103, and a bus 1104.
  • the interface 1103 may be implemented in a wireless or wired manner, and specifically may be a network card.
  • the processor 1101, the memory 1102 and the interface 1103 are connected through a bus 1104.
  • the interface 1103 may specifically include a transmitter and a receiver, which are used to send and receive information between the first PE device and the second PE device, the third PE device, the fourth PE device, and the CE device in the foregoing embodiment.
  • the interface 1103 is used to support receiving a join message sent by the CE device or the second PE device.
  • the interface 1103 is used to support receiving an Ethernet segment route sent by the second PE device.
  • the interface 1103 is used to support sending an Ethernet segment route to the second PE device or adding a synchronous route.
  • the interface 1103 is used to support the process S101 in FIG. 3.
  • the processor 1101 is configured to execute the processing performed by the first PE device in the foregoing embodiment.
  • the processor 1101 is configured to add the CE device to the first multicast group according to the join message; determine whether the first ratio is less than the second ratio; determine that the first PE device is the DF of the first multicast stream; allocating bandwidth to the first multicast stream; and / or other processes used in the techniques described herein.
  • the processor 1101 is used to support the processes S102, S103, S104, and S105 in FIG.
  • the memory 1102 includes an operating system 11021 and an application program 11022 for storing programs, codes, or instructions. When the processor or the hardware device executes these programs, codes, or instructions, the process involving the first PE device in the method embodiment may be completed.
  • the memory 1102 may include a read-only memory (English: Read-only Memory, abbreviation: ROM) and a random access memory (English: Random Access Memory, abbreviation: RAM).
  • the ROM includes a basic input / output system (English: Basic Input / Output System, abbreviation: BIOS) or an embedded system;
  • the RAM includes an application program and an operating system.
  • BIOS Basic Input / Output System
  • the BIOS is solidified in the ROM or the bootloader boot system in the embedded system is used to start the system, and the first PE device 1100 is guided to enter a normal operating state. After the first PE device 1100 enters the normal operating state, the application program and the operating system running in the RAM are completed, thereby completing the processing procedure involving the first PE device in the method embodiment.
  • FIG. 5 only shows a simplified design of the first PE device 1100.
  • the first PE device may include any number of interfaces, processors, or memories.
  • FIG. 6 is a schematic diagram of a hardware structure of another first PE device 1200 according to an embodiment of the present application.
  • the first PE device 1200 shown in FIG. 6 may perform the corresponding steps performed by the first PE device in the method of the foregoing embodiment.
  • the first PE device 1200 includes a main control board 1210, an interface board 1230, a switching network board 1220, and an interface board 1240.
  • the main control board 1210, the interface boards 1230 and 1240, and the switching network board 1220 are connected to the system backplane through a system bus to achieve intercommunication.
  • the main control board 1210 is used to complete system management, equipment maintenance, protocol processing and other functions.
  • the switching network board 1220 is used to complete data exchange between various interface boards (interface boards are also called line cards or service boards).
  • the interface boards 1230 and 1240 are used to provide various service interfaces (for example, POS interface, GE interface, ATM interface, etc.), and implement data packet forwarding.
  • the interface board 1230 may include a central processor 1231, a forwarding entry storage 1234, a physical interface card 1233, and a network processor 1232.
  • the central processor 1231 is used to control and manage the interface board and communicate with the central processor on the main control board.
  • the forwarding entry storage 1234 is used to store forwarding entry.
  • the physical interface card 1233 is used to receive and send traffic.
  • the network storage 1232 is used to control the physical interface card 1233 to send and receive traffic according to the forwarding entry.
  • the physical interface card 1233 is used to receive the join message sent by the CE device or the second PE device, or the physical interface card 1233 is used to receive the Ethernet segment route sent by the second PE device.
  • the physical interface card 1233 After the physical interface card 1233 receives the join message sent by the CE device or the second PE device, or after receiving the Ethernet segment route sent by the second PE device, the physical interface card 1233 adds the join message
  • the message or the Ethernet segment route is sent to the central processor 1211 via the central processor 1231, and the central processor 1211 processes the join message or the Ethernet segment route.
  • the central processor 1211 is further configured to add the CE device to the first multicast group according to the join message.
  • the central processor 1211 is also used to determine whether the first ratio is less than the second ratio. When the central processor 1211 determines that the first ratio is less than the second ratio, the central processor 1211 is also used to determine that the first PE device is the DF of the first multicast stream. In response to the central processor 1211 determining that the first PE device is the DF of the first multicast stream, the central processor 1211 is also used to allocate bandwidth for the first multicast stream.
  • the central processor 1231 is also used to control the network storage 1232 to obtain the forwarding entry in the forwarding entry storage 1234, and the central processor 1231 is also used to control the network storage 1232 to send ether to the second PE device via the physical interface card 1233 Network segment routing or adding synchronous routing.
  • the central processor 1231 is also used to control the network storage 1232 to forward the multicast message of the first multicast stream to the CE device via the physical interface card 1233.
  • the operation on the interface board 1240 in this embodiment of the present invention is consistent with the operation of the interface board 1230, and for the sake of brevity, no further description is required.
  • the first PE device 1200 in this embodiment may correspond to the functions and / or various steps implemented in the foregoing method embodiments, and details are not described herein again.
  • main control boards there may be one or more main control boards. When there are multiple main control boards, the main control board and the backup main control board may be included. There may be one or more interface boards. The stronger the data processing capability of the first PE device, the more interface boards are provided. There can also be one or more physical interface cards on the interface board. There may not be a switching network board, or there may be one or more blocks. When there are multiple blocks, load sharing redundancy backup can be implemented together. Under the centralized forwarding architecture, the first PE device may not need to exchange network boards, and the interface board assumes the processing function of the service data of the entire system.
  • the first PE device may have at least one switching network board, which implements data exchange between multiple interface boards through the switching network board, and provides large-capacity data exchange and processing capabilities. Therefore, the data access and processing capabilities of the first PE device in the distributed architecture are greater than those in the centralized architecture.
  • the specific architecture used depends on the specific networking deployment scenario and is not limited here.
  • the embodiments of the present application provide a computer storage medium for storing computer software instructions used by the first PE device, which includes a program designed to execute the above method embodiment.
  • the embodiment of the present application further includes an EVPN system.
  • the EVPN system includes a first PE device, and the first PE device is the first PE device in FIG. 4 or FIG. 5 or FIG. 6 described above.
  • the steps of the method or algorithm described in conjunction with the disclosure of the present application may be implemented by hardware, or by a processor executing software instructions.
  • the software instructions can be composed of corresponding software modules, which can be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage known in the art Medium.
  • An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and can write information to the storage medium.
  • the storage medium may also be an integral part of the processor.
  • the processor and the storage medium may be located in the ASIC.
  • the ASIC may be located in the user equipment.
  • the processor and the storage medium may also exist as discrete components in the user equipment.
  • Computer-readable media includes computer storage media and communication media, where communication media includes any medium that facilitates transfer of a computer program from one place to another.
  • the storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer.

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Abstract

一种确定组播流的DF的方法、设备及系统。在EVPN场景中，CE设备双归属或多归属连接到多个PE设备。第一PE设备为所述多个PE设备中的任一PE设备。所述第一PE设备在确定以太网链路连接的CE设备加入到组播流的组播组后，确定所述以太网链路所属的ES包括的多条以太网链路的带宽占用情况，然后，根据所述多条以太网链路的组播流带宽占用情况，将组播流带宽占用最少的以太网链路对应的PE设备确定为所述组播流的DF。从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。

Description

一种确定组播流的DF的方法、设备及系统
本申请要求于2018年10月19日提交中国国家知识产权局、申请号为201811222225.6、发明名称为“一种确定组播流的DF的方法、设备及系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及一种确定组播流的DF的方法、设备及系统。
背景技术
组播(multicast)是一种通过使用一个组播地址将数据在同一时间以高效的方式发往处于传输控制协议(Transmission Control Protocol，TCP)/互联网协议(Internet Protocol，IP)网络上的多个接收者的数据传输方式。组播源经由网络中的链路向组播组中的组播组成员发送组播流，该组播组中的组播组成员均可以接收到该组播流。组播传输方式实现了组播源和组播组成员之间的点对多点的数据连接。由于组播流在每条网络链路上只需传递一次，且只有在链路出现支路时，组播流才会被复制。因此，组播传输方式提高了数据传输效率和减少了骨干网络出现拥塞的可能性。
以太网虚拟专用网络(Ethernet virtual private network，EVPN)是一种二层虚拟专用网络(virtual private network，VPN)技术。EVPN通过跨互联网协议(Internet Protocol，IP)/多协议标签交换(multiprotocol label switching，MPLS)承载网将不同地域的客户站点(customer site)连接起来，相当于这些客户站点位于同一个局域网(local area network，LAN)。
在EVPN场景中，用户边缘(customer edge，CE)设备可以经由多个运营商边缘(provider edge，PE)设备接收来自远端组播源的组播流。所述CE设备通过多条以太网链路与所述多个PE设备连接，所述多条以太网链路属于同一以太网段(Ethernet segment，ES)。为了避免所述CE设备从所述多个PE设备收到重复的流量而造成的网络资源浪费，指定转发者(designated forwarder，DF)的选举机制被引入到EVPN中。在EVPN场景中，所述多个PE设备基于哈希(Hash)算法选举DF。然而，基于哈希的DF选举机制可能导致所述多条以太网链路中的部分以太网链路超负荷和所述多条以太网链路中的部分以太网链路的带宽利用率不足，从而导致负载分担性能下降。
发明内容
有鉴于此，本申请实施例提供了一种确定组播流的DF的方法、设备及系统，在EVPN中，PE设备根据属于同一ES的多条以太网链路的带宽占用情况确定组播流的DF，从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。
本申请实施例提供的技术方案如下。
第一方面，提供了一种确定组播流的DF的方法，其特征在于，所述方法应用在以太网虚拟专用网络EVPN中，所述EVPN包括第一PE设备、第二PE设备和CE设备。所述CE设备经由第一以太网链路与所述第一PE设备连接，所述CE设备经由第二以太网链路与所述第二PE设备连接，所述第一以太网链路和所述第二以太网链路属于同一个ES。所述方法包括，所述第一PE设备接收第一加入报文，所述第一加入报文用于指示所述CE设备请求加入到接收第一组播流的第一组播组中，所述第一组播流是所述EVPN的组播源向所述第一组播组中的组播组成员传输的组播流。然后，所述第一PE设备根据所述第一加入报文将所述CE设备加入到所述第一组播组。并且， 所述第一PE设备确定第一比率是否小于第二比率，其中，所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示所述第一以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示所述第一以太网链路上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示所述第二以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示所述第二以太网链路上可分配给组播业务的总带宽。当所述第一PE设备确定所述第一比率小于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF。其中，响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备为所述第一组播流分配带宽。
通过上述实施方式，在EVPN场景中，PE设备在确定以太网链路连接的CE设备加入到组播流的组播组后，所述PE设备确定所述以太网链路所属的ES包括的多条以太网链路的带宽占用情况。然后，所述PE设备根据所述多条以太网链路的组播流带宽占用情况，将组播流带宽占用最少的以太网链路对应的PE设备确定为所述组播流的DF。从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。
在第一方面的一种可能的实现方式中，所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所述第三PE设备连接，所述第三以太网链路属于所述ES。在所述第一PE设备确定第一比率是否小于第二比率之前，所述方法还包括，所述第一PE设备确定第一比率小于第三比率，其中，所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示所述第三以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第三链路带宽指示所述第三以太网链路上可分配给组播业务的总带宽。
在第一方面的又一种可能的实现方式中，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的非指定转发者(non-designated forwarder，non-DF)。响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽。
在第一方面的再一种可能的实现方式中，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一PE设备的IP地址的值大于所述第二PE设备的IP地址的值时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF。
在第一方面的再一种可能的实现方式中，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一链路带宽大于所述第二链路带宽时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF。
在第一方面的再一种可能的实现方式中，所述方法还包括：当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，所述第一PE设备根据Hash算法确定所述第一PE设备是所述第一组播流的DF。
在第一方面的再一种可能的实现方式中，在所述第一PE设备确定第一比率是否小于第二比率之前，所述方法还包括，所述第一PE设备接收所述第二PE设备发送的第二以太网段路由，所述第二以太网段路由包括第二链路带宽扩展团体属性，所述第 二链路带宽扩展团体属性用于携带所述第二链路带宽。所述第一PE设备向所述第二PE设备发送第一以太网段路由，所述第一以太网段路由包括第一链路带宽扩展团体属性，所述第一链路带宽扩展团体属性用于携带所述第一链路带宽。
通过上述实现方式，PE设备可以自动的获取ES包括的所有以太网链路的链路带宽。
在第一方面的再一种可能的实现方式中，所述第一加入报文是所述CE设备发送的组播组加入报文。
在第一方面的再一种可能的实现方式中，所述方法还包括，所述第一PE设备向所述第二PE设备发送第一加入同步路由，所述第一加入同步路由用于指示所述CE设备请求加入到接收所述第一组播流的所述第一组播组中。
在第一方面的再一种可能的实现方式中，所述第一加入同步路由包括第一组播DF扩展团体属性，所述第一组播DF扩展团体属性携带作为所述第一组播流的DF的PE设备的IP地址。
在第一方面的再一种可能的实现方式中，所述第一加入报文是所述第二PE设备发送的第二加入同步路由。
在第一方面的再一种可能的实现方式中，所述方法还包括，所述第一PE设备根据接收的、来自所述第三PE设备的第一以太网自动发现每以太网段路由的撤销消息，确定所述第三以太网链路退出所述ES，其中，所述撤销消息指示所述第三PE设备撤销所述第一以太网自动发现每以太网段路由。所述第一PE设备根据所述第一链路带宽和所述第二链路带宽，或者所述第一PE设备根据所述第一PE设备的IP地址的值和所述第二PE设备的IP地址的值，确定作为第二组播流的DF的PE设备，其中，在所述第三以太网链路退出所述ES之前，所述第二组播流的DF是所述第三PE设备，所述第二组播流是所述EVPN的组播源向第二组播组中的组播组成员传输的组播流，所述CE设备是所述第二组播组中的组播组成员。所述第一PE设备向所述第二PE设备发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带作为所述第二组播流的DF的PE设备的IP地址。
通过上述实现方式，当ES中的以太网链路退出ES时，退出ES的以太网链路上的组播流可以被及时的转移到其他以太网链路上，确保组播流的转发不中断。
在第一方面的再一种可能的实现方式中，所述方法还包括,当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF。响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽。所述第一PE设备根据接收的、来自所述第四PE设备的第二以太网自动发现每以太网段路由，确定第四以太网链路加入所述ES，所述CE设备经由所述第四以太网链路与所述第四PE设备连接。所述第一PE设备将作为第三组播流的DF的PE设备由所述第一PE设备变更为所述第四PE设备，所述第三组播流是所述EVPN的组播源向第三组播组中的组播组成员传输的组播流，所述CE设备是所述第三组播组中的组播组成员。所述第一PE设备向所述第二PE设备和所述第四PE设备发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF 扩展团体属性，所述第三组播DF扩展团体属性携带所述第四PE设备的IP地址。
通过上述实现方式，当新的以太网链路加入ES时，ES中带宽占用率较高的以太网链路上的组播流可以被迁移到新的以太网链路上，从而提高ES中各个以太网链路的均衡性。
第二方面，提供了一种第一PE设备，所述第一PE设备具有实现上述方法中第一PE设备行为的功能。所述功能可以基于硬件实现，也可以基于硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
在一个可能的设计中，第一PE设备的结构中包括处理器和接口，所述处理器被配置为支持第一PE设备执行上述方法中相应的功能。所述接口用于支持第一PE设备与第二网络设备或发话端设备或收听端设备之间的通信，向第二网络设备或发话端设备或收听端设备发送上述方法中所涉及的信息或者指令，或者从第二网络设备或发话端设备或收听端设备接收上述方法中所涉及的信息或者指令。所述第一PE设备还可以包括存储器，所述存储器用于与处理器耦合，其保存第一PE设备必要的程序指令和数据。
在另一个可能的设计中，所述第一PE设备包括：处理器、发送器、接收器、随机存取存储器、只读存储器以及总线。其中，处理器通过总线分别耦接发送器、接收器、随机存取存储器以及只读存储器。其中，当需要运行第一PE设备时，通过固化在只读存储器中的基本输入/输出系统或者嵌入式系统中的bootloader引导系统进行启动，引导第一PE设备进入正常运行状态。在第一PE设备进入正常运行状态后，在随机存取存储器中运行应用程序和操作系统，使得该处理器执行第一方面或第一方面的任意可能的实现方式中的方法。
第三方面，提供一种第一PE设备，所述第一PE设备包括：主控板和接口板，进一步，还可以包括交换网板。所述第一PE设备用于执行第一方面或第一方面的任意可能的实现方式中的方法。具体地，所述第一PE设备包括用于执行第一方面或第一方面的任意可能的实现方式中的方法的模块。
第四方面，提供一种第一PE设备，所述第一PE设备包括控制器和第一转发子设备。所述第一转发子设备包括：接口板，进一步，还可以包括交换网板。所述第一转发子设备用于执行第三方面中的接口板的功能，进一步，还可以执行第三方面中交换网板的功能。所述控制器包括接收器、处理器、发送器、随机存取存储器、只读存储器以及总线。其中，处理器通过总线分别耦接接收器、发送器、随机存取存储器以及只读存储器。其中，当需要运行控制器时，通过固化在只读存储器中的基本输入/输出系统或者嵌入式系统中的bootloader引导系统进行启动，引导控制器进入正常运行状态。在控制器进入正常运行状态后，在随机存取存储器中运行应用程序和操作系统，使得该处理器执行第三方面中主控板的功能。
第五方面，提供了一种计算机存储介质，用于储存为上述第一PE设备所用的程序、代码或指令，当处理器或硬件设备执行这些程序、代码或指令时可以完成上述第一方面中第一PE络设备的功能或步骤。
第六方面，提供一种EVPN系统，所述EVPN系统包括第一PE设备，所述第一PE设备为前述第二方面或第三方面或第四方面中的第一PE设备。
通过上述方案，在EVPN场景中，PE设备在确定以太网链路连接的CE设备加入到 组播流的组播组后，所述PE设备确定所述以太网链路所属的ES包括的多条以太网链路的带宽占用情况。然后，所述PE设备根据所述多条以太网链路的组播流带宽占用情况，将组播流带宽占用最少的以太网链路对应的PE设备确定为所述组播流的DF。从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。
附图说明
图1为本申请实施例的一种EVPN结构示意图；
图2为本申请实施例的另一种EVPN结构示意图；
图3为本申请实施例的一种确定组播流的DF的方法流程图；
图4为本申请实施例的第一PE设备的结构示意图；
图5为本申请实施例的第一PE设备的硬件结构示意图；
图6为本申请实施例的另第一PE设备的硬件结构示意图。
具体实施方式
下面通过具体实施例，分别进行详细的说明。
本申请所涉及的EVPN技术可以参见因特网工程任务组(英文：Internet Engineering Task Force，缩写：IETF)请求注解(英文：Request For Comments，缩写：RFC)7432的说明，所述RFC7432的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中。
图1为本申请实施例的一种EVPN结构示意图。如图1所示，所述EVPN包括接入侧和网络侧。所述接入侧用于接收来自所述网络侧的组播流，所述接入侧通过IP网络与网络侧通信。其中，所述IP网络可以是城域网(metropolitan area network，MAN)或数据中心(data center，DC)网络或移动承载网(mobile bearer network)或固网(fixed network)。其中，典型的移动承载网是互联网协议化无线接入网(Internet Protocol radio access network，IP RAN)。
所述接入侧包括CE设备11、PE设备11和PE设备12。CE设备11经由以太网链路11与PE设备11连接，CE设备11经由以太网链路12与PE设备12连接，以太网链路11和以太网链路12属于同一个ES，如图1中的ES01。如此这样，CE设备11经由2条以太网链路双归属到PE设备11和PE设备12。以太网段标识(Ethernet segment identifier，ESI)可以用于标识ES01。以图1为例，以太网链路11和以太网链路12的ES01的ESI值为同一个值，并且该值为非零值。ESI包括类型(Type)域和ESI值域，其中Type域用于指示ESI的生成方式。常用的两种生成方式是Type0和Type1，其中Type0表示通过手工配置生成，Type1表示通过PE设备和CE设备之间运行的链路聚合控制协议(link aggregation control protocol，LACP)生成，所述ESI值域的取值范围为0至0xFF，其中“0x”表示16进制。ES和ESI的生成及设置可以参见RFC7432中的第5章的说明。可选的，PE设备11通过框间链路与PE设备12连接。PE设备11和PE设备12可以是路由器或三层交换机。CE设备11可以是路由器或交换机或主机。本申请实施例中的PE设备11、PE设备12和CE设备11可以是RFC7432中定义的相应设备。当CE设备11是路由器或交换机时，可以连接一台或多台主机。其中，主机可以是物理设备或虚拟机(virtual machine，VM)。
在EVPN中，PE设备11和PE设备12是一对边界网关协议(border gateway protocol，BGP)对等体(BGP peer)。BGP peer也可以被称为EVPN peer。其中，“一对BGP peer” 可以被理解为：一个设备是另一个设备的BGP peer。例如，PE设备11与PE设备12是一对BGP peer可以被理解为指PE设备11是PE设备12的BGP peer，或者被理解为PE设备12是PE11设备的BGP peer。所述BGP peer也可以被称为BGP邻居；相应的，EVPN peer也可以被称为EVPN邻居。在本申请中，为了说明方便，后续实施例中统一使用BGP peer。所述BGP peer通过BGP中规定的OPEN消息建立，并通过KEEPALIVE消息维持建立的BGP peer。所述OPEN消息和KEEPALIVE消息的实现可以参见IETF RFC2858和IETF RFC1771的相关说明。另外，建立BGP peer的两端设备中可以部署路由反射器(英文：route reflector，缩写：RR)，从而利用RR完成BGP peer的建立。
所述网络侧包括PE设备21和CE设备21。PE设备21与CE设备21连接，PE设备21通过第一通信链路与PE设备11通信和PE设备21通过第二通信链路与PE设备12通信。
图2为本申请实施例的另一种EVPN结构示意图。图2所示的EVPN与图1所示的EVPN结构类似。图2所示的EVPN结构可以理解为在图1所示的EVPN结构基础上，增加PE设备13而获得的EVPN。下面针对图2与图1不同之处进行说明，图2与图1相同之处不进行赘述。
CE设备11经由以太网链路13与PE设备13连接，以太网链路13属于ES01。因此，以太网链路11、以太网链路12和以太网13属于同一个ES。如此这样，CE设备11经由3条以太网链路多归属到PE设备11、PE设备12和PE设备13。PE设备13通过框间链路与PE设备11连接，PE设备13还通过框间链路与PE设备12连接。PE设备13通过第三通信链路与PE设备21通信。根据前述，在图2中，PE设备11、PE设备12和PE设备13中的任意两个PE设备是一对BGP peer。具体的，PE设备11和PE设备12是一对BGP peer，PE设备11和PE设备13是一对BGP peer，以及PE设备12和PE设备13是一对BGP peer。
在本申请实施方式中，CE设备21作为发送组播流的组播源设备，CE设备11可以作为组播流的接收设备。例如，CE设备21发送组播流01，PE设备21负责向IP网络转发组播流01。在图1中，PE设备11和PE设备12均接收组播流01。如果CE设备11是组播流01对应的组播组中的组播组成员，PE设备11用于经由以太网链路11向CE设备11转发组播流01，PE设备12用于经由以太网链路12向CE设备11转发组播流01。在图2中，PE设备11、PE设备12和PE设备13均接收组播流01。如果CE设备11是组播流01对应的组播组中的组播组成员，PE设备11用于经由以太网链路11向CE设备11转发组播流01，PE设备12用于经由以太网链路12向CE设备11转发组播流01，以及PE设备13用于经由以太网链路13向CE设备11转发组播流01。
在图1中，如果PE设备11和PE设备12均向CE设备11转发组播流01，将导致CE设备11重复接收流量。在EVPN场景中，通过使用DF机制，可以避免CE设备11重复接收流量。如图1所示，以太网链路11和以太网链路12属于同一个ES。假设PE设备11为组播流01的DF，PE设备12为组播流01的非指定转发者(non-designated forwarder，non-DF)。这样，作为组播流01的DF的PE设备11负责向CE设备11转发组播流01，作为组播流01的non-DF的PE设备12不向CE设备 11转发组播流01。
同样道理，在图2中，以太网链路11，以太网链路12和以太网链路13属于同一个ES。对于同一条组播流，属于同一ES的以太网链路中仅有一条以太网链路连接的PE设备作为DF。如图1所示，假设PE设备11为组播流01的DF，PE设备12和PE设备13为组播流01的non-DF。这样，作为组播流01的DF的PE设备11负责向CE设备11转发组播流01，作为组播流01的non-DF的PE设备12和PE设备13不向CE设备11转发组播流01。
在确定组播流的DF的实现方式中，RFC 7432提供了一种可能的实现方式。即，根据属于同一个ES的PE设备的IP地址和虚拟局域网(virtual local area network，VLAN)标识符(identifier，ID)，选举确定对应VLAN的DF和non-DF。具体的实现方式可以参见RFC 7432的解释和说明，此处不进行赘述。
在实现确定组播流的DF的另一种可能的实现方式中，PE设备可以基于最高随机权重(Highest Random Weight，HRW)算法确定组播流的DF，其中，HRW算法属于Hash算法的一种实现方式。具体的实现方式可以参见IETF的工作组草案draft-ietf-bess-evpn-df-election-framework-03(Framework for EVPN Designated Forwarder Election Extensibility)。所述工作组草案draft-ietf-bess-evpn-df-election-framework-03的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中，此处不进行赘述。
在实现确定组播流的DF的又一种可能的实现方式中，PE设备可以基于扩展的HRW算法确定组播流的DF。具体的实现方式可以参见IETF的工作组草案draft-sajassi-bess-evpn-per-mcast-flow-df-election-01(Per multicast flow Designated Forwarder Election for EVPN)。所述工作组草案draft-sajassi-bess-evpn-per-mcast-flow-df-election-01的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中，此处不进行赘述。
然而，基于Hash算法的DF选举机制(例如，前述的HRW和扩展的HRW)可能导致所述多条以太网链路中的部分以太网链路超负荷和所述多条以太网链路中的部分以太网链路的带宽利用率不足，从而导致负载分担性能下降。以图1为例，假设组播流G1-G9，共计9条组播流的组播源是CE设备21，并且CE设备11作为各组播流的组播组成员。根据HRW算法计算，PE设备11作为组播流G1-G7，共计7条组播流的DF；PE设备12作为组播流G8-G9，共计2条组播流的DF。假设每条组播流的需求带宽是100Mbps，那么以太网链路11的传输带宽负荷是700Mbps，而太网链路12的传输带宽负荷是200Mbps。从而，以太网链路11可能因为超负荷而导致拥塞，以太网链路12可能导致以太网链路的带宽利用率不足。其中，Mbps表示Mbit/s，即兆比特每秒(megabit per second)。
通过本申请的实现方式，在EVPN中，PE设备不再依靠Hash算法的DF选举机制，PE设备根据属于同一ES的多条以太网链路的带宽占用情况确定组播流的DF，从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。
图3为本申请实施例的一种确定组播流的DF的方法流程图。图2所示的方法可以应用于图1或图2所示的EVPN中。所述EVPN包括第一PE设备、第二PE设备和CE设备，所述CE设备经由第一以太网链路与所述第一PE设备连接，所述CE设备 经由第二以太网链路与所述第二PE设备连接，所述第一以太网链路和所述第二以太网链路属于同一个ES。结合图1和图2，所述第一PE设备是图1或图2中的PE设备11，所述第二PE设备是图1或图2中的PE设备12，所述CE设备是图1或图2中的CE设备11，所述第一以太网链路是图1或图2中的以太网链路11，所述第二以太网链路是图1或图2中的以太网链路12，所述ES是ES01。本申请实施方式中，在不进行特殊说明的情况下，上述特征可以按照相应的对应特征等同。图3所示的方法包括S101至S104。
S101、所述第一PE设备接收第一加入报文，所述第一加入报文用于指示所述CE设备请求加入到接收第一组播流的第一组播组中，所述第一组播流是所述EVPN的组播源向所述第一组播组中的组播组成员传输的组播流。
S102、所述第一PE设备根据所述第一加入报文将所述CE设备加入到所述第一组播组。
如图1所示，位于EVPN网络侧的CE设备21可以通过IP网络向EVPN接入侧发送组播流。具体的，CE设备21是EVPN网络侧的组播源，例如，CE设备21是为用户提供视频业务的运营商的服务器。CE设备21向PE设备21发送第一组播流。所述第一组播流可以表示为(S1，G1)，其中，S1表示所述第一组播流的组播源IP地址，即CE设备21的IP地址；G1表示第一组播组的IP地址。PE设备21可以经由IP网络向PE设备11和PE设备12转发所述第一组播流。所述第一组播流可以经由PE设备11和以太网链路11到达CE设备11，或者所述第一组播流可以经由PE设备12和以太网链路12到达CE设备11。
CE设备11为了能够接收到所述第一组播流，CE设备11需要请求加入所述第一组播的所述第一组播组。具体的，在一种可能的实现方式中，CE设备11经由以太网链路11向PE设备11发送第一组播组加入报文。所述第一组播组加入报文是第一加入报文，所述第一加入报文用于指示CE设备11请求加入到接收第一组播流的第一组播组中。PE设备11接收到所述第一组播组加入报文后，根据所述第一组播组加入报文将CE设备11加入到所述第一组播流的所述第一组播组中。如此这样，PE设备11可以确认CE设备11成为所述第一组播组中的组播组成员，CE设备11可以经由以太网链路11接收PE设备11转发的第一组播流。PE设备11接收到所述第一组播组加入报文后，PE设备11根据所述第一组播组加入报文生成第一加入同步路由(join synch route)，所述第一加入同步路由用于指示CE设备11请求加入到接收所述第一组播流的所述第一组播组中。PE设备11向PE设备12发送所述第一加入同步路由。PE设备12接收到所述第一加入同步路由后，根据所述第一加入同步路由将CE设备11加入到所述第一组播流的所述第一组播组中。如此这样，PE设备12可以确认CE设备11成为所述第一组播组中的组播组成员，CE设备11可以经由以太网链路12接收PE设备12转发的第一组播流。
在另一种可能的实现方式中，CE设备11经由以太网链路12向PE设备12发送第二组播组加入报文。PE设备12接收到所述第二组播组加入报文后，根据所述第二组播组加入报文将CE设备11加入到所述第一组播流的所述第一组播组中。如此这样，PE设备12可以确认CE设备11成为所述第一组播组中的组播组成员，CE设备11可以经由以太网链路12接收PE设备12转发的第一组播流。PE设备12接收到所述第二 组播组加入报文后，PE设备12根据所述第二组播组加入报文生成第二加入同步路由。所述第二加入同步路由是所述第一加入报文，所述第一加入报文用于指示CE设备11请求加入到接收第一组播流的第一组播组中。PE设备12向PE设备11发送所述第二加入同步路由。PE设备11接收到所述第二加入同步路由后，根据所述第二加入同步路由将CE设备11加入到所述第一组播流的所述第一组播组中。如此这样，PE设备11可以确认CE设备11成为所述第一组播组中的组播组成员，CE设备11可以经由以太网链路11接收PE设备11转发的第一组播流。
在上述实现方式中，所述第一组播组加入报文和第二组播组加入报文可以是因特网组管理协议(Internet group management protocol，IGMP)报文。相应的，第一加入同步路由和第二加入同步路由可以是IGMP加入同步路由(IGMP join synch route)。其中，所述IGMP加入同步路由的实现方式可以参见IETF的工作组草案draft-ietf-bess-evpn-igmp-mld-proxy-02(IGMP and MLD Proxy for EVPN)。所述工作组草案draft-ietf-bess-evpn-igmp-mld-proxy-02的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中，此处不进行赘述。
在上述实现方式中，所述第一组播组加入报文和第二组播组加入报文可以是协议无关组播(protocol independent multicast，PIM)报文。相应的，第一加入同步路由和第二加入同步路由可以是PIM加入同步路由(PIM join synch route)。其中，所述PIM加入同步路由的实现方式可以参见IETF的工作组草案draft-skr-bess-evpn-pim-proxy-01(PIM Proxy in EVPN Networks)。所述工作组草案draft-skr-bess-evpn-pim-proxy-01的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中，此处不进行赘述。
上述以图1为例，说明了CE设备11加入到第一组播流的第一组播组的实现方式。EVPN中可以包括多于两个的PE设备与CE设备11连接，例如图3。在图3所示的网络场景中，CE设备11可以按照上述实现方式加入第一组播流的第一组播组中。例如，CE设备11向PE设备11发送组播组加入报文，PE设备11向PE设备12和PE设备13通告加入同步路由。从而，PE设备11、PE设备12和PE设备13均可以确认CE设备11加入到所述第一组播流的所述第一组播组中。在本申请实施方式中，以CE设备11为例说明接收组播流的网络设备。在实际场景中，EVPN可以包括多个CE设备11，每个CE设备11均可以按照上述方式实现组播组的加入和组播流的接收。在本申请实施方式中，以第一组播流为例进行说明，应当理解，EVPN可以传输多条组播流。CE设备11在加入每条组播流对应的组播组中时，均可以按照上述实现方式实现。
S103、所述第一PE设备确定第一比率是否小于第二比率，其中，所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示所述第一以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示所述第一以太网链路上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示所述第二以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示所述第二以太网链路上可分配给组播业务的总带宽。
S104、当所述第一PE设备确定所述第一比率小于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF。
S105、响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备为所述第一组播流分配带宽。
根据S101和S102，参见图1，CE设备11可以经由以太网链路11接收PE设备11转发的第一组播流，或者，CE设备11可以经由以太网链路12接收PE设备12转发的第一组播流。在实际场景中，如果CE设备11同时接收到来自PE设备11和PE设备12的所述第一组播流，将导致CE设备11的流量双收，造成网络资源浪费。因此，EVPN中的DF选举机制将避免这种流量双收。PE设备11确定PE设备11是否为所述第一组播流的DF，从而确定PE设备11是否可以经由以太网链路11向CE设备11转发属于所述第一组播流的组播报文。同样道理，PE设备12确定PE设备12是否为所述第一组播流的DF，从而确定PE设备12是否可以经由以太网链路12向CE设备11转发属于所述第一组播流的组播报文。下面以PE设备11为例说明PE设备11确定所述第一组播流的DF的实现过程。
PE设备11在执行S103之前，需要获知ES01中所有以太网链路的链路带宽。如图1所示，PE设备11需要获知属于ES01的以太网链路11和以太网链路12的链路带宽。由于PE设备11连接以太网链路11，因此，PE设备11可以确定以太网链路11的第一链路带宽。所述第一链路带宽指示以太网链路11上可分配给组播业务的总带宽，也就是说，所述第一链路带宽是PE设备11经由以太网链路11向CE设备11转发组播业务的总带宽。具体的，PE设备11可能经由以太网链路11向CE设备11转发多种类型业务，例如单播业务、组播业务和广播业务。在本申请实施方式中，所述第一链路带宽是指PE设备11经由以太网链路11向CE设备11转发组播业务的可分配带宽，即，PE设备11经由以太网链路11向CE设备11转发组播流的需求带宽总和。所述第一链路带宽的具体数值可以由PE设备11根据PE设备11的线卡的转发能力确定。例如，PE设备11的线卡的转发能力被表示为带宽2000Mbps，其中，500Mbps被分配给单播业务使用、1000Mbps被分配给组播业务使用和500Mbps被分配给广播业务使用，那么，1000Mbps是所述第一链路带宽的具体数值。所述第一链路带宽的具体数值也可以由PE设备11根据以太网链路11的物理带宽确定。例如，太网链路11的物理带宽被表示为2000Mbps，其中，500Mbps被分配给单播业务使用、1000Mbps被分配给组播业务使用和500Mbps被分配给广播业务使用，那么，1000Mbps是所述第一链路带宽的具体数值。同样道理，PE设备12可以通过上述实现方式确定以太网链路12的第二链路带宽，所述第二链路带宽指示PE设备12经由以太网链路12向CE设备11转发组播业务的可分配带宽，即，PE设备12经由以太网链路12向CE设备11转发组播流的需求带宽总和。因此，在本申请实施方式中，以太网链路的链路带宽是指用于转发组播业务的带宽。
PE设备11还需要获知以太网链路12的第二链路带宽。在一种可能的实现方式中，PE设备11可以通过静态配置的方式获知所述第二链路带宽。具体的，网络管理员在PE设备11中直接配置ES01包括的以太网链路的链路带宽。在又一种可能的实现方式中，EVPN可能包括网管设备，所述网管设备向PE设备11发送ES01包括的以太网链路的链路带宽。在再一种可能的实现方式中，PE设备11接收PE设备12发送的第二以太网段路由，所述第二以太网段路由包括第二链路带宽扩展团体(link bandwidth extended community)属性，所述第二链路带宽扩展团体属性用于携带所述第二链路带 宽。PE设备11根据所述第二以太网段路由可以获取所述第二链路带宽。其中，所述第二以太网段路由的实现方式可以参见RFC 7432中的相应解释，所述第二链路带宽扩展团体的实现方式可以参见IETF的工作组草案draft-ietf-idr-link-bandwidth-07(BGP Link Bandwidth Extended Community)。所述工作组草案draft-ietf-idr-link-bandwidth-07的内容好像整体复制一般以引用的方式并入(incorporated by reference)本申请中，此处不进行赘述。同样道理，PE设备11还可以向PE设备12发送第一以太网段路由，所述第一以太网段路由包括第一链路带宽扩展团体属性，所述第一链路带宽扩展团体属性用于携带所述第一链路带宽。PE设备12根据所述第一以太网段路由可以获取所述第一链路带宽。
通过上述实现方式，PE设备11可以获得ES01包括的所有以太网链路的链路带宽，同样的方式，PE设备12也可以获得ES01包括的所有以太网链路的链路带宽。如图1所示，PE设备11在获取所述第一链路带宽和所述第二链路带宽后，可以根据所述第一链路带宽和所述第二链路带宽确定第一比率和第二比率。
所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示以太网链路11上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示以太网链路11上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示以太网链路12上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示以太网链路12上可分配给组播业务的总带宽。其中，所述第一分配带宽是指：在以太网链路11上可以被分配给组播业务的总带宽中已经分配给组播业务的带宽。例如，所述第一链路带宽的值为1000Mbps。组播流G1和组播流G2的DF是PE设备11，并且，组播流G1对应的组播组包括CE设备11和组播流G2对应的组播组包括CE设备11。其中，组播流G1和组播流G2均不包括前述的第一组播流。PE设备11为组播流G1分配的组播业务的带宽是100Mbps，PE设备11为组播流G2分配的组播业务的带宽是200Mbps。因此，在上述1000Mbps中，已分配的带宽为300Mbps，剩余的已分配的带宽为700Mbps。
结合上述描述，所述第一比率和所述第二比率还可以按照下面描述进行理解。所述第一比率是以PE设备11作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总和与第一链路带宽的比率。所述第二比率是以PE设备12作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总和与第二链路带宽的比率。其中，以PE设备11作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总和具体是指：CE设备11已经加入的组播组对应的组播流，并且这些组播流是以PE设备11作为DF向CE设备11进行转发，PE设备11确定这些组播流的需求带宽的总和。以PE设备12作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总和具体是指：CE设备11已经加入的组播组对应的组播流，并且这些组播流是以PE设备12作为DF向CE设备11进行转发，PE设备11确定这些组播流的需求带宽的总和。其中，本申请实施方式中提及的“组播流的需求带宽总和”等同于本申请实施方式中提及的“可分配给组播业务的总带宽中已分配的带宽”，两者仅仅是表述方式不同。
举例说明，假设CE设备11已经加入到组播流G1的组播组、组播流G2的组播组、组播流G3的组播组和组播流G4的组播组，也就是说，CE设备11分别成为G1的组播组成员、G2的组播组成员、G3的组播组成员和G4的组播组成员。并且，PE 设备11是向CE设备11转发G1和G2的DF，PE设备12是向CE设备11转发G3和G4的DF。其中，传输G1的需求带宽是100Mbps，传输G2的需求带宽是50Mbps，传输G3的需求带宽是150Mbps，传输G4的需求带宽是150Mbps。所述第一链路带宽是2000Mbps，所述第二链路带宽是1000Mbps。当PE设备11确定CE设备11加入到所述第一组播流的所述第一组播组后，PE设备11确定第一比率为：(G1的需求带宽+G2的需求带宽)/第一链路带宽，即第一比率＝(100Mbps+50Mbps)/2000Mbps＝0.075；PE设备11确定第二比率为：(G3的需求带宽+G4的需求带宽)/第二链路带宽，即第二比率＝(150Mbps+150Mbps)/1000Mbps＝0.3。
PE设备11在确定第一比率和第二比率后，根据计算得到的第一比率和第二比率，确定第一比率是否小于第二比率。例如，第一比率为0.075，第二比率为0.3。PE设备11确定第一比率小于第二比率，从而，PE设备11确定PE设备11是所述第一组播流的DF。另外，PE设备11还确定PE设备12是所述第一组播流的non-DF。PE设备11存储所述第一组播流的表项信息，并且，PE设备11将所述第一组播流的表项信息对应的DF标记为PE设备11，将所述第一组播流的表项信息对应的non-DF标记为PE设备12。PE设备11确定PE设备11是所述第一组播流的DF后，PE设备11为所述第一组播流分配组播业务的带宽。相应的，PE设备11更新所述第一分配带宽的值。如此这样，PE设备11在后续接收到组播流是可以根据最新的带宽占用情况确定第一比率的值和第二比率的值。PE设备11也可以根据所述第一组播流的表项信息对应的DF标记为PE设备11，经由以太网链路11向CE设备11转发属于所述第一组播流的组播报文。
通过上述实施方式，在EVPN场景中，PE设备在确定以太网链路连接的CE设备加入到组播流的组播组后，所述PE设备确定所述以太网链路所属的ES包括的多条以太网链路的带宽占用情况。然后，所述PE设备根据所述多条以太网链路的组播流带宽占用情况，将组播流带宽占用最少的以太网链路对应的PE设备确定为所述组播流的DF。从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。应当理解，本申请的实施方式是以PE设备11作为示例说明ES中以太网链路连接的PE设备确定DF的实现方式。在实际场景中，ES中以太网链路连接的PE设备均可以按照PE设备11的实现方式实现DF的确定过程。
可选的，所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所述第三PE设备连接，所述第三以太网链路属于所述ES，在所述第一PE设备确定第一比率是否小于第二比率之前，所述方法还包括：所述第一PE设备确定第一比率小于第三比率，其中，所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示所述第三以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第三链路带宽指示所述第三以太网链路上可分配给组播业务的总带宽。
结合前述，图3示出了EVPN中的ES包括两条以太网链路的实施方式，应当理解，图3的实现方式可以应用在所述ES包括多于两条的以太网链路的场景中，也就是说，图3的实现方式可以应用在图2所示的场景中。所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所述第三PE设备连接，所述第三以太网链路属于所述ES。其中，所述第三PE设备是图2中的PE设备13，所述第三以太网链路是图2中的以太网链路13。本申请实施方式中，在不进行特殊说明的情况下，上述特 征可以按照相应的对应特征等同。
根据前述实施方式，CE设备11经由以太网链路11向PE设备11发送第一组播组加入报文。PE设备11接收到所述第一组播组加入报文后，根据所述第一组播组加入报文将CE设备11加入到所述第一组播流的所述第一组播组中。PE设备11接收到所述第一组播组加入报文后，PE设备11还向PE设备13发送所述第一加入同步路由。PE设备13接收到所述第一加入同步路由后，根据所述第一加入同步路由将CE设备11加入到所述第一组播流的所述第一组播组中。如此这样，PE设备13可以确认CE设备11成为所述第一组播组中的组播组成员，CE设备11可以经由以太网链路13接收PE设备13转发的第一组播流。在另一种可能的实现方式中，CE设备11也可以经由以太网链路13向PE设备13发送组播组加入报文，再由PE设备13根据所述组播组加入报文生成相应的加入同步路由，并向PE设备11和PE设备12发送所述加入同步路由。从而，PE设备11、PE设备12和PE设备13均可以确认CE设备11加入到所述第一组播流的所述第一组播组中。
PE设备11在确定所述第三比率之前，PE设备11可以根据前述实施方式获取以太网链路13的第三链路带宽。所述第三链路带宽指示以太网链路13上可分配给组播业务的总带宽，也就是说，所述第三链路带宽指示PE设备13经由以太网链路13向CE设备11转发组播业务的总带宽。然后，PE设备11在确定所述第三比率。所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示以太网链路13上可分配给组播业务的总带宽中已分配的带宽。也就是说，所述第三比率是以PE设备13作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总和与所述第三链路带宽的比率。PE设备13获取所述第三链路带宽和确定所述第三比率的实现方式，参见本申请前述实施方式，此处不进行赘述。
根据前述实施方式，PE设备11在确定ES01包括的所有以太网链路对应的比率(例如，前述中的第一比率、第二比率和第三比率)后，PE设备11确定所有以太网链路对应的比率中的最小比率，从而，PE设备11能够根据确定的最小比率确定出负责转发所述第一组播流的DF。在具体实现中，PE设备11可以在所有以太网链路对应的比率中任意取出两个比率进行比较，获取较小的比率。PE设备11再从所有以太网链路对应的比率中取出没有参与比较的比率，将该比率与较小的比率进行比较，直到获得ES01包括的所有以太网链路对应的比率中的最小比率。如图3所示，PE设备11首先确定所述第一比率是否小于所述第三比率。当PE设备11确定所述第一比率小于所述第三比率时，PE设备11再确定所述第一比率是否小于所述第二比率。如果PE设备11确定所述第一比率小于所述第二比率，PE设备11可以确定所述第一比率为ES01包括的所有以太网链路对应的比率中的最小比率。从而，PE设备11作为向CE设备11转发所述第一组播流的DF。其中，PE设备11确定所述第一比率小于所述第三比率的实现方式可以参见本申请前述实施方式的说明，此处不进行赘述。
应当理解，图3中的PE设备12和PE设备13均可以按照PE设备11的实现方式确定所述第一组播流的DF。例如，结合前述实现方式，PE设备11将PE设备11确定为所述第一组播流的DF，将PE设备12和PE设备13确定为所述第一组播流的non-DF。相应的，PE设备12将PE设备11确定为所述第一组播流的DF，将PE设备12和PE设备13确定为所述第一组播流的non-DF；PE设备13将PE设备11确定为所述第一 组播流的DF，将PE设备12和PE设备13确定为所述第一组播流的non-DF。如此这样，PE设备11、PE设备12和PE设备13确定出的DF结果一致，从而保证PE设备11负责转发所述第一组播流，避免CE设备11的流量双收或流量多收。
可选的，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF。响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽。
结合前述，在图1所示的场景中，如果所述第一比率大于所述第二比率，PE设备11将PE设备11确定为所述第一组播流的non-DF和将PE设备12确定为所述第一组播流的DF。相应的，PE设备12也会按照前述的实现方式将PE设备11确定为所述第一组播流的non-DF和将PE设备12确定为所述第一组播流的DF。从而，所述PE设备11不为所述第一组播流分配带宽，也就是说，PE设备11用于不向所述CE设备转发属于所述第一组播流的组播报文，PE设备12用于向所述CE设备转发属于所述第一组播流的组播报文。相应的，由于PE设备11将PE设备12确定为所述第一组播流的DF，PE设备11更新PE设备11存储的所述第二分配带宽的值，从而使得所述第二分配带宽的值包括所述第一组播流的需求带宽。在图2所示的场景中，如果所述第一比率大于所述第二比率，并且所述第一比率小于所述第三比率，PE设备11将PE设备11和PE设备13确定为所述第一组播流的non-DF和将PE设备12确定为所述第一组播流的DF。相应的，PE设备12和PE设备13确定的结果与PE设备11确定的结果一致。
其中，PE设备11用于不向所述CE设备转发属于所述第一组播流的组播报文。在一种可能的实现方式中，PE设备11在确定自身为所述第一组播流的non-DF后，向PE设备21发送通告消息，所述通告消息指示PE设备11是所述第一组播流的non-DF。PE设备21根据所述通告消息不再向PE设备11转发所述第一组播流的组播报文。在另一种可能的实现方式中，PE设备11在确定自身为所述第一组播流的non-DF后，继续接收PE设备21转发的所述第一组播流的组播报文。PE设备11收到所述第一组播流的组播报文后，直接丢弃所述第一组播流的组播报文，或者等待所述第一组播流的组播报文老化后在进行丢弃。
可选的，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一PE设备的IP地址的值大于所述第二PE设备的IP地址的值时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备用于经由所述第一以太网链路向所述CE设备转发属于所述第一组播流的组播报文。
结合前述，如果所述第一比率等于所述第二比率，PE设备11进一步确定PE设备11的IP地址的值是否大于PE设备12的IP地址的值。其中，PE设备11的IP地址和PE设备12的IP地址是建立BGP peer时使用的IP地址，具体的，可以是PE设备11的设备IP地址和PE设备12的设备IP地址。当PE设备11的IP地址的值大于PE设备12的IP地址的值时，PE设备11确定PE设备11是所述第一组播流的DF，所述PE设备11负责向CE设备11转发属于所述第一组播流的组播报文。
可选的，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第 二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一链路带宽大于所述第二链路带宽时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备用于经由所述第一以太网链路向所述CE设备转发属于所述第一组播流的组播报文。
结合前述，如果所述第一比率等于所述第二比率，PE设备11进一步确定所述第一链路带宽是否大于所述第二链路带宽。当所述第一链路带宽大于所述第二链路带宽时，PE设备11确定PE设备11是所述第一组播流的DF，所述PE设备11负责向CE设备11转发属于所述第一组播流的组播报文。
可选的，所述方法还包括，当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，所述第一PE设备根据Hash算法确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备用于经由所述第一以太网链路向所述CE设备转发属于所述第一组播流的组播报文。
结合前述，如果所述第一比率等于所述第二比率，PE设备11进一步根据Hash算法确定所述第一组播流的DF。
下面以图2为例，说明本申请实施方式的实现过程。
假设图2所示的EVPN场景包括组播流G1-组播流G9，共计9条组播流。其中，组播流G1-组播流G5的需求带宽均为90Mbps，组播流G6-组播流G9的需求带宽均为150Mbps。组播流G1-组播流G9均可以由图2所示的EVPN的网络侧传输到EVPN的接入侧。第一链路带宽为1000Mbps，第二链路带宽为2000Mbps，第三链路带宽为1000Mbps。PE设备13的IP地址最大。PE设备11、PE设备12和PE设备13均可以按照表1依次确定各个组播流的DF。本实施方式在进行说明时，以PE设备11执行表1所示的DF选举过程为例进行说明。并且，根据前述实施方式，PE设备11、PE设备12和PE设备之间已经相互同步了第一链路带宽、第二链路带宽和第3链路带宽。
组播流 第一比率 第二比率 第三比率 确定的DF
G1 0/1000 0/2000 0/1000 PE3
G2 0/1000 0/2000 90/1000 PE2
G7 0/1000 90/2000 90/1000 PE1
G8 150/1000 90/2000 90/1000 PE2
G3 150/1000 240/2000 90/1000 PE3
G6 150/1000 240/2000 180/1000 PE2
G5 150/1000 390/2000 180/1000 PE1
G4 240/1000 390/2000 180/1000 PE3
G9 240/1000 390/2000 270/1000 PE2
/ 240/1000 540/2000 270/1000 /
表1
参见表1，其中，第一列表示CE设备11依次加入的组播组对应的组播流；第二列、第三列和第四列分别表示依据前述实施方式的实现方法确定的第一比率、第二比率和第三比率；第五列表示PE设备11确定出的对应组播流的DF。
参见表1的第1条表项，组播流G1是CE设备11请求接收的第一个组播流，因此，以PE设备11作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总为0，以PE设备12作为DF并且以CE设备11作为组播组成员的组播流的需求带宽 总为0，以PE设备13作为DF并且以CE设备11作为组播组成员的组播流的需求带宽总为0。当CE设备11加入组播流G1的组播组时，PE设备11确定第一比率、第二比率和第三比率相等，均为0。进一步，PE设备11确定PE设备13的IP地址的值最大。从而，PE设备11确定PE设备13为组播流G1的DF。
参见表1的第2条表项，PE设备11在为组播流G1确定了DF之后，CE设备11加入组播流G2的组播组。PE设备11根据CE设备11加入组播流G2的组播组，重新确定第一比率、第二比率和第三比率。PE设备11确定第一比率和第二比率均小于第三比率，并且，第一比率等于第二比率。进一步，PE设备11确定第二链路带宽大于第一链路带宽。从而，PE设备11确定PE设备12为组播流G2的DF。
参见表1的第2条表项，PE设备11在为组播流G2确定了DF之后，CE设备11加入组播流G7的组播组。PE设备11根据CE设备11加入组播流G7的组播组，重新确定第一比率、第二比率和第三比率。PE设备11确定第一比率为最小比率。从而，PE设备11确定PE设备11为组播流G7的DF。
表1中的组播流G8、组播流G3、组播流G6、组播流G5、组播流G4和组播流G9可以根据本实施方式的上述规则依次进行DF选举。此处不再进行赘述。表1的最后一条表项表示：PE设备11在完成组播流G9的DF选举后，将组播流G9的表项存储到PE设备11中，以便后续再有CE设备11加入组播流的组播组时，重新确定第一比率、第二比率和第三比率。PE设备11在按照表1所示的实现方式完成DF选举之后，以太网链路11负责传输的组播流为组播流G7和组播流G5，组播流的需求带宽总和为240Mbps；以太网链路12负责传输的组播流为组播流G2、组播流G8、组播流G6和组播流G9，组播流的需求带宽总和为540Mbps；以太网链路13负责传输的组播流为组播流G1、组播流G3和组播流G4，组播流的需求带宽总和为270Mbps。另外，PE设备12和PE设备13也可以按照上述实现过程实现DF选举，此处不进行赘述。
表1示出的实现方式中，组播流的需求带宽是实际带宽值。组播流G1-组播流G9的实际带宽值被预先配置到PE设备11、PE设备12和PE设备13中。在另一种可能的实现方式中，PE设备11、PE设备12和PE设备可能无法获知各个组播流的实际带宽值。因此，组播流的需求带宽还可以是带宽权值，如表2所示，各个组播流的带宽权值均被确定为1。
组播流 第一比率 第二比率 第三比率 确定的DF
G1 0/1000 0/2000 0/1000 PE3
G2 0/1000 0/2000 1/1000 PE2
G7 0/1000 1/2000 1/1000 PE1
G8 1/1000 1/2000 1/1000 PE2
G3 1/1000 2/2000 1/1000 PE3
G6 1/1000 2/2000 2/1000 PE2
G5 1/1000 3/2000 2/1000 PE1
G4 2/1000 3/2000 2/1000 PE2
G9 2/1000 4/2000 2/1000 PE3
/ 2/1000 4/2000 3/1000 /
表2
PE设备11按照表2实现DF选举的过程可以参见前述PE设备11按照表1实现 DF选举的过程的说明，此处不进行赘述。PE设备11在按照表2所示的实现方式完成DF选举之后，以太网链路11负责传输的组播流为组播流G7和组播流G5，组播流的需求带宽总和为2；以太网链路12负责传输的组播流为组播流G2、组播流G8、组播流G6和组播流G4，组播流的需求带宽总和为4；以太网链路13负责传输的组播流为组播流G1、组播流G3和组播流G8，组播流的需求带宽总和为3。
可选的，所述第一加入同步路由包括第一组播DF扩展团体属性，所述第一组播DF扩展团体属性携带作为所述第一组播流的DF的PE设备的IP地址。
根据前述实施方式的说明，图1中的PE设备11和PE设备12可以分别进行DF的确定，PE设备11和PE设备12确定的结果是一致的；图2中的PE设备11、PE设备12和PE设备13可以分别进行DF的确定，PE设备11、PE设备12和PE设备13确定的结果是一致的。在另一种可能的实现方式中，DF的确定过程可以由ES中的以太网链路连接的一个PE设备实现，ES中的以太网链路连接的其他PE设备不进行DF的确定。例如，PE设备11按照前述的实现方式确定第一组播流的DF，并且，PE设备11确定PE设备11为所述第一组播流的DF。PE设备11生成第一组播DF扩展团体(multicast DF extended community)属性，所述第一组播DF扩展团体属性用于指示所述第一组播流的DF的IP地址，也就是说，所述第一组播DF扩展团体属性携带PE设备11的IP地址。PE设备11可以将所述第一组播DF扩展团体属性封装在前述实施方式提及的所述第一加入同步路由中。然后，PE设备11向PE设备12或者向PE设备12和PE设备13发送所述第一加入同步路由。PE设备12和PE设备13接收到所述第一加入同步路由后，不仅可以根据所述第一加入同步路由确定CE设备11加入所述第一组播流的组播组，还可以根据所述第一加入同步路由中的所述第一组播DF扩展团体属性携带的PE设备11的IP地址获知所述第一组播流的DF被确定为PE设备11。PE设备12和PE设备13直接记录所述第一组播流表项和DF的映射关系，并且，PE设备12和PE设备13不再进行针对所述第一组播流的DF的确定过程。从而，所述第一组播流的DF的确定过程只由PE设备11完成，进一步确保了CE设备11连接的多归PE设备之间的时序一致性。
可选的，所述方法还包括，所述第一PE设备根据接收的、来自所述第三PE设备的第一以太网自动发现每以太网段路由的撤销消息，确定所述第三以太网链路退出所述ES，其中，所述撤销消息指示所述第三PE设备撤销所述第一以太网自动发现每以太网段路由；所述第一PE设备根据所述第一链路带宽和所述第二链路带宽，或者所述第一PE设备根据所述第一PE设备的IP地址的值和所述第二PE设备的IP地址的值，确定作为第二组播流的DF的PE设备，其中，在所述第三以太网链路退出所述ES之前，所述第二组播流的DF是所述第三PE设备，所述第二组播流是所述EVPN的组播源向第二组播组中的组播组成员传输的组播流，所述CE设备是所述第二组播组中的组播组成员；所述第一PE设备向所述第二PE设备发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带作为所述第二组播流的DF的PE设备的IP地址。
如图2所示，ES01中的某条以太网链路可能请求退出ES01，退出的原因可以包括：该条以太网链路发生故障或者该条以太网链路不再承担转发组播业务。举例说明，以太网链路13请求退出ES01，相应的，PE设备13向PE设备11和PE设备12发送 第一以太网自动发现每以太网段(Ethernet A-D per ES)路由的撤销消息，所述撤销消息指示PE设备13撤销所述第一以太网自动发现每以太网段路由。PE设备11接收到所述撤销消息后，根据PE设备11存储的组播流表项与DF映射关系，确定第二组播流的DF是PE设备13。其中，所述第二组播流是从所述EVPN的网络侧的组播源向第二组播组中的组播组成员传输的组播流，CE设备11是所述第二组播组中的组播组成员。PE设备11确定所述第一链路带宽是否大于所述第二链路带宽，或者PE设备11确定PE设备11的IP地址的值是否大于PE设备12的IP地址的值。当所述第一链路带宽大于所述第二链路带宽时，或者当PE设备11的IP地址的值大于PE设备12的IP地址的值时，PE设备11确定PE设备11作为所述第二组播流的DF。PE设备11更新PE设备11存储的所述第二组播流表项与DF的对应关系。PE设备11还向PE设备12发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带PE设备11的IP地址。如此这样，PE设备12根据所述第三加入同步路由更新PE设备12存储的所述第二组播流表项与DF的对应关系。相应的，当所述第一链路带宽小于所述第二链路带宽时，或者当PE设备11的IP地址的值小于PE设备12的IP地址的值时，PE设备11确定PE设备12作为所述第二组播流的DF。PE设备11更新PE设备11存储的所述第二组播流表项与DF的对应关系。PE设备11还向PE设备12发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带PE设备12的IP地址。如此这样，PE设备12根据所述第三加入同步路由更新PE设备12存储的所述第二组播流表项与DF的对应关系。
通过上述实现方式，当ES中的以太网链路退出ES时，退出ES的以太网链路上的组播流可以被及时的转移到其他以太网链路上，确保组播流的转发不中断。上述实现中使用的以太网自动发现每以太网段路由可以参见RFC 7432中的相应解释，此处不进行赘述。
可选的，所述方法还包括：当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF；响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽；所述第一PE设备根据接收的、来自所述第四PE设备的第二以太网自动发现每以太网段路由，确定第四以太网链路加入所述ES，所述CE设备经由所述第四以太网链路与所述第四PE设备连接；所述第一PE设备将作为第三组播流的DF的PE设备由所述第一PE设备变更为所述第四PE设备，所述第三组播流是所述EVPN的组播源向第三组播组中的组播组成员传输的组播流，所述CE设备是所述第三组播组中的组播组成员；所述第一PE设备向所述第二PE设备和所述第四PE设备发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF扩展团体属性，所述第三组播DF扩展团体属性携带所述第四PE设备的IP地址。
结合前述，当有新的以太网链路加入到ES中时，可以将ES中已经确定DF的组播流迁移到新的以太网链路上。举例说明，在图1所示的网络场景基础上，新的以太网链路13加入ES01，得到图2所示的网络场景。其中，PE设备13对应上述第四PE设备，以太网链路13对应上述第四以太网链路。
PE设备13生成第二以太网自动发现每以太网段路由，并且，PE设备13向PE设备11和PE设备12发送所述第二以太网自动发现每以太网段路由，所述第二以太网自动发现每以太网段路由用于指示以太网链路13请求加入ES01。PE设备11接收到所述第二以太网自动发现每以太网段路由，根据所述第二以太网自动发现每以太网段路由，确定以太网链路13加入ES01。根据前述实施方式，PE设备11确定所述第一比率大于所述第二比率时，PE设备11可以将作为第三组播流的DF的PE设备由PE设备11变更为PE设备13。具体的，PE设备11更新PE设备11存储的所述第三组播流表项与DF的对应关系，将所述第三组播流的DF由PE设备11更新为PE设备13。然后，PE设备11向PE设备12和PE设备13发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF扩展团体属性，所述第三组播DF扩展团体属性携带PE设备13的IP地址。PE设备12接收到所述第四加入同步路由，根据所述第四加入同步路由中的PE设备13的IP地址将所述第三组播流的DF由PE设备11更新为PE设备13。PE设备12接收到所述第四加入同步路由，根据所述第四加入同步路由中的PE设备13的IP地址存储所述第三组播流表项与DF的对应关系。
通过上述实现方式，当新的以太网链路加入ES时，ES中带宽占用率较高的以太网链路上的组播流可以被迁移到新的以太网链路上，从而提高ES中各个以太网链路的均衡性。
图4为本申请实施例的第一PE设备1000的结构示意图。图4所示的第一PE设备1000可以执行上述实施例的方法中第一PE设备执行的相应步骤。所述第一PE设备被部署在EVPN中，所述EVPN还包括第二PE设备和CE设备，所述CE设备经由第一以太网链路与所述第一PE设备连接，所述CE设备经由第二以太网链路与所述第二PE设备连接，所述第一以太网链路和所述第二以太网链路属于同一个ES。如图4所示，所述第一PE设备1000包括接收单元1002和处理单元1004。
所述接收单元1002，用于接收第一加入报文，所述第一加入报文用于指示所述CE设备请求加入到接收第一组播流的第一组播组中，所述第一组播流是所述EVPN的组播源向所述第一组播组中的组播组成员传输的组播流；
所述处理单元1004，用于根据所述第一加入报文将所述CE设备加入到所述第一组播组；
所述处理单元1004还用于确定第一比率是否小于第二比率，其中，所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示所述第一以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示所述第一以太网链路上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示所述第二以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示所述第二以太网链路上可分配给组播业务的总带宽；
当所述处理单元1004确定所述第一比率小于所述第二比率时，所述处理单元1004还用于确定所述第一PE设备是所述第一组播流的DF；
响应于所述处理单元1004确定所述第一PE设备是所述第一组播流的DF，所述处理单元1004还用于为所述第一组播流分配带宽。
可选的，所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所 述第三PE设备连接，所述第三以太网链路属于所述ES，在所述处理单元1004确定第一比率是否小于第二比率之前，所述处理单元1004还用于确定第一比率小于第三比率，其中，所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示所述第三以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第三链路带宽指示所述第三以太网链路上可分配给组播业务的总带宽。
可选的，当所述处理单元1004确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述处理单元1004还用于确定所述第一PE设备是所述第一组播流的non-DF。响应于所述处理单元1004确定所述第一PE设备是所述第一组播流的non-DF，所述处理单元1004还用于不为所述第一组播流分配带宽。
可选的，当所述处理单元1004确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述处理单元1004确定所述第一PE设备的IP地址的值大于所述第二PE设备的IP地址的值时，所述处理单元1004还用于确定所述第一PE设备是所述第一组播流的DF。
可选的，当所述处理单元1004确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述处理单元1004确定所述第一链路带宽大于所述第二链路带宽时，所述处理单元1004还用于确定所述第一PE设备是所述第一组播流的DF。
可选的，当所述处理单元1004确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，所述处理单元1004还用于根据Hash算法确定所述第一PE设备是所述第一组播流的DF。
可选的，所述第一PE设备还包括发送单元1006，在所述处理单元1004确定第一比率是否小于第二比率之前，所述接收单元1002还用于接收所述第二PE设备发送的第二以太网段路由，所述第二以太网段路由包括第二链路带宽扩展团体属性，所述第二链路带宽扩展团体属性用于携带所述第二链路带宽。以及，所述发送单元1006，用于向所述第二PE设备发送第一以太网段路由，所述第一以太网段路由包括第一链路带宽扩展团体属性，所述第一链路带宽扩展团体属性用于携带所述第一链路带宽。
可选的，所述第一加入报文是所述CE设备发送的组播组加入报文。进一步可选的，所述发送单元1002，用于向所述第二PE设备发送第一加入同步路由，所述第一加入同步路由用于指示所述CE设备请求加入到接收所述第一组播流的所述第一组播组中。进一步可选的，所述第一加入同步路由包括第一组播DF扩展团体属性，所述第一组播DF扩展团体属性携带作为所述第一组播流的DF的PE设备的IP地址。
可选的，所述第一加入报文是所述第二PE设备发送的第二加入同步路由。
可选的，所述处理单元1004还用于根据接收的、来自所述第三PE设备的第一以太网自动发现每以太网段路由的撤销消息，确定所述第三以太网链路退出所述ES，其中，所述撤销消息指示所述第三PE设备撤销所述第一以太网自动发现每以太网段路由。所述处理单元1004还用于根据所述第一链路带宽和所述第二链路带宽，或者所述第一PE设备根据所述第一PE设备的IP地址的值和所述第二PE设备的IP地址的值，确定作为第二组播流的DF的PE设备，其中，在所述第三以太网链路退出所述ES之前，所述第二组播流的DF是所述第三PE设备，所述第二组播流是所述EVPN的组播源向第二组播组中的组播组成员传输的组播流，所述CE设备是所述第二组播组中的 组播组成员。所述发送单元1006，用于向所述第二PE设备发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带作为所述第二组播流的DF的PE设备的IP地址。
可选的，当所述处理单元1004确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述处理单元1004还用于确定所述第一PE设备是所述第一组播流的non-DF。响应于所述处理单元1004确定所述第一PE设备是所述第一组播流的non-DF，所述处理单元1004还用于不为所述第一组播流分配带宽。所述处理单元1004还用于根据接收的、来自所述第四PE设备的第二以太网自动发现每以太网段路由，确定第四以太网链路加入所述ES，所述CE设备经由所述第四以太网链路与所述第四PE设备连接。所述处理单元1004还用于将作为第三组播流的DF的PE设备由所述第一PE设备变更为所述第四PE设备，所述第三组播流是所述EVPN的组播源向第三组播组中的组播组成员传输的组播流，所述CE设备是所述第三组播组中的组播组成员。所述发送单元1006，用于向所述第二PE设备和所述第四PE设备发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF扩展团体属性，所述第三组播DF扩展团体属性携带所述第四PE设备的IP地址。
图4所示的第一PE设备可以执行上述实施例的方法中第一PE设备执行的相应步骤。在EVPN场景中，PE设备在确定以太网链路连接的CE设备加入到组播流的组播组后，所述PE设备确定所述以太网链路所属的ES包括的多条以太网链路的带宽占用情况。然后，所述PE设备根据所述多条以太网链路的组播流带宽占用情况，将组播流带宽占用最少的以太网链路对应的PE设备确定为所述组播流的DF。从而，有助于提高在EVPN中传输组播流的负载分担的均衡性。
图5为本申请实施例的第一PE设备1100的硬件结构示意图。图5所示的第一PE设备1100可以执行上述实施例的方法中第一PE设备执行的相应步骤。
如图5所示，所述第一PE设备1100包括处理器1101、存储器1102、接口1103和总线1104。其中接口1103可以通过无线或有线的方式实现，具体来讲可以是网卡。上述处理器1101、存储器1102和接口1103通过总线1104连接。
所述接口1103具体可以包括发送器和接收器，用于第一PE设备与上述实施例中的第二PE设备、第三PE设备、第四PE设备以及CE设备之间收发信息。例如，所述接口1103用于支持接收所述CE设备或者所述第二PE设备发送的加入报文。又例如，所述接口1103用于支持接收所述第二PE设备发送的以太网段路由。再例如，所述接口1103用于支持向所述第二PE设备发送以太网段路由或加入同步路由。作为举例，所述接口1103用于支持图3中的过程S101。所述处理器1101用于执行上述实施例中由第一PE设备进行的处理。例如，所述处理器1101用于根据所述加入报文将所述CE设备加入到所述第一组播组；确定第一比率是否小于第二比率；确定所述第一PE设备是所述第一组播流的DF；为所述第一组播流分配带宽；和/或用于本文所描述的技术的其他过程。作为举例，所述处理器1101用于支持图3中的过程S102、S103、S104和S105。存储器1102包括操作系统11021和应用程序11022，用于存储程序、代码或指令，当处理器或硬件设备执行这些程序、代码或指令时可以完成方法实施例中涉及第一PE设备的处理过程。可选的，所述存储器1102可以包括只读存储器(英文：Read-only Memory，缩写：ROM)和随机存取存储器(英文：Random Access Memory， 缩写：RAM)。其中，所述ROM包括基本输入/输出系统(英文：Basic Input/Output System，缩写：BIOS)或嵌入式系统；所述RAM包括应用程序和操作系统。当需要运行第一PE设备1100时，通过固化在ROM中的BIOS或者嵌入式系统中的bootloader引导系统进行启动，引导第一PE设备1100进入正常运行状态。在第一PE设备1100进入正常运行状态后，运行在RAM中的应用程序和操作系统，从而，完成方法实施例中涉及第一PE设备的处理过程。
可以理解的是，图5仅仅示出了第一PE设备1100的简化设计。在实际应用中，第一PE设备可以包含任意数量的接口，处理器或者存储器。
图6为本申请实施例的另一种第一PE设备1200的硬件结构示意图。图6所示的第一PE设备1200可以执行上述实施例的方法中第一PE设备执行的相应步骤。
如图6所述，第一PE设备1200包括：主控板1210、接口板1230、交换网板1220和接口板1240。主控板1210、接口板1230和1240，以及交换网板1220之间通过系统总线与系统背板相连实现互通。其中，主控板1210用于完成系统管理、设备维护、协议处理等功能。交换网板1220用于完成各接口板(接口板也称为线卡或业务板)之间的数据交换。接口板1230和1240用于提供各种业务接口(例如，POS接口、GE接口、ATM接口等)，并实现数据包的转发。
接口板1230可以包括中央处理器1231、转发表项存储器1234、物理接口卡1233和网络处理器1232。其中，中央处理器1231用于对接口板进行控制管理并与主控板上的中央处理器进行通信。转发表项存储器1234用于保存转发表项。物理接口卡1233用于完成流量的接收和发送。网络存储器1232用于根据所述转发表项控制物理接口卡1233收发流量。
具体的，物理接口卡1233用于接收所述CE设备或者所述第二PE设备发送的加入报文，或者物理接口卡1233用于接收所述第二PE设备发送的以太网段路由。
物理接口卡1233接收到所述CE设备或者所述第二PE设备发送的加入报文后，或者，物理接口卡1233接收到所述第二PE设备发送的以太网段路由后，将所述加入报文或所述以太网段路由经由中央处理器1231发送到中央处理器1211，中央处理器1211处理所述加入报文或所述以太网段路由。
中央处理器1211还用于根据所述加入报文将所述CE设备加入到所述第一组播组。中央处理器1211还用于确定第一比率是否小于第二比率。当中央处理器1211确定所述第一比率小于所述第二比率时，中央处理器1211还用于确定所述第一PE设备是所述第一组播流的DF。响应于所述中央处理器1211确定所述第一PE设备是所述第一组播流的DF，所述中央处理器1211还用于为所述第一组播流分配带宽。
中央处理器1231还用于控制网络存储器1232获取转发表项存储器1234中的转发表项，并且，中央处理器1231还用于控制网络存储器1232经由物理接口卡1233向所述第二PE设备发送以太网段路由或加入同步路由。中央处理器1231还用于控制网络存储器1232经由物理接口卡1233向所述CE设备转发所述第一组播流的组播报文。
应理解，本发明实施例中接口板1240上的操作与所述接口板1230的操作一致，为了简洁，不再赘述。应理解，本实施例的第一PE设备1200可对应于上述方法实施例所具有的功能和/或所实施的各种步骤，在此不再赘述。
此外，需要说明的是，主控板可能有一块或多块，有多块的时候可以包括主用主 控板和备用主控板。接口板可能有一块或多块，第一PE设备的数据处理能力越强，提供的接口板越多。接口板上的物理接口卡也可以有一块或多块。交换网板可能没有，也可能有一块或多块，有多块的时候可以共同实现负荷分担冗余备份。在集中式转发架构下，第一PE设备可以不需要交换网板，接口板承担整个系统的业务数据的处理功能。在分布式转发架构下，第一PE设备可以有至少一块交换网板，通过交换网板实现多块接口板之间的数据交换，提供大容量的数据交换和处理能力。所以，分布式架构的第一PE设备的数据接入和处理能力要大于集中式架构的设备。具体采用哪种架构，取决于具体的组网部署场景，此处不做任何限定。
另外，本申请实施例提供了一种计算机存储介质，用于储存为上述第一PE设备所用的计算机软件指令，其包含用于执行上述方法实施例所设计的程序。
本申请实施例还包括一种EVPN系统，所述EVPN系统包括第一PE设备，所述第一PE设备为前述图4或图5或图6中的第一PE设备。
结合本申请公开内容所描述的方法或者算法的步骤可以硬件的方式来实现，也可以是由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于RAM存储器、闪存、ROM存储器、EPROM存储器、EEPROM存储器、寄存器、硬盘、移动硬盘、CD-ROM或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于用户设备中。当然，处理器和存储介质也可以作为分立组件存在于用户设备中。
本领域技术人员应该可以意识到，在上述一个或多个示例中，本申请所描述的功能可以用硬件或者用硬件和软件的组合来实现。当使用硬件和软件的组合实现时，可以将这些软件存储在计算机可读介质中或者作为计算机可读介质上的一个或多个指令或代码进行传输。计算机可读介质包括计算机存储介质和通信介质，其中通信介质包括便于从一个地方向另一个地方传送计算机程序的任何介质。存储介质可以是通用或专用计算机能够存取的任何可用介质。
以上所述的具体实施方式，对本申请的目的、技术方案和有益效果进行了进一步详细说明。所应理解的是，以上所述仅为本申请的具体实施方式而已。

Claims (27)

  1. 一种确定组播流的指定转发者DF的方法，其特征在于，所述方法应用在以太网虚拟专用网络EVPN中，所述EVPN包括第一运营商边缘PE设备、第二PE设备和用户边缘CE设备，所述CE设备经由第一以太网链路与所述第一PE设备连接，所述CE设备经由第二以太网链路与所述第二PE设备连接，所述第一以太网链路和所述第二以太网链路属于同一个以太网段ES，所述方法包括：
    所述第一PE设备接收第一加入报文，所述第一加入报文用于指示所述CE设备请求加入到接收第一组播流的第一组播组中，所述第一组播流是所述EVPN的组播源向所述第一组播组中的组播组成员传输的组播流；
    所述第一PE设备根据所述第一加入报文将所述CE设备加入到所述第一组播组；
    所述第一PE设备确定第一比率是否小于第二比率，其中，所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示所述第一以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示所述第一以太网链路上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示所述第二以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示所述第二以太网链路上可分配给组播业务的总带宽；
    当所述第一PE设备确定所述第一比率小于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的指定转发者DF；
    响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的DF，所述第一PE设备为所述第一组播流分配带宽。
  2. 如权利要求1所述的方法，其特征在于，所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所述第三PE设备连接，所述第三以太网链路属于所述ES，在所述第一PE设备确定第一比率是否小于第二比率之前，所述方法还包括：
    所述第一PE设备确定第一比率小于第三比率，其中，所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示所述第三以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第三链路带宽指示所述第三以太网链路上可分配给组播业务的总带宽。
  3. 如权利要求1或2所述的方法，其特征在于，所述方法还包括：
    当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的非指定转发者non-DF；
    响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽。
  4. 如权利要求1或2所述的方法，其特征在于，所述方法还包括：
    当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一PE设备的互联网协议IP地址的值大于所述第二PE设备的IP地址的值时，所述第一PE设备确定所述第一 PE设备是所述第一组播流的DF。
  5. 如权利要求1或2所述的方法，其特征在于，所述方法还包括：
    当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述第一PE设备确定所述第一链路带宽大于所述第二链路带宽时，所述第一PE设备确定所述第一PE设备是所述第一组播流的DF。
  6. 如权利要求1或2所述的方法，其特征在于，所述方法还包括：
    当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，所述第一PE设备根据哈希Hash算法确定所述第一PE设备是所述第一组播流的DF。
  7. 如权利要求1-6中任一项所述的方法，其特征在于，在所述第一PE设备确定第一比率是否小于第二比率之前，所述方法还包括：
    所述第一PE设备接收所述第二PE设备发送的第二以太网段路由，所述第二以太网段路由包括第二链路带宽扩展团体属性，所述第二链路带宽扩展团体属性用于携带所述第二链路带宽；
    所述第一PE设备向所述第二PE设备发送第一以太网段路由，所述第一以太网段路由包括第一链路带宽扩展团体属性，所述第一链路带宽扩展团体属性用于携带所述第一链路带宽。
  8. 如权利要求1-7中任一项所述的方法，其特征在于，所述第一加入报文是所述CE设备发送的组播组加入报文。
  9. 如权利要求8所述的方法，其特征在于，所述方法还包括：
    所述第一PE设备向所述第二PE设备发送第一加入同步路由，所述第一加入同步路由用于指示所述CE设备请求加入到接收所述第一组播流的所述第一组播组中。
  10. 如权利要求9所述的方法，其特征在于，所述第一加入同步路由包括第一组播DF扩展团体属性，所述第一组播DF扩展团体属性携带作为所述第一组播流的DF的PE设备的IP地址。
  11. 如权利要求1-7中任一项所述的方法，其特征在于，所述第一加入报文是所述第二PE设备发送的第二加入同步路由。
  12. 如权利要求2所述的方法，其特征在于，所述方法还包括：
    所述第一PE设备根据接收的、来自所述第三PE设备的第一以太网自动发现每以太网段路由的撤销消息，确定所述第三以太网链路退出所述ES，其中，所述撤销消息指示所述第三PE设备撤销所述第一以太网自动发现每以太网段路由；
    所述第一PE设备根据所述第一链路带宽和所述第二链路带宽，或者所述第一PE 设备根据所述第一PE设备的IP地址的值和所述第二PE设备的IP地址的值，确定作为第二组播流的DF的PE设备，其中，在所述第三以太网链路退出所述ES之前，所述第二组播流的DF是所述第三PE设备，所述第二组播流是所述EVPN的组播源向第二组播组中的组播组成员传输的组播流，所述CE设备是所述第二组播组中的组播组成员；
    所述第一PE设备向所述第二PE设备发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带作为所述第二组播流的DF的PE设备的IP地址。
  13. 如权利要求1中所述的方法，其特征在于，所述方法还包括：
    当所述第一PE设备确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF；
    响应于所述第一PE设备确定所述第一PE设备是所述第一组播流的non-DF，所述第一PE设备不为所述第一组播流分配带宽；
    所述第一PE设备根据接收的、来自所述第四PE设备的第二以太网自动发现每以太网段路由，确定第四以太网链路加入所述ES，所述CE设备经由所述第四以太网链路与所述第四PE设备连接；
    所述第一PE设备将作为第三组播流的DF的PE设备由所述第一PE设备变更为所述第四PE设备，所述第三组播流是所述EVPN的组播源向第三组播组中的组播组成员传输的组播流，所述CE设备是所述第三组播组中的组播组成员；
    所述第一PE设备向所述第二PE设备和所述第四PE设备发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF扩展团体属性，所述第三组播DF扩展团体属性携带所述第四PE设备的IP地址。
  14. 一种第一运营商边缘PE设备，其特征在于，所述第一PE设备应用在以太网虚拟专用网络EVPN中，所述EVPN还包括第二PE设备和用户边缘CE设备，所述CE设备经由第一以太网链路与所述第一PE设备连接，所述CE设备经由第二以太网链路与所述第二PE设备连接，所述第一以太网链路和所述第二以太网链路属于同一个以太网段ES，所述第一PE设备包括：
    接收器，用于接收第一加入报文，所述第一加入报文用于指示所述CE设备请求加入到接收第一组播流的第一组播组中，所述第一组播流是所述EVPN的组播源向所述第一组播组中的组播组成员传输的组播流；
    处理器，用于根据所述第一加入报文将所述CE设备加入到所述第一组播组；
    所述处理器还用于确定第一比率是否小于第二比率，其中，所述第一比率是第一分配带宽和第一链路带宽的比率，所述第一分配带宽指示所述第一以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第一链路带宽指示所述第一以太网链路上可分配给组播业务的总带宽，所述第二比率是第二分配带宽和第二链路带宽的比率，所述第二分配带宽指示所述第二以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第二链路带宽指示所述第二以太网链路上可分配给组播业务的总带宽；
    当所述处理器确定所述第一比率小于所述第二比率时，所述处理器还用于确定所述第一PE设备是所述第一组播流的指定转发者DF；
    响应于所述处理器确定所述第一PE设备是所述第一组播流的DF，所述处理器还用于为所述第一组播流分配带宽。
  15. 如权利要求14所述的第一PE设备，其特征在于，所述EVPN还包括第三PE设备，所述CE设备经由第三以太网链路与所述第三PE设备连接，所述第三以太网链路属于所述ES，在所述处理器确定第一比率是否小于第二比率之前，所述处理器还用于确定第一比率小于第三比率，其中，所述第三比率是第三分配带宽和第三链路带宽的比率，所述第三分配带宽指示所述第三以太网链路上可分配给组播业务的总带宽中已分配的带宽，所述第三链路带宽指示所述第三以太网链路上可分配给组播业务的总带宽。
  16. 如权利要求14或15所述的第一PE设备，其特征在于，
    当所述处理器确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述处理器还用于确定所述第一PE设备是所述第一组播流的非指定转发者non-DF；
    响应于所述处理器确定所述第一PE设备是所述第一组播流的non-DF，所述处理器还用于不为所述第一组播流分配带宽。
  17. 如权利要求14或15所述的第一PE设备，其特征在于，
    当所述处理器确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述处理器确定所述第一PE设备的互联网协议IP地址的值大于所述第二PE设备的IP地址的值时，所述处理器还用于确定所述第一PE设备是所述第一组播流的DF。
  18. 如权利要求14或15所述的第一PE设备，其特征在于，
    当所述处理器确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，并且，当所述处理器确定所述第一链路带宽大于所述第二链路带宽时，所述处理器还用于确定所述第一PE设备是所述第一组播流的DF。
  19. 如权利要求14或15所述的第一PE设备，其特征在于，
    当所述处理器确定所述第一比率不小于所述第二比率，以及所述第一比率等于所述第二比率时，所述处理器还用于根据哈希Hash算法确定所述第一PE设备是所述第一组播流的DF。
  20. 如权利要求14-19中任一项所述的第一PE设备，其特征在于，所述第一PE设备还包括发送器，在所述处理器确定第一比率是否小于第二比率之前，
    所述接收器还用于接收所述第二PE设备发送的第二以太网段路由，所述第二以太网段路由包括第二链路带宽扩展团体属性，所述第二链路带宽扩展团体属性用于携 带所述第二链路带宽；
    所述发送器，用于向所述第二PE设备发送第一以太网段路由，所述第一以太网段路由包括第一链路带宽扩展团体属性，所述第一链路带宽扩展团体属性用于携带所述第一链路带宽。
  21. 如权利要求14-19中任一项所述的第一PE设备，其特征在于，所述第一加入报文是所述CE设备发送的组播组加入报文。
  22. 如权利要求21所述的第一PE设备，其特征在于，所述第一PE设备还包括发送器，
    所述发送器，用于向所述第二PE设备发送第一加入同步路由，所述第一加入同步路由用于指示所述CE设备请求加入到接收所述第一组播流的所述第一组播组中。
  23. 如权利要求22所述的第一PE设备，其特征在于，所述第一加入同步路由包括第一组播DF扩展团体属性，所述第一组播DF扩展团体属性携带作为所述第一组播流的DF的PE设备的IP地址。
  24. 如权利要求14-20中任一项所述的第一PE设备，其特征在于，所述第一加入报文是所述第二PE设备发送的第二加入同步路由。
  25. 如权利要求15所述的第一PE设备，其特征在于，所述第一PE设备还包括发送器，
    所述处理器还用于根据接收的、来自所述第三PE设备的第一以太网自动发现每以太网段路由的撤销消息，确定所述第三以太网链路退出所述ES，其中，所述撤销消息指示所述第三PE设备撤销所述第一以太网自动发现每以太网段路由；
    所述处理器还用于根据所述第一链路带宽和所述第二链路带宽，或者所述第一PE设备根据所述第一PE设备的IP地址的值和所述第二PE设备的IP地址的值，确定作为第二组播流的DF的PE设备，其中，在所述第三以太网链路退出所述ES之前，所述第二组播流的DF是所述第三PE设备，所述第二组播流是所述EVPN的组播源向第二组播组中的组播组成员传输的组播流，所述CE设备是所述第二组播组中的组播组成员；
    所述发送器，用于向所述第二PE设备发送所述第二组播流对应的第三加入同步路由，所述第三加入同步路由包括第二组播DF扩展团体属性，所述第二组播DF扩展团体属性携带作为所述第二组播流的DF的PE设备的IP地址。
  26. 如权利要求14中所述的第一PE设备，其特征在于，所述第一PE设备还包括发送器，
    当所述处理器确定所述第一比率不小于所述第二比率，以及所述第一比率大于所述第二比率时，所述处理器还用于确定所述第一PE设备是所述第一组播流的non-DF；
    响应于所述处理器确定所述第一PE设备是所述第一组播流的non-DF，所述处理 器还用于不为所述第一组播流分配带宽；
    所述处理器还用于根据接收的、来自所述第四PE设备的第二以太网自动发现每以太网段路由，确定第四以太网链路加入所述ES，所述CE设备经由所述第四以太网链路与所述第四PE设备连接；
    所述处理器还用于将作为第三组播流的DF的PE设备由所述第一PE设备变更为所述第四PE设备，所述第三组播流是所述EVPN的组播源向第三组播组中的组播组成员传输的组播流，所述CE设备是所述第三组播组中的组播组成员；
    所述发送器，用于向所述第二PE设备和所述第四PE设备发送所述第三组播流对应的第四加入同步路由，所述第四加入同步路由包括第三组播DF扩展团体属性，所述第三组播DF扩展团体属性携带所述第四PE设备的IP地址。
  27. 一种以太网虚拟专用网络EVPN系统，其特征在于，所述EVPN系统包括第一PE设备，所述第一PE设备为权利要求14至26中任一所述的第一PE设备。
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