WO2013056633A1 - 在组播源切换场景下建立优化路径的方法及系统 - Google Patents

在组播源切换场景下建立优化路径的方法及系统 Download PDF

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Publication number
WO2013056633A1
WO2013056633A1 PCT/CN2012/082854 CN2012082854W WO2013056633A1 WO 2013056633 A1 WO2013056633 A1 WO 2013056633A1 CN 2012082854 W CN2012082854 W CN 2012082854W WO 2013056633 A1 WO2013056633 A1 WO 2013056633A1
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multicast
mag
tunnel
belongs
target
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PCT/CN2012/082854
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English (en)
French (fr)
Inventor
刘娟
严为
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中兴通讯股份有限公司
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Publication of WO2013056633A1 publication Critical patent/WO2013056633A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/40—Connection management for selective distribution or broadcast
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/12—Setup of transport tunnels

Definitions

  • the present invention relates to the field of mobile communications, and in particular, to a method and system for establishing an optimized path in a multicast source switching scenario.
  • Multicast is to solve the efficiency problem that traditional unicast routing occurs when dealing with group communication.
  • IGMP Internet Group Management Protocol
  • MLD Multicast Listener Discovery Protocol
  • Mobility management protocols such as mobile IP.
  • IP multicast service models There are two types of IP multicast service models: Any Source Multicast ASM (full name Any-Source Multicast) and a specific source multicast SSM (full name Source-Specific Multicast).
  • ASM uses a multicast group address G to identify a multicast group. Each multicast group can have any number of multicast sources and receivers.
  • the aggregation point (RP, called Rendezvous Point) is used for the shared tree.
  • each channel can only have one specified source and any number of receivers. There is no need to select the aggregation point RP and the maintenance shared tree (RPT) in the SSM model.
  • the multicast source is registered, so that the SPT with the multicast source S as the root and the receiver as the leaf is directly constructed in the network, thereby eliminating the process of establishing the shared tree and then switching from the shared tree to the shortest path tree in the ASM model.
  • SSM is a simple and effective multicast model, which can overcome the shortcomings of ASM in access control, address allocation, source discovery, and vulnerability to DoS attacks. Therefore, SSM model is more scalable and can be used. Improve network performance in the future The Internet has a wider application prospect.
  • RPF reverse path forwarding
  • the RPF check process is as follows: The router that receives the multicast packet searches for the unicast routing table with the IP address of the multicast source as the destination address. The outbound interface in the corresponding entry is the RPF interface. The router considers that the RPF is configured by the RPF. The path that the multicast packet received by the interface is the shortest path from the multicast source to the local device. The RPF interface is compared with the interface where the multicast packet actually arrives.
  • the unicast routing information used as the basis for path judgment can be derived from any unicast routing protocol, multicast static route, or MBGP routing protocol.
  • the multicast receiver MN It is located in the same ⁇ domain as the multicast source MN-S (MN-Source).
  • MN-Source multicast source MN-S
  • the multicast source MN-S is currently connected to the mobile access gateway P-MAG, and is connected to the mobile access gateway MAG, MN and MN-
  • the top anchor of S can be the same LMA or a different LMA.
  • the MN reports to the MAG through the MLDv2 report message that it needs to receive multicast data from the multicast source MN-S and sent to the multicast group G.
  • the MAG sends the channel subscription packet to the multicast source MN-S.
  • the subscription packet sent by the MAG to the LMA needs to be encapsulated in the tunnel.
  • the subscription message sent by the LMA to the P-MAG is also Tunnel encapsulation is required. All routers along the way create (HoA, G) multicast routing entries. HoA represents the address of the multicast source MN-S, and G represents the multicast address. Therefore, the multicast source MN-S is used as the root.
  • the path from the P-MAG to the LMA to which the multicast source MN-S belongs is a PMIPv6 tunnel, and the path from the LMA to the MAG to which the MN belongs is a PMIPv6 tunnel, and then the multicast source MN-
  • the multicast data sent by S reaches the MN along the established SPT, and the multicast forwarding path is as shown in 100a of FIG.
  • the MN-S switches to the new mobile access gateway N-MAG, a new SPT path is established through the above process, as shown in 101a of FIG.
  • the path from the N-MAG to the LMA to which the multicast source MN-S belongs is a PMIPv6 tunnel
  • the path from the LMA to the MAG to which the MN belongs is a PMIPv6 tunnel.
  • the multicast message sent by the MN-S to the MN must first be sent through the PMIPv6 tunnel between the MN-S mobile access gateway MAG and the local mobility anchor (LMA), and the multicast message arrives.
  • the LM's mobility anchor LMA it must be sent through the PMIPv6 tunnel between the LMA and the MN's mobile access gateway. Therefore, the SPT paths 100a and 101a shown in FIG. 1a are not the shortest multicast forwarding path, and the multicast routing is reduced. s efficiency.
  • the multicast receiver MN When the multicast source MN-S is switched, the multicast receiver MN does not know the switching event of the multicast source, causing serious packet loss, and the entire multicast forwarding tree needs to be reconstructed after the multicast source is switched. Large multicast protocol overhead and network load. Therefore, the current mobile multicast solution proposed based on PMIPv6 inevitably causes non-shortest SPT paths and multicast handover packet loss, which reduces routing efficiency and mobile multicast performance.
  • the embodiments of the present invention provide a method and system for establishing an optimized path in a multicast source switching scenario, which solves the problem of low routing efficiency caused by a non-shortest SPT path in a multicast source switching scenario in the existing solution.
  • the present invention provides a method for establishing an optimized path in a multicast source switching scenario, including:
  • the target mobile access gateway (MAG) of the multicast source (MN-S) learns the multicast service information of the MN-S from the source MAG or the local mobility anchor (LMA) of the MN-S, according to the MN
  • the multicast service information of the -S establishes a multicast tunnel with the MAG to which the multicast receiver (MN) belongs, and the target MAG sends the multicast message of the MN-S to the MN through the multicast tunnel.
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, and an address of the MAG to which the MN belongs, including an address of one or more MAGs.
  • the step of establishing a multicast tunnel between the target MAG and the MAG to which the MN belongs includes: after the target MAG establishes a tunnel interface to the MAG to which the MN belongs, according to the address of the multicast source in the multicast service information, The multicast group entry creates a multicast routing entry, and adds the tunnel interface to the MAG to which the MN belongs to the outbound interface list of the multicast routing entry.
  • the step of establishing a multicast tunnel between the target MAG and the MAG to which the MN belongs includes: Sending, by the target MAG, a multicast tunnel setup message to the MAG to which the MN belongs, and carrying the address of the MN-S and the inbound interface update flag for indicating the update of the inbound interface of the multicast routing entry;
  • the MAG to which the MN belongs After receiving the multicast tunnel establishment message, the MAG to which the MN belongs sets up an interface to the bidirectional tunnel of the target MAG, searches for and updates the corresponding multicast routing entry according to the address of the MN-S, and sets the group.
  • the ingress interface of the broadcast routing entry is set to the tunnel interface to the target MAG of the MN-S.
  • the step of the target MAG transmitting the multicast of the MN-S to the MAG to which the MN belongs includes:
  • the target MAG After receiving the multicast file sent by the MN-S, the target MAG sends the multicast message to all multicast tunnel interfaces in the outbound interface list of the maintained multicast routing entry.
  • the method also includes:
  • the MAG to which the MN belongs After receiving the multicast message through the multicast tunnel, the MAG to which the MN belongs determines that the multicast tunnel interface that receives the multicast packet is the inbound interface of the maintained multicast routing entry, and sends the multicast route to the multicast route. All outbound interfaces in the outbound interface list of the item are forwarded.
  • the target MAG obtains the multicast service information of the MN-S from the source MAG by using an extended handover initiation message, including:
  • the MN-S reports the identifier of the MN-S and the target access network identifier to the source access network, and the source access network sends the identifier carrying the MN-S and the target access network identifier to the source MAG.
  • the switching indication information, the source MAG determines an address of the target MAG according to the target access network identifier, and sends an extended handover initiation message to the target MAG, where the extended handover initiation message carries the MN-S Multicast service information.
  • the target MAG obtains the multicast service information of the MN-S from the source MAG by using an extended handover confirmation message, including:
  • the target MAG After the MN-S establishes a connection with the target MAG via the target access network, the target MAG sends a handover initiation message to the source MAG, and when the source MAG returns an extended handover confirmation message to the target MAG, the extended handover confirmation is performed.
  • the message carries the multicast service information of the MN-S.
  • the target MAG obtains the multicast service information of the MN-S from the LMA by using an extended binding acknowledgement message, including: After the MN-S leaves the source MAG, the source MAG sends an extended deregistration binding update message to the LMA, where the message carries the multicast service information of the MN-S, and the LMA saves Multicast service information of the MN-S;
  • the target MAG After the MN-S switches to the target MAG, the target MAG sends a binding acknowledgement message to the LMA to carry the multicast service information of the MN-S.
  • the target MAG obtains the multicast service information of the MN-S from the LMA by using an extended binding acknowledgement message, including:
  • the source MAG synchronizes the multicast service information of the MN-S to the LMA while creating a multicast routing entry
  • the target MAG After the MN-S is handed over to the target MAG, the target MAG sends an extended binding acknowledgement message to the LMA to carry the multicast service information of the MN-S.
  • the method further includes: when the MN no longer receives the multicast message of the MN-S, the MAG to which the MN belongs sends a statement to the MAG to which the MN-S belongs to exit with the address of the MN-S as a prune message of the target address, and deleting the multicast routing entry corresponding to the MN-S, and removing the multicast tunnel to the MAG to which the MN-S belongs;
  • the embodiment of the present invention further provides a system for establishing an optimized path in a multicast source switching scenario, including a multicast source (MN-S), a target mobile access gateway (MAG) of the MN-S, and a source MAG of the MN-S. , the local mobility anchor (LMA) and the MAG to which the multicast receiver (MN) belongs;
  • MN-S multicast source
  • MAG target mobile access gateway
  • LMA local mobility anchor
  • MN multicast receiver
  • the target MAG is configured to: learn the multicast service information of the MN-S from the source MAG or the local mobility anchor (LMA) of the MN-S, according to the multicast service information of the MN-S and the The MAG to which the MN belongs establishes a multicast tunnel, and the multicast message of the MN-S is sent to the MAG to which the MN belongs.
  • LMA local mobility anchor
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, And the address of the MAG to which the MN belongs, including the address of one or more MAGs.
  • the target MAG is configured to establish a multicast tunnel by creating a multicast according to the address and multicast group address of the multicast source in the multicast service information after establishing a tunnel interface to the MAG to which the MN belongs.
  • the routing entry adds the tunnel interface to the MAG to which the MN belongs to the outbound interface list of the multicast routing entry.
  • the target MAG is configured to establish a multicast tunnel by: sending a multicast tunnel setup message to the MAG to which the MN belongs, and carrying the address of the MN-S and indicating the update of the multicast route in the message.
  • the MAG to which the MN belongs is set to establish a multicast tunnel with the target MAG to which the MN-S belongs by: after receiving the multicast tunnel establishment message, establishing an interface to the bidirectional tunnel of the target MAG, according to The address of the MN-S searches for and updates the corresponding multicast routing entry, and sets the inbound interface of the multicast routing entry to the tunnel interface of the target MAG of the MN-S.
  • the target MAG is configured to send the multicast message of the MN-S to the MAG to which the MN belongs: after receiving the multicast message sent by the MN-S, to the maintained group. All multicast tunnel interfaces in the outbound interface list of the broadcast routing entry send the multicast packet.
  • the MAG to which the MN belongs is further configured to: after receiving the multicast packet through the multicast tunnel, determine that the multicast tunnel interface that receives the multicast packet is the inbound interface in the maintained multicast routing entry, The multicast packet is forwarded to all outbound interfaces in the outbound interface list of the multicast routing entry.
  • the embodiment of the present invention further provides a mobile access gateway, including a multicast processing module, where the multicast processing module is configured to: use a mobile access gateway (MAG) as a multicast source
  • MAG mobile access gateway
  • MN-S when the target MAG is obtained, the multicast service information of the MN-S is obtained from the source MAG or the local mobility anchor (LMA) of the MN-S, and the multicast service information according to the MN-S is obtained. Establishing a multicast tunnel with the MAG to which the multicast receiver (MN) belongs, and transmitting the multicast information of the MN-S to the MAG to which the MN belongs.
  • LMA local mobility anchor
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, and an address of the MAG to which the MN belongs, including an address of one or more MAGs.
  • the multicast processing module is configured to establish a multicast tunnel by: after establishing the tunnel interface of the target MAG to the MAG to which the MN belongs, according to the multicast service information
  • the multicast source address and the multicast group address are used to create a multicast routing entry, and the tunnel interface of the target MAG to the MAG to which the MN belongs is added to the outbound interface list of the multicast routing entry.
  • the multicast processing module is configured to establish a multicast tunnel with the MAG to which the MN belongs by: sending a multicast tunnel setup message to the MAG to which the MN belongs, and carrying the MN-S in the message.
  • An address and an inbound interface update flag for indicating an update of the multicast routing entry interface;
  • the multicast processing module is further configured to: when the associated MAG is the MAG to which the MN belongs, after receiving the multicast tunnel establishment message, establish an interface to the bidirectional tunnel of the target MAG, according to the MN- The address of the S is searched for and updated with the corresponding multicast routing entry, and the inbound interface of the multicast routing entry is set to the tunnel interface of the MAG to which the MN belongs to the target MAG of the MN-S.
  • the multicast processing module is configured to send the multicast message of the MN-S to the MAG to which the MN belongs: after receiving the multicast message sent by the MN-S, All multicast tunnel interfaces in the outbound interface list of the multicast routing entry send the multicast packet.
  • the multicast processing module is further configured to: when the associated MAG is the MAG to which the MN belongs, after receiving the multicast packet through the multicast tunnel, determine that the multicast tunnel interface that receives the multicast packet is When the inbound interface of the multicast routing entry is maintained, the multicast packet is forwarded to all outbound interfaces in the outbound interface list of the multicast routing entry.
  • the method for establishing an SPT path provided by the solution can improve the routing efficiency and the performance of the mobile multicast in the handover process of the multicast receiving end.
  • FIG. 1 is a schematic diagram of a scenario in which a multicast switchover is performed in a PMIPv6 domain in the prior art
  • FIG. 2B is a schematic diagram of a scenario in which a multicast source is switched in a PMIPv6 domain in the embodiment
  • FIG. 3 is a flowchart of a method for quickly establishing an optimized SPT path when a multicast source is switched according to Embodiment 2; 4 is a flowchart of a method for quickly establishing an optimized SPT path when a multicast source is switched in a third embodiment;
  • FIG. 5 is a flowchart of a method for registering multicast service information with a multicast source to a LMA according to a fourth embodiment
  • FIG. 5B is a flow chart of a method for rapidly establishing an optimized SPT path when a multicast source is switched according to a fourth embodiment.
  • a method for establishing an optimized path in a multicast source switching scenario including: a target mobile access gateway (MAG) of a multicast source (MN-S) is learned from a source MAG or a local mobility anchor (LMA) of the MN-S
  • the multicast service information of the MN-S establishes a multicast tunnel with the MAG to which the multicast receiver (MN) belongs according to the multicast service information of the MN-S, where the target MAG groups the MN-S
  • the broadcast message is sent to the MAG to which the MN belongs through the multicast tunnel.
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, a peer MAG address, that is, an address of the MAG to which the MN belongs, and the peer MAG address includes one or more The address of the MAG.
  • Figure lb shows the scenario of the multicast source switching in the PMIPv6 domain.
  • MN-S represents the multicast source
  • P-MAG is the mobile access gateway before MN-S handover
  • N-MAG is the mobility after MN-S handover.
  • the access gateway is the mobile access gateway of the multicast receiver MN.
  • a set of mobile access gateways MAG is shown, and a group of multicast receivers MN are connected.
  • the MN reports to the MAG through the MLDv2 report message that it needs to receive multicast data from the multicast source MN-S and sent to the multicast group G.
  • the MAG queries the LMA for the P-MAG address information based on the multicast source address HoA, and establishes a tunnel between the P-MAG and the MAG.
  • the MAG sends a channel subscription to the multicast source MN-S through the tunnel.
  • HoA represents the address of the multicast source MN-S
  • G represents the multicast address, thus constructing the multicast source MN-S as the root to multicast
  • the recipient MN is the optimized SPT path for the leaf, as shown at 100b of Figure lb.
  • the target MAG when the MN-S is switched, a method flow for optimizing the SPT path is quickly established, and the optimized SPT path is as shown in 101b of FIG.
  • the target MAG after the target MAG establishes a tunnel interface to the MAG to which the MN belongs, a multicast routing entry is created according to the multicast source address and the multicast group address in the multicast service information, and the target MAG is obtained.
  • the tunnel interface of the MAG to which the MN belongs is added to the outbound interface list of the multicast routing entry.
  • the target MAG Transmitting, by the target MAG, a multicast tunnel setup message to the MAG to which the MN belongs, and carrying the address of the MN-S and an inbound interface update identifier for instructing to update the inbound interface of the multicast routing entry
  • the MAG to which the MN belongs sets up an interface to the bidirectional tunnel of the target MAG, and searches for and updates the corresponding multicast routing entry according to the address of the MN-S, and the multicast routing entry is used.
  • the inbound interface is set to the tunnel interface of the MAG to which the MN belongs to the target MAG of the MN-S.
  • the target MAG After receiving the multicast file sent by the MN-S, the target MAG sends the multicast packet to all multicast tunnel interfaces in the outbound interface list of the maintained multicast routing entry.
  • the MAG to which the MN belongs After receiving the multicast message through the multicast tunnel, the MAG to which the MN belongs determines that the multicast tunnel interface that receives the multicast packet is the inbound interface of the multicast routing entry, and the outgoing interface to the multicast routing entry All outbound interfaces in the list are forwarded.
  • the target MAG learns the multicast service information of the MN-S from the source MAG by using an extended handover initiation message, and the MN-S reports the MN to the source access network.
  • the identifier of the S and the target access network identifier the source access network sends, to the source MAG, a handover indication information that carries the identifier of the MN-S and the identifier of the target access network, where the source MAG is based on the target access network.
  • the identifier determines the address of the target MAG, and sends an extended handover initiation message to the target MAG, where the extended handover initiation message carries the multicast service information of the MN-S.
  • the specific implementation method of Embodiment 1 includes the following steps:
  • Step 200 The MN-S sends a multicast message to the MN by optimizing the SPT path. As shown in step 200b, the multicast data is sent through a tunnel between the P-MAG and the MAG.
  • Step 201 The MN-S detects that it needs to perform MAG handover, and then reports its own ID and the new access point identifier AP-ID to the previous access network P-AN (ie, the connection before the MN-S handover). Enter The internet).
  • Step 202 After receiving the report message from the MN-S, the P-AN sends a handover indication message to the source mobile access gateway P-MAG (ie, the currently connected mobile access gateway of the MN-S), in the message.
  • P-MAG the currently connected mobile access gateway of the MN-S
  • the MN-ID carrying the multicast source and the new access point identity AP-ID are also carried.
  • Step 203 The P-MAG obtains the address information of the new mobile access gateway N-MAG according to the new access point identifier AP-ID in the handover indication message, and sends a handover initiation message HI to the N-MAG.
  • the multicast service information of the MN-S is carried in the message, and the multicast service information includes multiple records, each record includes (HoA, G, peer MAG address), HoA represents the address of the multicast source, and G represents the group.
  • the broadcast group address, the peer MAG address represents the address of the mobile access gateway of the multicast receiver MN, which may be the address of one or more MAGs.
  • this example uses a peer MAG as an example. (There may be multiple peer MAGs in an actual deployment.)
  • the content included in the multicast service information is not limited to the above fields, and other fields may be added as needed in the actual application.
  • Step 204 The N-MAG sends a handover confirmation message HAck to the P-MAG as an acknowledgement of the handover initiation message HI.
  • the scheme defines a pair of new mobile header messages, Proxy Multicast Tunnel (PMT) and Proxy Multicast Tunnel Reply (PMTR) as messages for establishing a multicast tunnel, and can also extend PBU/ The PBA (Proxy Binding Update/Proxy Binding Acknowledgement) message serves as a message for establishing a multicast tunnel.
  • Proxy Multicast Tunnel PMT
  • Proxy Multicast Tunnel Reply PMTR
  • Step 205 The N-MAG sends the MAG address to the MAG according to the peer MAG address in the multicast service information.
  • the PMT message requests to establish a multicast tunnel with the MAG.
  • the PMT message carries the address HoA of the multicast source and the inbound interface update flag for instructing the update of the inbound interface of the multicast routing entry.
  • the PMT message can carry two new mobile options: The source address option and the inbound interface update option.
  • the multicast source address option is used to carry the address of the multicast source.
  • the inbound interface update option is used to notify the peer MAG to update the inbound interface of the multicast routing entry.
  • Step 206 After receiving the PMT message, the MAG sends a proxy multicast tunnel establishment response message PMTR to the N-MAG, and establishes an interface to the N-MAG bidirectional tunnel.
  • Step 207 The MAG updates the option and the multicast source address option according to the inbound interface in the PMT message.
  • the multicast routing entry is updated.
  • the MAG searches for the local multicast routing entry based on the multicast source address and updates the inbound interface of the multicast routing entry to the tunnel interface of the MAG to the N-MAG.
  • Step 208 After receiving the PMTR message, the N-MAG establishes an interface to the bidirectional tunnel of the MAG, and creates a multicast routing entry according to the multicast source address and the multicast group address in the multicast service information, and the N-MAG is sent to the MAG.
  • the tunnel interface is added to the outbound interface list of multicast routing entries.
  • the bidirectional multicast tunnel between the N-MAG and the MAG is established, and the bidirectional tunnel is used to carry the multicast control packet and the multicast data packet.
  • Step 210 The MN-S establishes a connection with the new access network N-AN.
  • Step 211 The new access network N-AN establishes a connection with the new mobile access gateway N-MAG.
  • Step 213 After receiving the multicast packet, the N-MAG searches for the multicast routing entry and sends the multicast packet to all the interfaces in the outbound interface list. As shown in step 208, the new tunnel interface is saved in the outbound interface list. The N-MAG encapsulates the multicast packet and sends it to the remote MAG.
  • Step 214 After decapsulating the packet, the MAG searches for the multicast routing entry, and sends the multicast packet to all the interfaces in the outbound interface list. The MN then receives the multicast packet. In step 207, the interface that the MAG receives the multicast packet matches the inbound interface saved in the multicast routing entry, and forwards the multicast packet to all the outbound interfaces. If the MAG does not update the routing entry in step 207 in time, If the interface that receives the multicast packet (the tunnel interface established with the N-MAG) does not match the inbound interface (the tunnel interface established with the P-MAG) that is saved in the multicast routing entry, the MAG performs RPF on the multicast packet.
  • the MAG performs RPF on the multicast packet.
  • the inbound interface of the MAG update multicast routing entry is the interface that receives the multicast packet (that is, the new tunnel interface). If the interface does not match the interface that receives multicast packets, the interface discards the packet from the wrong path.
  • an optimized SPT path is established in advance, and the routers through which the path passes are generated in the forwarding table.
  • the multicast receiver MN can quickly obtain multicast data by optimizing the SPT path after the MN-S is switched, thereby improving the multicast service quality and multicast forwarding efficiency.
  • the target MAG learns the multicast service information of the MN-S from the source MAG by using an extended handover confirmation message, and includes: the MN-S communicates with the target MAG via a target access network. After the connection is established, the target MAG sends a handover initiation message to the source MAG. When the source MAG returns an extended handover confirmation message to the target MAG, the extended handover confirmation message carries the multicast service information of the MN-S.
  • the specific implementation method of the second embodiment includes:
  • Step 300 The MN-S sends a multicast packet to the MNs by optimizing the SPT path. As shown in step 300b, the multicast data is sent through a tunnel between the P-MAG and the MAG.
  • Step 301 The MN-S switches, and the MN-S establishes a connection with the new access network N-AN.
  • Step 302 The new access network N-AN establishes a connection with the new mobile access gateway N-MAG, and the N-MAG obtains the address information of the P-MAG through the AP-ID of the P-AN.
  • Step 303 The N-MAG sends a handover initiation message to the P-MAG.
  • Step 304 The P-MAG sends a handover confirmation message HAck to the N-MAG, and the HAck message is extended, and the message carries the multicast service information of the MN-S.
  • the content of the multicast service information is the same as that described in step 203.
  • step 305 to step 309 is the same as that of step 205 to step 209, and is not described here.
  • the processing flow of the steps 310 to 312 is the same as that of the step 212 to the step 214, and details are not described herein again.
  • the N-MAG in combination with the post-registration fast handover technology of the PFMIPv6 protocol, in the process of the MN-S switching to the new mobile access gateway N-MAG, the N-MAG pre-establishes the optimized optimization by requesting the multicast service information from the P-MAG.
  • the routers that the path passes through generate the corresponding multicast routing entries in the forwarding table.
  • the multicast receiver MN can quickly obtain multicast data by optimizing the SPT path after the MN-S is switched. Thereby improving the quality of multicast service and multicast forwarding.
  • the target MAG obtains the multicast service information of the MN-S from the LMA by using an extended binding acknowledgement message, including: after the MN-S leaves the source MAG, The multicast service information of the MN-S, the LMA saves the multicast service information of the MN-S; after the MN-S switches to the target MAG, the target MAG sends a binding to the LMA.
  • the message carries the multicast service information of the MN-S.
  • the specific method of Embodiment 3 includes the following steps:
  • Step 400 The MN-S sends a multicast packet to the MNs by optimizing the SPT path. As shown in step 400b, the multicast data is sent through a tunnel between the P-MAG and the MAG.
  • Step 401 The MN-S leaves the current mobile access gateway P-MAG, and the P-MAG sends a De-Registration binding update message with a lifetime time of zero to the LMA.
  • the present invention extends the binding update message, and the message carries the MN.
  • -S multicast service information the content of the multicast service information is the same as described in step 203.
  • Step 402 After receiving the De-Reg message from the P-MAG, the LMA saves the multicast service information carried in the message to the corresponding binding cache entry BCE.
  • Step 403 The LMA sends a binding acknowledgement message to the P-MAG as a confirmation of the De-Reg message.
  • Step 404 The MN-S switches to the new mobile access gateway N-MAG, and the N-MAG sends a binding update message PBU to the LMA.
  • Step 405 The LMA updates the local binding cache entry BCE.
  • the LMA carries the multicast service information saved in the BCE in the PBA message and sends the message to the N-MAG, and deletes the multicast saved in the local BCE. Service Information.
  • the processing flow of the step 406 to the step 410 is the same as that of the step 205 to the step 209, and is not described here.
  • Steps 411 to 413 are the same as the steps of the subsequent multicast packet forwarding, which are the same as the steps 212 to 214 in the first embodiment, and are not described here.
  • the multicast source is switched to the new mobile access gateway by extending the binding update message.
  • the optimized SPT path is quickly established.
  • the routers that the path passes through generate the corresponding multicast routing entries in the forwarding table.
  • the multicast receiver MN can switch after the multicast source is switched.
  • the multicast data is quickly obtained by optimizing the SPT path, thereby improving the multicast service quality and multicast forwarding efficiency.
  • the target MAG obtains the multicast service information of the MN-S from the LMA by using an extended binding acknowledgement message, which includes: the source MAG creates a multicast routing entry, and The multicast service information of the MN-S is synchronized to the LMA; after the MN-S switches to the target MAG, the target MAG sends a binding update message to the LMA, and the LMA is directed to the target The MAG returns an extended binding acknowledgement message, and the extended binding acknowledgement message carries the multicast service information of the MN-S.
  • an extended binding acknowledgement message which includes: the source MAG creates a multicast routing entry, and The multicast service information of the MN-S is synchronized to the LMA; after the MN-S switches to the target MAG, the target MAG sends a binding update message to the LMA, and the LMA is directed to the target The MAG returns an extended binding acknowledgement message, and the extended binding acknowledgement message carries the multicast service information of the MN-S.
  • a method for rapidly establishing an optimized SPT path when the MN is switched is provided for the fourth embodiment.
  • the multicast source stores the multicast service information to the LMA.
  • the MAG-R MAG-Receiver
  • the MAG-S MAG-Source
  • the registration process includes the following steps:
  • Step 500 The MAG-R sends a PIM Join message to the MAG-S through the multicast tunnel.
  • Step 501 The MAG-S creates a multicast routing entry according to the channel information carried in the PIM Join message, and adds the tunnel interface that receives the PIM Join message to the outbound interface list. If the multicast routing entry of the channel exists on the MAG-S, the outbound interface list is updated. The tunnel interface that receives the PIM Join message is added to the outbound interface list.
  • Step 502 The MAG-S synchronizes the multicast service information of the multicast source to the LMA of the multicast source.
  • the synchronization message can be implemented by extending the PBU message, or a new mobile header message can be defined, and the message carries the multicast service information.
  • the multicast service information contains the same content as described in step 203.
  • Step 503 The LMA saves the multicast service information for the multicast source, and the multicast service information can be saved in the The BCE corresponding to the multicast source can also be saved separately.
  • Step 504 If the multicast receiver MN under the MAG-R no longer receives the multicast data from the multicast source MN-S, send a PIM Prune clip to the MN-S mobile access gateway MAG-S through the multicast tunnel. Branch the message and remove the tunnel between the MAG-S.
  • Step 505 After receiving the prune message, the MAG-S updates the corresponding multicast routing entry, removes the tunnel interface that receives the prune message from the outbound interface list, and removes the tunnel between the MAG-R and the MAG-R.
  • Step 506 The MAG-S synchronizes the multicast service information of the multicast source to the LMA of the multicast source.
  • the synchronization message can be implemented by extending the PBU message, or a new mobile header message can be defined, and the message carries the multicast service information.
  • the multicast service information contains the same content as described in step 203.
  • Step 507 The LMA updates the multicast service information of the locally saved MN-S, and deletes the corresponding record from the multicast service information (that is, deletes the related record of the peer MAG that sends the prune message).
  • the multicast service information of the multicast source is saved on the LMA, and the multicast service information of the multicast source can be updated in real time according to the change of the SPT path.
  • Step 500 The MN-S sends a multicast packet to the MNs by optimizing the SPT path, and the multicast data passes the P-MAG as shown in step 500b.
  • a tunnel is sent between the MAG and the MAG.
  • Step 501 The MN-S switches from the current mobile access gateway P-MAG to the new mobile access gateway N-MAG, and the N-MAG sends a binding update message PBU to the LMA.
  • Step 502 After receiving the PBU message from the P-MAG, the LMA updates the corresponding binding cache entry BCE, and carries the multicast service information saved in the BCE in the PBA message and sends the information to the N-MAG.
  • step 503 to step 507 is the same as that of step 205 to step 209, and details are not described herein.
  • Steps 508 to 510 are the same as steps 212 to 214 in the first embodiment, and are not described here.
  • the service information of the intra-domain multicast source is managed by the LMA.
  • the N-MAG quickly obtains the multicast source group from the LMA.
  • the optimized SPT path is quickly established.
  • the routers that the path passes through generate the corresponding multicast routing entries in the forwarding table.
  • the multicast receiver MN can switch after the multicast source is switched.
  • the multicast data is quickly obtained by optimizing the SPT path, thereby improving the multicast service quality and multicast forwarding efficiency.
  • the embodiment of the present invention is directed to the scenario of ⁇ , and uses MLDv2 to perform IPv6 multicast group member management.
  • the technical solution in the present invention is also applicable to the scenario of proxying mobile IPv4, and can be implemented by a person skilled in the art according to the technical solution in the embodiment of the present invention and combined with the prior art scheme in the prior art.
  • the mobile node in the proxy mobile IPv6 joins the multicast group using MLDv2
  • the mobile node in the proxy mobile IPv4 joins the multicast group using IGMPv3.
  • the system for establishing an optimized path in the multicast receiving end handover scenario corresponding to the foregoing method includes a multicast source (MN-S), a target mobile access gateway (MAG) of the MN-S, a source MAG of the MN-S, and a local The mobile anchor point (LMA) and the MAG to which the MN belongs.
  • MN-S multicast source
  • MAG target mobile access gateway
  • LMA local The mobile anchor point
  • the target MAG is configured to: obtain the multicast service information of the MN-S from the source MAG or the local mobility anchor (LMA) of the MN-S, according to the multicast service information and multicast of the MN-S
  • the MAG to which the receiving end (MN) belongs establishes a multicast tunnel, and the multicast message of the MN-S is sent to the MAG to which the MN belongs.
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, a peer MAG address, that is, an address of the MAG to which the MN belongs, and the peer MAG address includes one or more The address of the MAG.
  • the target MAG is configured to establish a multicast tunnel by creating a multicast route according to the multicast source address and the multicast group address in the multicast service information after establishing a tunnel interface to the MAG to which the MN belongs. Adding a tunnel interface to the MAG to which the MN belongs is added to the outbound interface list of the multicast routing entry.
  • the target MAG is configured to establish a multicast tunnel by: sending a multicast tunnel setup message to the MAG to which the MN belongs, and carrying the address of the MN-S and indicating the update of the multicast route in the message.
  • the MAG to which the MN belongs After receiving the multicast tunnel setup message, the MAG to which the MN belongs sets up an interface to the bidirectional tunnel of the target MAG, and searches for and updates the corresponding multicast routing entry according to the address of the MN-S.
  • the inbound interface of the multicast routing entry is set to the tunnel interface of the target MAG of the MN-S.
  • the target MAG is configured to send the multicast packet to all multicast tunnel interfaces in the outbound interface list of the maintained multicast routing entry after receiving the multicast packet sent by the MN-S.
  • the MAG to which the MN belongs After receiving the multicast message through the multicast tunnel, the MAG to which the MN belongs determines that the multicast tunnel interface that receives the multicast packet is the inbound interface of the multicast routing entry, and the outgoing interface to the multicast routing entry All outbound interfaces in the list are forwarded.
  • the mobile access gateway in this solution includes a multicast processing module.
  • the multicast processing module is configured to: when the mobile access gateway (MAG) is the target MAG of the multicast source (MN-S), learn from the source MAG or the local mobility anchor (LMA) of the MN-S.
  • the multicast service information of the MN-S is configured to establish a multicast tunnel with the MAG to which the multicast receiver (MN) belongs according to the multicast service information of the MN-S, and pass the multicast packet of the MN-S. Sending the multicast tunnel to the MAG to which the MN belongs
  • the multicast service information of the MN-S includes: an address of the MN-S, a multicast group address, a peer MAG address, that is, an address of the MAG to which the MN belongs, and the peer MAG address includes one or more The address of the MAG.
  • the multicast processing module is configured to establish a multicast tunnel by: after establishing a tunnel interface to the MAG to which the MN belongs, creating a group according to the multicast source address and the multicast group address in the multicast service information.
  • the routing entry is added to the outbound interface list of the multicast routing entry by the target MAG to the tunnel interface of the MAG to which the MN belongs.
  • the multicast processing module is further configured to: establish a multicast tunnel in the following manner: when the belonging MAG is the target MAG of the MN-S, send a multicast tunnel establishment message to the MAG to which the MN belongs, and in the message Carrying the address of the MN-S and the inbound interface update flag for instructing to update the inbound interface of the multicast routing entry; and, after receiving the multicast tunnel establishment message, when the belonging MAG is the MAG to which the MN belongs Establishing an interface of the bidirectional tunnel to the target MAG, and searching and updating the corresponding multicast routing entry according to the address of the MN-S, setting the inbound interface of the multicast routing entry to the MAG to which the MN belongs to the MN -S The tunnel interface of the target MAG.
  • the multicast processing module is configured to send the multicast message of the MN-S to the MAG to which the MN belongs: when the belonging MAG is the target MAG of the MN-S, After the multicast packet is sent by the MN-S, the multicast message is sent to all the multicast tunnel interfaces in the outbound interface list of the maintained multicast routing entry.
  • the multicast processing module is further configured to: when the associated MAG is the MAG to which the MN belongs, after receiving the multicast packet through the multicast tunnel, determine that the multicast tunnel interface that receives the multicast packet is a group. When the inbound interface in the routing entry is broadcast, it forwards all the outbound interfaces in the outbound interface list of the multicast routing entry.
  • the execution mode of the multicast processing module is the same as that in the above method, and the description is not repeated here.
  • the method and system for establishing an SPT path provided by the embodiments of the present invention can improve routing efficiency and performance of mobile multicast in a multicast receiving end handover process.

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Abstract

一种在组播源切换场景下建立优化路径的方法及系统，该方法包括：组播源（MN-S）的目标移动接入网关（MAG）从所述MN-S的源MAG或本地移动锚点（LMA）获知所述MN-S的组播服务信息，根据所述MN-S的组播服务信息与组播接收端（MN）所属的MAG建立组播隧道，所述目标MAG将所述MN-S的组播报文通过所述组播隧道发送至所述MN所属的MAG。本方案提供的建立SPT路径的方法可以提高组播接收端切换过程中的路由效率和移动组播的性能。

Description

在组播源切换场景下建立优化路径的方法及系统
技术领域
本发明涉及移动通信领域， 尤其涉及在组播源切换场景下建立优化路径 的方法及系统。
背景技术
组播的出现是为了解决传统单播路由在处理组通信时出现的效率问题。 随着无线和移动技术的发展， 在移动过程中获取组播服务成为了一个研究热 点,移动组播由传统固定组播发展而来， 为移动用户提供诸如移动视频会议、 移动在线游戏等多种应用， 可有效提高数据传输效率。 移动组播需要解决两 个基本问题:一是组成员关系管理， 二是组成员位置管理。 当前组成员关系管 理一般釆用 Internet组管理协议 IGMP (全称为 Internet Group Management Protocol,简称）/组播监听者发现协议 MLD(全称为 Multicast Listener Discovery Protocol )等协议， 而组成员位置管理则釆用移动 IP等移动性管理协议。
IP 组播业务模型分为两种： 任意源组播 ASM (全称为 Any-Source Multicast )和特定源组播 SSM (全称为 Source-Specific Multicast ) 。 ASM模 型使用一个组播组地址 G来标识一个组播组， 每个组播组可以有任意多个组 播源和接收者， 需要利用汇集点（RP, 全称为 Rendezvous Point )进行共享树 ( RPT , 全称为 Rendezvous Point Tree )的建立， 并且通过组播源注册机制建 立最短路径树 SPT (全称为 Shortest Path Tree ) ； SSM和 MLDv2/IGMPv3相 结合， 使用组播组地址 G和组播源地址 S来标识一个组播会话， 也称为一个 频道， 每个频道只能有一个指定源和任意多个接收者， 在 SSM模型中不需要 选择汇集点 RP和维护共享树（RPT ) , 不需要进行组播源注册， 从而在网络 内直接构建以组播源 S为根、以接收者为叶子的 SPT,省去了 ASM模型中先 建立共享树再从共享树向最短路径树切换的过程， 从而能够从一开始就沿最 短路径树转发数据。 和 ASM比较， SSM是一种简单有效的组播模型， 它可 以克服 ASM在访问控制、 地址分配、 源发现、 易于遭受 DoS攻击等方面的 缺陷， 因此 SSM模型具有更强的可扩展性， 可以提高网络性能， 在未来的 Internet中具备更加广泛的应用前景。
为了处理同一路由器在不同接口上收到来自不同对端的相同组播信息， 需要对组播报文的入接口进行逆向路径转发 RPF (全称为 Reverse Path Forwarding )检查， 以决定转发还是丟弃该报文。 在 SSM模型中， RPF检查 的过程是： 接收组播报文的路由器以组播源的 IP地址为目的地址查找单播路 由表， 对应表项中的出接口为 RPF接口， 路由器认为由该 RPF接口接收到 的组播报文所经历的路径是从组播源到本地的最短路径， 将 RPF接口与组 播报文实际到达的接口相比较， 如果两接口相一致， 那么就认为这个组播包 是从正确路径而来， RPF检查成功； 如果两接口不一致， 将该组播报文丟弃。 作为路径判断依据的单播路由信息可以来源于任何一种单播路由协议、 组播 静态路由或者 MBGP路由协议。
对于移动组播， IETF在 MULTIMOB工作组致力于研究基于 PMIPv6的 移动组播机制， 目前提出了一种基本解决方案， 下面结合附图介绍该方案的 实现过程， 如图 la, 组播接收者 MN和组播源 MN-S(MN-Source)位于同一个 ΡΜΙΡνό域 , 组播源 MN-S当前连接在移动接入网关 P-MAG上 , ΜΝ连接在 移动接入网关 MAG上， MN和 MN-S的拓朴锚点可以是同一个 LMA也可以 是不同的 LMA。 在 SSM模型下， MN通过 MLDv2报告报文向 MAG报告自 己需要接收来自组播源 MN-S、 发往组播组 G的组播数据。 MAG 收到 MLDv2 Report报文后 , 向组播源 MN-S逐跳发送频道订阅报文（由 MAG发 往 LMA的订阅报文需要进行隧道封装， 由 LMA发往 P-MAG的订阅报文也 需要进行隧道封装）， 沿途所有路由器都创建（HoA, G )组播路由项， HoA 代表组播源 MN-S的地址， G代表组播地址， 从而构建以组播源 MN-S为根， 以组播接收者 MN为叶子的 SPT路径，从组播源 MN-S所属的 P-MAG到 LMA 的路径是 PMIPv6隧道， 从 LMA到 MN所属 MAG的路径是 PMIPv6隧道， 随后组播源 MN-S发出的组播数据沿着已建好的 SPT到达 MN, 组播转发路 径如图 la的 100a所示。 当 MN-S切换到新的移动接入网关 N-MAG, 通过以 上过程建立新的 SPT路径， 如图 la的 101a所示 。 从组播源 MN-S所属的 N-MAG到 LMA的路径是 PMIPv6隧道，从 LMA到 MN所属的 MAG的路径 是 PMIPv6隧道。 以上解决方案， 由 MN-S发往 MN的组播报文必须先通过 MN-S的移动 接入网关 MAG和本地移动锚点 （LMA )之间的 PMIPv6隧道进行发送， 组 播才艮文到达 MN的移动锚点 LMA后，必须通过 LMA和 MN的移动接入网关 之间的 PMIPv6隧道进行发送， 所以图 la所示 SPT路径 100a和 101a都不是 最短的组播转发路径， 降低了组播路由的效率。 并且当组播源 MN-S发生切 换时， 由于组播接收者 MN不知道组播源的切换事件， 造成严重的丟包， 并 且组播源切换后需要重建整个组播转发树， )入较大的组播协议开销和网络 负载。 因此， 目前基于 PMIPv6所提出的移动组播解决方法不可避免的造成 了非最短 SPT路径以及组播切换丟包， 降低了路由效率和移动组播的性能。
发明内容
本发明实施方式提供一种在组播源切换场景下建立优化路径的方法及系 统， 解决现有方案中组播源切换场景下非最短 SPT路径造成的路由效率低的 问题。
为了解决上述技术问题， 本发明提供了在组播源切换场景下建立优化路 径的方法， 包括：
组播源（ MN-S )的目标移动接入网关（ MAG )从所述 MN-S的源 MAG 或本地移动锚点 （LMA )获知所述 MN-S的组播服务信息， 根据所述 MN-S 的组播服务信息与组播接收端 ( MN )所属的 MAG建立组播隧道， 所述目标 MAG将所述 MN-S 的组播 4艮文通过所述组播隧道发送至所述 MN所属的 MAG„
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 以 及所述 MN所属的 MAG的地址， 包括一个或多个 MAG的地址。
所述目标 MAG与所述 MN所属的 MAG建立组播隧道的步骤包括： 所述目标 MAG建立到所述 MN所属的 MAG的隧道接口后， 根据所述 组播服务信息中组播源的地址和组播组地址创建组播路由项， 并将到所述 MN所属的 MAG的隧道接口添加到所述组播路由项的出接口列表中。
所述目标 MAG与所述 MN所属的 MAG建立组播隧道的步骤包括： 所述目标 MAG向所述 MN所属的 MAG发送组播隧道建立消息 , 并在 此消息中携带所述 MN-S的地址和用于指示更新组播路由项入接口的入接口 更新标志； 以及
所述 MN所属的 MAG收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接口，根据所述 MN-S的地址查找和更新相应组播路由项， 并将此组播路由项的入接口设置为到所述 MN-S的目标 MAG的隧道接口。
所述目标 MAG将所述 MN-S的组播 ^艮文通发送至所述 MN所属的 MAG 的步骤包括：
所述目标 MAG收到所述 MN-S发送的组播 文后， 向所维护的组播路 由项的出接口列表中的所有组播隧道接口发送所述组播 文。
该方法还包括：
所述 MN所属的 MAG通过所述组播隧道收到组播 文后， 判断收到组 播报文的组播隧道接口是所维护的组播路由项中的入接口时， 向该组播路由 项的出接口列表中的所有出接口转发。
所述目标 MAG通过扩展的切换发起消息从所述源 MAG获知所述 MN-S 的组播服务信息， 包括：
所述 MN-S向源接入网上报所述 MN-S的标识以及目标接入网标识 , 所 述源接入网向所述源 MAG发送携带 MN-S的标识以及目标接入网标识的切 换指示信息，所述源 MAG根据所述目标接入网标识确定所述目标 MAG的地 址， 向所述目标 MAG发送扩展的切换发起消息， 在此扩展的切换发起消息 中携带所述 MN-S的组播服务信息。
所述目标 MAG通过扩展的切换确认消息从所述源 MAG获知所述 MN-S 的组播服务信息， 包括：
所述 MN-S 经由目标接入网与所述目标 MAG建立连接后， 所述目标 MAG向源 MAG发送切换发起消息， 源 MAG向目标 MAG返回扩展的切换 确认消息时， 在此扩展的切换确认消息中携带所述 MN-S的组播服务信息。
所述目标 MAG通过扩展的绑定确认消息从所述 LMA获知所述 MN-S的 组播服务信息， 包括： 所述 MN-S离开所述源 MAG后 , 所述源 MAG向所述 LMA发送扩展的 撤销注册绑定更新消息， 在此消息中携带所述 MN-S的组播服务信息， 所述 LMA保存所述 MN-S的组播服务信息； 以及
所述 MN-S切换到所述目标 MAG后， 所述目标 MAG向所述 LMA发送 绑定确认消息中携带所述 MN-S的组播服务信息。
所述目标 MAG通过扩展的绑定确认消息从所述 LMA获知所述 MN-S的 组播服务信息， 包括：
所述源 MAG创建组播路由项的同时， 将所述 MN-S的组播服务信息同 步到所述 LMA上； 以及
所述 MN-S切换到所述目标 MAG后， 所述目标 MAG向所述 LMA发送 扩展的绑定确认消息中携带所述 MN-S的组播服务信息。
该方法还包括： 所述 MN不再接收所述 MN-S的组播报文时， 所述 MN 所属的 MAG向所述 MN-S所属的 MAG发送声明退出以所述 MN-S的地址为 目标地址的剪枝消息， 并删除所述 MN-S对应的组播路由项， 拆除到所述 MN-S所属的 MAG的组播隧道； 以及
所述 MN-S所属的 MAG更新维护的组播路由项的出接口列表， 将接收 剪枝消息的隧道接口从所述出接口列表中删除，拆除到所述 MN所属的 MAG 的组播隧道， 并将所述 MN-S的组播服务信息同步到 LMA上。
本发明实施方式还提供一种在组播源切换场景下建立优化路径的系统， 包括组播源 （MN-S ) , MN-S 的目标移动接入网关 （MAG ) , MN-S 的源 MAG, 本地移动锚点 （LMA ) 以及组播接收端 （MN )所属的 MAG;
所述目标 MAG设置为： 从所述 MN-S的源 MAG或本地移动锚点（ LMA ) 获知所述 MN-S的组播服务信息，根据所述 MN-S的组播服务信息与所述 MN 所属的 MAG建立组播隧道， 并将所述 MN-S的组播 文通过所述组播隧道 发送至所述 MN所属的 MAG。
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 以 及所述 MN所属的 MAG的地址， 包括一个或多个 MAG的地址。 所述目标 MAG是设置为通过如下方式建立组播隧道：在建立到所述 MN 所属的 MAG的隧道接口后， 根据所述组播服务信息中组播源的地址和组播 组地址创建组播路由项， 并将到所述 MN所属的 MAG的隧道接口添加到所 述组播路由项的出接口列表中。
所述目标 MAG是设置为通过如下方式建立组播隧道： 向所述 MN所属 的 MAG发送组播隧道建立消息， 并在此消息中携带所述 MN-S的地址和用 于指示更新组播路由项入接口的入接口更新标志；
所述 MN所属的 MAG设置为通过如下方式与所述 MN-S 所属的目标 MAG建立组播隧道： 收到所述组播隧道建立消息后， 建立到所述目标 MAG 的双向隧道的接口， 根据所述 MN-S的地址查找和更新相应组播路由项， 将 此组播路由项的入接口设置为到所述 MN-S的目标 MAG的隧道接口。
所述目标 MAG是设置为通过如下方式将所述 MN-S的组播 ^艮文发送至 所述 MN所属的 MAG: 收到所述 MN-S发送的组播 文后， 向所维护的组播 路由项的出接口列表中的所有组播隧道接口发送所述组播报文。
所述 MN所属的 MAG还设置为： 通过所述组播隧道收到组播报文后， 判断收到组播报文的组播隧道接口是所维护的组播路由项中的入接口时， 向 该组播路由项的出接口列表中的所有出接口转发所述组播报文。
本发明实施方式还提供一种移动接入网关， 包括组播处理模块， 所述组播处理模块设置为： 在所属移动接入网关 （MAG )作为组播源
( MN-S )的目标 MAG时，从所述 MN-S的源 MAG或本地移动锚点（ LMA ) 获知所述 MN-S的组播服务信息， 根据所述 MN-S的组播服务信息与组播接 收端（MN )所属的 MAG建立组播隧道， 并将所述 MN-S的组播 ^艮文通过所 述组播隧道发送至所述 MN所属的 MAG。
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 以 及所述 MN所属的 MAG的地址， 包括一个或多个 MAG的地址。
所述组播处理模块是设置为通过如下方式建立组播隧道： 在建立所述目 标 MAG到所述 MN所属的 MAG的隧道接口后， 根据所述组播服务信息中 组播源的地址和组播组地址创建组播路由项， 将所述目标 MAG到所述 MN 所属的 MAG的隧道接口添加到所述组播路由项的出接口列表中。
所述组播处理模块是设置为通过如下方式与所述 MN所属的 MAG建立 组播隧道： 向所述 MN所属的 MAG发送组播隧道建立消息， 并在此消息中 携带所述 MN-S 的地址和用于指示更新组播路由项入接口的入接口更新标 志； 以及
所述组播处理模块还设置为： 在所属 MAG作为所述 MN所属的 MAG 时， 收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接 口， 根据所述 MN-S的地址查找和更新相应组播路由项， 将此组播路由项的 入接口设置为所述 MN所属的 MAG到所述 MN-S的目标 MAG的隧道接口。
所述组播处理模块是设置为通过如下方式将所述 MN-S的组播报文发送 至所述 MN所属的 MAG: 收到所述 MN-S发送的组播 文后， 向所维护的组 播路由项的出接口列表中的所有组播隧道接口发送所述组播报文。
所述组播处理模块还设置为： 在所属 MAG作为所述 MN所属的 MAG 时， 通过所述组播隧道收到组播报文后， 判断收到组播报文的组播隧道接口 是所维护的组播路由项中的入接口时， 向该组播路由项的出接口列表中的所 有出接口转发该组播报文。
本方案提供的建立 SPT路径的方法可以提高组播接收端切换过程中的路 由效率和移动组播的性能。 附图概述
图 l a为现有技术中在 PMIPv6域中进行组播切换的场景示意图； 图 lb为实施例中组播源在 PMIPv6域内发生切换的场景示意图； 图 2为具体实施例一的组播源切换时快速建立优化 SPT路径的方法流程 图；
图 3为具体实施例二的组播源切换时快速建立优化 SPT路径的方法流程 图； 图 4为具体实施例三的组播源切换时快速建立优化 SPT路径的方法流程 图；
图 5a为具体实施例四的组播源向 LMA注册组播服务信息的方法流程图； 图 5b为具体实施例四的组播源切换时快速建立优化 SPT路径的方法流 程图。 本发明的较佳实施方式
在组播源切换场景下建立优化路径的方法， 包括： 组播源（MN-S )的目 标移动接入网关 （ MAG )从所述 MN-S的源 MAG或本地移动锚点 （ LMA ) 获知所述 MN-S的组播服务信息， 根据所述 MN-S的组播服务信息与组播接 收端 （ MN )所属的 MAG建立组播隧道， 所述目标 MAG将所述 MN-S的组 播才艮文通过所述组播隧道发送至所述 MN所属的 MAG。
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 对 端 MAG地址即所述 MN所属的 MAG的地址，所述对端 MAG地址包含一个 或多个 MAG的地址。
如图 lb为组播源在 PMIPv6域内切换时的场景图， MN-S代表组播源， P-MAG是 MN-S切换前的移动接入网关， N-MAG是 MN-S切换后的移动接 入网关， MAG是组播接收者 MN的移动接入网关， 图中画出了一组移动接入 网关 MAG, 其下连接了一组组播接收者 MN。
MN-S切换前， MN通过 MLDv2报告报文向 MAG报告自己需要接收来 自组播源 MN-S、 发往组播组 G的组播数据。 MAG收到 MLDv2 Report 4艮文 后， 根据组播源地址 HoA向 LMA查询 P-MAG的地址信息， 建立 P-MAG和 MAG之间的隧道， MAG通过隧道向组播源 MN-S发送频道订阅报文， 沿途 的路由器都创建（HoA, G )组播路由项， HoA代表组播源 MN-S的地址， G 代表组播地址， 从而构建以组播源 MN-S为根， 以组播接收者 MN为叶子的 优化的 SPT路径， 如图 lb的 100b所示。
根据本方案， 当 MN-S发生切换时快速建立优化 SPT路径的方法流程， 优化后的 SPT路径如图 lb的 101b所示。 上述方法中 , 所述目标 MAG建立到所述 MN所属的 MAG的隧道接口 后， 根据所述组播服务信息中组播源地址和组播组地址创建组播路由项， 将 所述目标 MAG到所述 MN所属的 MAG的隧道接口添加到所述组播路由项 的出接口列表中。
所述目标 MAG向所述 MN所属的 MAG发送组播隧道建立消息， 并在 此消息中携带所述 MN-S的地址和用于指示更新组播路由项入接口的入接口 更新标志， 所述 MN所属的 MAG收到所述组播隧道建立消息后， 建立到所 述目标 MAG的双向隧道的接口， 根据所述 MN-S的地址查找和更新相应组 播路由项， 将此组播路由项的入接口设置为所述 MN所属的 MAG到所述 MN-S的目标 MAG的隧道接口。
所述目标 MAG收到所述 MN-S发送的组播 文后， 向所维护的组播路 由项的出接口列表中的所有组播隧道接口发送所述组播报文。
所述 MN所属的 MAG通过所述组播隧道收到组播 文后， 判断收到组 播报文的组播隧道接口是组播路由项中的入接口时， 向组播路由项的出接口 列表中的所有出接口转发。
下面通过多个实施例进行说明。
实施例一
本实施例一中， 所述目标 MAG通过扩展的切换发起消息从所述源 MAG 获知所述 MN-S的组播服务信息，包括：所述 MN-S向源接入网上报所述 MN-S 的标识以及目标接入网标识， 所述源接入网向所述源 MAG发送携带 MN-S 的标识以及目标接入网标识的切换指示信息， 所述源 MAG根据所述目标接 入网标识确定所述目标 MAG的地址，向所述目标 MAG发送扩展的切换发起 消息， 在此扩展的切换发起消息中携带所述 MN-S的组播服务信息。
如图 2, 实施例一的具体实现方法包括以下步骤：
步骤 200, MN-S通过优化 SPT路径向 MN发送组播艮文， 如步骤 200b 所示， 组播数据通过 P-MAG和 MAG之间的隧道进行发送。
步骤 201 , MN-S检测到自己需要进行 MAG切换， 于是将自己的 ID和 新的接入点标识 AP-ID ^艮告给前一个接入网络 P-AN (即 MN-S切换前的接入 网络)。
步骤 202, P-AN收到来自 MN-S的报告 ( report )消息后， 向源移动接入 网关 P-MAG (即 MN-S当前的连接的移动接入网关)发送切换指示消息， 消息 中同样携带组播源的 MN-ID和新的接入点标识 AP-ID。
步骤 203 , P-MAG根据切换指示消息中新的接入点标识 AP-ID获得新的 移动接入网关 N-MAG的地址信息，并向 N-MAG发出一个切换发起消息 HI, 本方案通过扩展 HI, 在消息中携带 MN-S的组播服务信息， 组播服务信息包 括多条记录， 每条记录包括（HoA、 G、 对端 MAG地址）， HoA代表组播源 的地址， G代表组播组地址， 对端 MAG地址代表组播接收者 MN的移动接 入网关的地址， 此处可能是一个或多个 MAG的地址。 为简单起见， 本实施 例以一个对端 MAG为例进行说明 （实际部署中可能存在多个对端 MAG ) 。
值得说明的是， 所述组播服务信息包含的内容不限于上述字段， 实际应 用中可以根据需要新增其他字段。
步骤 204, N-MAG向 P-MAG发送切换确认消息 HAck,作为对切换发起 消息 HI的确认。
本方案通过定义一对新的移动头消息即代理组播信道消息 PMT ( Proxy Multicast Tunnel )和代理组播信道响应消息 PMTR ( Proxy Multicast Tunnel Reply ) 作为建立组播隧道的消息， 也可以扩展 PBU/PBA ( Proxy Binding Update/Proxy Binding Acknowledgement ) 消息作为建立组播隧道的消息。
步骤 205 , N-MAG根据组播服务信息中的对端 MAG地址向 MAG发送
PMT消息请求与 MAG建立组播隧道， PMT消息中携带组播源的地址 HoA 以及用于指示更新组播路由项入接口的入接口更新标志， PMT消息中可以携 带两个新的移动选项： 组播源地址选项和入接口更新选项， 组播源地址选项 用来携带组播源的地址， 入接口更新选项用来通知对端 MAG更新组播路由 项的入接口。
步骤 206, MAG收到 PMT消息后， 向 N-MAG发送代理组播隧道建立 应答消息 PMTR, 并建立到 N-MAG的双向隧道的接口。
步骤 207 , MAG根据 PMT消息中的入接口更新选项和组播源地址选项 对组播路由项进行更新： MAG根据组播源地址查找本地组播路由项， 并将组 播路由项的入接口更新为 MAG到 N-MAG的隧道接口。
步骤 208, N-MAG收到 PMTR消息后，建立到 MAG的双向隧道的接口， 并根据组播服务信息中的组播源地址和组播组地址创建组播路由项， 将 N-MAG到 MAG的隧道接口添加到组播路由项的出接口列表中。
步骤 209, 通过以上步骤， N-MAG和 MAG之间的双向组播隧道建立完 成， 该双向隧道用于承载组播控制报文和组播数据报文。
步骤 210, MN-S与新的接入网路 N-AN建立连接。
步骤 211 , 新的接入网络 N-AN与新的移动接入网关 N-MAG建立连接。 步骤 212, MN-S向组播组 G发送组播 4艮文。
步骤 213 , N-MAG收到组播报文后， 查找组播路由项， 向出接口列表中 的所有接口发送组播报文。 由步骤 208可知， 出接口列表中保存了新的隧道 接口， N-MAG将组播报文进行隧道封装后发送给对端 MAG。
步骤 214, MAG对报文进行解封装后， 查找组播路由项， 向出接口列表 中的所有接口发送该组播报文， 最终 MN会收到该组播报文。 由步骤 207可 保证， MAG接收组播报文的接口与组播路由项中保存的入接口匹配， 直接向 所有出接口转发组播报文； 如果 MAG没有及时进行步骤 207的路由项更新， 则接收组播报文的接口 （与 N-MAG建立的隧道接口）与组播路由项中保存 的入接口 （与 P-MAG建立的隧道接口）不匹配， 则 MAG会对该组播 文进 行 RPF检查 , 如果 RPF检查得到的 RPF接口与接收组播报文的接口匹配， MAG更新组播路由项的入接口为接收组播报文的接口 （即新的隧道接口） ； 如果 RPF检查得到的 RPF接口与接收组播报文的接口不匹配，则丟弃这个来 自错误路径的报文。
本实施例结合 PFMIPv6协议的预先注册快速切换技术， 在 MN-S切换到 新的移动接入网关 N-MAG前， 预先建立好优化的 SPT路径， 路径所经过的 路由器都在其转发表中生成了相应的组播路由项， 运用本方法， 组播接收者 MN能够在 MN-S发生切换后通过优化 SPT路径快速获取组播数据， 从而提 高了组播服务质量和组播转发效率。 实施例二
本实施例二中， 所述目标 MAG通过扩展的切换确认消息从所述源 MAG 获知所述 MN-S的组播服务信息， 包括： 所述 MN-S经由目标接入网与所述 目标 MAG建立连接后， 所述目标 MAG向源 MAG发送切换发起消息， 源 MAG向目标 MAG返回扩展的切换确认消息时，在此扩展的切换确认消息中 携带所述 MN-S的组播服务信息。
如图 3 , 实施例二的具体实现方法包括：
步骤 300, MN-S通过优化 SPT路径向 MNs发送组播报文， 如步骤 300b 所示， 组播数据通过 P-MAG和 MAG之间的隧道进行发送。
步骤 301 , MN-S发生切换， MN-S与新的接入网路 N-AN建立连接。 步骤 302, 新的接入网络 N-AN与新的移动接入网关 N-MAG建立连接， N-MAG通过 P-AN的 AP-ID获得 P-MAG的地址信息。
步骤 303 , N-MAG向 P-MAG发出一个切换发起消息 ΗΙ。
步骤 304, P-MAG向 N-MAG发送切换确认消息 HAck,扩展 HAck消息， 在消息中携带 MN-S 的组播服务信息， 组播服务信息包含的内容与步骤 203 中描述的相同。
步骤 305〜步骤 309的处理流程与步骤 205〜步骤 209相同， 此处不再赘 述。
步骤 310〜步骤 312的处理流程与步骤 212〜步骤 214相同，此处不再赘述。 本实施例结合 PFMIPv6协议的过后注册快速切换技术， 在 MN-S切换到 新的移动接入网关 N-MAG的过程中 , N-MAG通过向 P-MAG请求组播服务 信息预先建立好优化的 SPT路径， 路径所经过的路由器都在其转发表中生成 了相应的组播路由项， 运用本方法， 组播接收者 MN能够在 MN-S发生切换 后通过优化 SPT路径快速获取组播数据， 从而提高了组播服务质量和组播转 发效率。 实施例三
本实施例三中，所述目标 MAG通过扩展的绑定确认消息从所述 LMA获 知所述 MN-S的组播服务信息， 包括： 所述 MN-S离开所述源 MAG后， 所 所述 MN-S的组播服务信息，所述 LMA保存所述 MN-S的组播服务信息； 所 述 MN-S切换到所述目标 MAG后， 所述目标 MAG向所述 LMA发送绑定更 认消息中携带所述 MN-S的组播服务信息。
如图 4, 实施例三的具体方法包括以下步骤：
步骤 400, MN-S通过优化 SPT路径向 MNs发送组播报文， 如步骤 400b 所示组播数据通过 P-MAG和 MAG之间的隧道进行发送。
步骤 401 , MN-S离开当前的移动接入网关 P-MAG, P-MAG向 LMA发 送生存时间 lifetime为零的 De-Registration绑定更新消息， 本发明通过扩展绑 定更新消息， 消息中携带 MN-S的组播服务信息， 组播服务信息包含的内容 与步骤 203中描述的相同。
步骤 402 , LMA收到来自 P-MAG的 De-Reg消息后， 将消息中携带的组 播服务信息保存到相应的绑定緩存表项 BCE中。
步骤 403 , LMA向 P-MAG发送绑定确认消息， 作为对 De-Reg消息的确 认。
步骤 404 , MN-S切换到新的移动接入网关 N-MAG , N-MAG向 LMA发 送绑定更新消息 PBU。
步骤 405, LMA更新本地绑定緩存表项 BCE, 通过对 PBA消息进行扩 展， LMA将 BCE中保存的组播服务信息携带在 PBA消息中发送给 N-MAG, 并删除本地 BCE中保存的组播服务信息。
步骤 406〜步骤 410的处理流程与步骤 205〜步骤 209相同， 此处不再赘 述。
步骤 411〜步骤 413 ,为后续组播报文转发流程，与实施例 1中的步骤 212~ 步骤 214相同， 此处不再赘述。 本实施例通过扩展绑定更新消息， 在组播源切换到新的移动接入网关
N-MAG时， 快速建立起优化的 SPT路径， 路径所经过的路由器都在其转发 表中生成了相应的组播路由项， 运用本方法， 组播接收者 MN能够在组播源 发生切换后通过优化 SPT路径快速获取组播数据， 从而提高了组播服务质量 和组播转发效率。
实施例四
本实施例四中，所述目标 MAG通过扩展的绑定确认消息从所述 LMA获 知所述 MN-S的组播服务信息， 具体包括： 所述源 MAG创建组播路由项的 同时，将所述 MN-S的组播服务信息同步到所述 LMA上； 所述 MN-S切换到 所述目标 MAG后，所述目标 MAG向所述 LMA发送绑定更新消息，所述 LMA 向所述目标 MAG返回扩展的绑定确认消息， 在此扩展的绑定确认消息中携 带所述 MN-S的组播服务信息。
如图 5a和图 5b, 为实施例四提供的当 MN发生切换时， 快速建立优化 SPT路径的一种方法流程图。
如图 5a 为组播源向 LMA 注册组播服务信息的流程， MAG-R(MAG-Receiver)为 组播接收者的移动接入网 关 ， MAG-S ( MAG-Source )为组播源的移动接入网关， 注册流程包括以下步骤：
步骤 500 , MAG-R通过组播隧道向 MAG-S发送 PIM Join消息。
步骤 501 , MAG-S根据 PIM Join消息中携带的频道信息创建组播路由项， 并将接收 PIM Join消息的隧道接口添加到出接口列表中。 如果 MAG-S上已 经存在该频道的组播路由项， 则直接更新出接口列表， 即将接收 PIM Join消 息的隧道接口添加到出接口列表中。
步骤 502, MAG-S将组播源的组播服务信息同步到组播源的 LMA上， 同步消息可以通过扩展 PBU消息来实现， 也可以定义新的移动头消息， 消息 中携带组播服务信息， 组播服务信息包含的内容与步骤 203中描述的内容相 同。
步骤 503 , LMA为组播源保存组播服务信息， 组播服务信息可以保存在 组播源对应的 BCE中 , 也可以单独保存。
步骤 504 ,如果 MAG-R下面的组播接收者 MN不再接收来自组播源 MN-S 的组播数据，则通过组播隧道向 MN-S的移动接入网关 MAG-S发送 PIM Prune 剪枝消息， 并拆除与 MAG-S之间的隧道。
步骤 505, MAG-S收到剪枝消息后， 更新相应的组播路由项， 将接收剪 枝消息的隧道接口从出接口列表中删除； 并拆除与 MAG-R之间的隧道。
步骤 506, MAG-S将组播源的组播服务信息同步到组播源的 LMA上， 同步消息可以通过扩展 PBU消息来实现， 也可以定义新的移动头消息， 消息 中携带组播服务信息， 组播服务信息包含的内容与步骤 203中描述的内容相 同。
步骤 507, LMA更新本地保存的 MN-S的组播服务信息， 从组播服务信 息中删除相应的记录（即删除发送剪枝消息的对端 MAG的相关记录） 。
通过以上步骤， LMA上保存了组播源的组播服务信息， 并能根据 SPT 路径的变化实时更新组播源的组播服务信息。
图 5b结合图 5a中保存的信息快速建立优化的 SPT路径，包括以下步骤： 步骤 500, MN-S通过优化 SPT路径向 MNs发送组播报文， 如步骤 500b 所示组播数据通过 P-MAG和 MAG之间的隧道进行发送。
步骤 501 , MN-S从当前的移动接入网关 P-MAG切换到新的移动接入网 关 N-MAG, N-MAG向 LMA发送绑定更新消息 PBU。
步骤 502 , LMA收到来自 P-MAG的 PBU消息后， 对相应的绑定緩存条 目 BCE进行更新， 并将该 BCE中保存的组播服务信息携带在 PBA消息中发 送给 N-MAG。
步骤 503〜步骤 507的处理流程与步骤 205〜步骤 209相同， 此处不再赘 述。
步骤 508〜步骤 510,为后续组播 文转发流程，与实施例 1中的步骤 212~ 步骤 214相同， 此处不再赘述。
本实施例通过 LMA对域内组播源的服务信息进行统一管理 ,当组播源切 换到新的移动接入网关 N-MAG时 , 由 N-MAG从 LMA快速获取组播源的组 播服务信息， 然后快速建立起优化的 SPT路径， 路径所经过的路由器都在其 转发表中生成了相应的组播路由项， 运用本方法， 组播接收者 MN能够在组 播源发生切换后通过优化 SPT路径快速获取组播数据， 从而提高了组播服务 质量和组播转发效率。
本发明实施例针对 ΡΜΙΡνό的场景， 并且运用 MLDv2进行 IPv6组播组 成员管理。 本发明中的技术方案同样适用于代理移动 IPv4的场景， 本领域的 技术人员可以根据本发明实施例中的技术方案， 并结合本领域的现有技术方 案即可实现。 在代理移动 IPv6中的移动节点使用 MLDv2加入组播组， 而在 代理移动 IPv4中的移动节点使用 IGMPv3加入组播组。
与上述方法相对应的在组播接收端切换场景下建立优化路径的系统包括 组播源 （ MN-S ) , MN-S的目标移动接入网关（ MAG ) , MN-S的源 MAG, 本地移动锚点 （LMA ) 以及 MN所属的 MAG。
所述目标 MAG设置为：从所述 MN-S的源 MAG或本地移动锚点（ LMA ) 获知所述 MN-S的组播服务信息， 根据所述 MN-S的组播服务信息与组播接 收端（ MN )所属的 MAG建立组播隧道， 将所述 MN-S的组播 4艮文通过所述 组播隧道发送至所述 MN所属的 MAG。
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 对 端 MAG地址即所述 MN所属的 MAG的地址，所述对端 MAG地址包含一个 或多个 MAG的地址。
所述目标 MAG是设置为通过如下方式建立组播隧道：在建立到所述 MN 所属的 MAG的隧道接口后， 根据所述组播服务信息中组播源地址和组播组 地址创建组播路由项， 将到所述 MN所属的 MAG的隧道接口添加到所述组 播路由项的出接口列表中。
所述目标 MAG是设置为通过如下方式建立组播隧道： 向所述 MN所属 的 MAG发送组播隧道建立消息， 并在此消息中携带所述 MN-S的地址和用 于指示更新组播路由项入接口的入接口更新标志；
所述 MN所属的 MAG收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接口，根据所述 MN-S的地址查找和更新相应组播路由项， 将此组播路由项的入接口设置为到所述 MN-S的目标 MAG的隧道接口。 所述目标 MAG是设置为收到所述 MN-S发送的组播报文后， 向所维护 的组播路由项的出接口列表中的所有组播隧道接口发送所述组播报文。
所述 MN所属的 MAG通过所述组播隧道收到组播 文后， 判断收到组 播报文的组播隧道接口是组播路由项中的入接口时， 向组播路由项的出接口 列表中的所有出接口转发。
述。
本方案中的移动接入网关包括组播处理模块。所述组播处理模块设置为： 在所属移动接入网关（ MAG )作为组播源（ MN-S )的目标 MAG时， 从所述 MN-S的源 MAG或本地移动锚点 （ LMA )获知所述 MN-S的组播服务信息， 根据所述 MN-S的组播服务信息与组播接收端（MN )所属的 MAG建立组播 隧道， 将所述 MN-S 的组播报文通过所述组播隧道发送至所述 MN所属的 MAG„
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 对 端 MAG地址即所述 MN所属的 MAG的地址，所述对端 MAG地址包含一个 或多个 MAG的地址。
所述组播处理模块是设置为通过如下方式建立组播隧道： 在建立到所述 MN所属的 MAG的隧道接口后，根据所述组播服务信息中组播源地址和组播 组地址创建组播路由项， 将所述目标 MAG到所述 MN所属的 MAG的隧道 接口添加到所述组播路由项的出接口列表中。 所述组播处理模块还设置为通过如下方式建立组播隧道： 在所属 MAG 作为所述 MN-S的目标 MAG时， 向所述 MN所属的 MAG发送组播隧道建 立消息， 并在此消息中携带所述 MN-S的地址和用于指示更新组播路由项入 接口的入接口更新标志； 以及， 在所属 MAG作为所述 MN所属的 MAG时， 收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接口， 根据所述 MN-S的地址查找和更新相应组播路由项， 将此组播路由项的入接 口设置为所述 MN所属的 MAG到所述 MN-S的目标 MAG的隧道接口。 所述组播处理模块是设置为通过如下方式将所述 MN-S的组播报文发送 至所述 MN所属 的 MAG: 在所属 MAG作为所述 MN-S的目标 MAG时， 收到所述 MN-S发送的组播报文后， 向所维护的组播路由项的出接口列表中 的所有组播隧道接口发送所述组播 文。
所述组播处理模块还设置为： 在所属 MAG作为所述 MN所属的 MAG 时， 通过所述组播隧道收到组播报文后， 判断收到组播报文的组播隧道接口 是组播路由项中的入接口时， 向组播路由项的出接口列表中的所有出接口转 发。
组播处理模块的执行方式与上述方法中相应相同， 此处不再重复描述。
需要说明的是， 在不冲突的情况下， 本申请中的实施例及实施例中的特 征可以相互任意组合。 当然， 本发明还可有其他多种实施例， 在不背离本发明精神及其实质的 但这些相应的改变和变形都应属于本发明所附的权利要求的保护范围。
本领域普通技术人员可以理解上述方法中的全部或部分步骤可通过程序 来指令相关硬件完成， 所述程序可以存储于计算机可读存储介质中， 如只读 存储器、 磁盘或光盘等。 可选地， 上述实施例的全部或部分步骤也可以使用 一个或多个集成电路来实现。 相应地， 上述实施例中的各模块 /单元可以釆用 硬件的形式实现， 也可以釆用软件功能模块的形式实现。 本发明不限制于任 何特定形式的硬件和软件的结合。
工业实用性 本发明实施方式提供的建立 SPT路径的方法和系统可以提高组播接收 端切换过程中的路由效率和移动组播的性能。

Claims

权 利 要 求 书
1、 一种在组播源切换场景下建立优化路径的方法， 包括：
组播源（ MN-S )的目标移动接入网关（ MAG )从所述 MN-S的源 MAG 或本地移动锚点 （LMA )获知所述 MN-S的组播服务信息， 根据所述 MN-S 的组播服务信息与组播接收端 ( MN )所属的 MAG建立组播隧道， 所述目标 MAG将所述 MN-S 的组播 ^艮文通过所述组播隧道发送至所述 MN所属的 MAG„
2、 如权利要求 1所述的方法， 其中，
所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 以 及所述 MN所属的 MAG的地址， 包括一个或多个 MAG的地址。
3、 如权利要求 1所述的方法， 其中， 所述目标 MAG与所述 MN所属的 MAG建立组播隧道的步骤包括：
所述目标 MAG建立到所述 MN所属的 MAG的隧道接口后， 根据所述 组播服务信息中组播源的地址和组播组地址创建组播路由项， 并将到所述 MN所属的 MAG的隧道接口添加到所述组播路由项的出接口列表中。
4、 如权利要求 1所述的方法， 其中， 所述目标 MAG与所述 MN所属的 MAG建立组播隧道的步骤包括：
所述目标 MAG向所述 MN所属的 MAG发送组播隧道建立消息， 并在 此消息中携带所述 MN-S的地址和用于指示更新组播路由项入接口的入接口 更新标志； 以及
所述 MN所属的 MAG收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接口，根据所述 MN-S的地址查找和更新相应组播路由项， 并将此组播路由项的入接口设置为到所述 MN-S的目标 MAG的隧道接口。
5、 如权利要求 1或 3所述的方法， 其中， 所述目标 MAG将所述 MN-S 的组播报文通发送至所述 MN所属的 MAG的步骤包括：
所述目标 MAG收到所述 MN-S发送的组播 文后， 向所维护的组播路 由项的出接口列表中的所有组播隧道接口发送所述组播报文。
6、 如权利要求 1或 4所述的方法， 还包括：
所述 MN所属的 MAG通过所述组播隧道收到组播 文后， 判断收到组 播报文的组播隧道接口是所维护的组播路由项中的入接口时， 向该组播路由 项的出接口列表中的所有出接口转发。
7、 如权利要求 1所述的方法， 其中， 所述目标 MAG通过扩展的切换发 起消息从所述源 MAG获知所述 MN-S的组播服务信息， 包括：
所述 MN-S向源接入网上报所述 MN-S的标识以及目标接入网标识 , 所 述源接入网向所述源 MAG发送携带 MN-S的标识以及目标接入网标识的切 换指示信息，所述源 MAG根据所述目标接入网标识确定所述目标 MAG的地 址， 向所述目标 MAG发送扩展的切换发起消息， 在此扩展的切换发起消息 中携带所述 MN-S的组播服务信息。
8、 如权利要求 1所述的方法， 其中， 所述目标 MAG通过扩展的切换确 认消息从所述源 MAG获知所述 MN-S的组播服务信息， 包括：
所述 MN-S 经由目标接入网与所述目标 MAG建立连接后， 所述目标 MAG向源 MAG发送切换发起消息， 源 MAG向目标 MAG返回扩展的切换 确认消息时， 在此扩展的切换确认消息中携带所述 MN-S的组播服务信息。
9、 如权利要求 1所述的方法， 其中， 所述目标 MAG通过扩展的绑定确 认消息从所述 LMA获知所述 MN-S的组播服务信息， 包括：
所述 MN-S离开所述源 MAG后， 所述源 MAG向所述 LMA发送扩展的 撤销注册绑定更新消息， 在此消息中携带所述 MN-S的组播服务信息， 所述 LMA保存所述 MN-S的组播服务信息； 以及
所述 MN-S切换到所述目标 MAG后， 所述目标 MAG向所述 LMA发送 绑定确认消息中携带所述 MN-S的组播服务信息。
10、 如权利要求 1所述的方法， 其中， 所述目标 MAG通过扩展的绑定 确认消息从所述 LMA获知所述 MN-S的组播服务信息， 包括：
所述源 MAG创建组播路由项的同时， 将所述 MN-S的组播服务信息同 步到所述 LMA上； 以及 所述 MN-S切换到所述目标 MAG后， 所述目标 MAG向所述 LMA发送 扩展的绑定确认消息中携带所述 MN-S的组播服务信息。
11、 如权利要求 10所述的方法， 还包括：
所述 MN不再接收所述 MN-S的组播艮文时， 所述 MN所属的 MAG向 所述 MN-S所属的 MAG发送声明退出以所述 MN-S的地址为目标地址的剪 枝消息，并删除所述 MN-S对应的组播路由项，拆除到所述 MN-S所属的 MAG 的组播隧道； 以及
所述 MN-S所属的 MAG更新维护的组播路由项的出接口列表， 将接收 剪枝消息的隧道接口从所述出接口列表中删除，拆除到所述 MN所属的 MAG 的组播隧道， 并将所述 MN-S的组播服务信息同步到 LMA上。
12、一种在组播源切换场景下建立优化路径的系统，包括组播源（MN-S ), MN-S的目标移动接入网关（ MAG ) , MN-S的源 MAG,本地移动锚点（ LMA ) 以及组播接收端 （MN )所属的 MAG;
所述目标 MAG设置为：从所述 MN-S的源 MAG或本地移动锚点（ LMA ) 获知所述 MN-S的组播服务信息，根据所述 MN-S的组播服务信息与所述 MN 所属的 MAG建立组播隧道， 并将所述 MN-S的组播 文通过所述组播隧道 发送至所述 MN所属的 MAG。
13、如权利要求 12所述的系统，其中，所述 MN-S的组播服务信息包括： 所述 MN-S的地址， 组播组地址， 以及所述 MN所属的 MAG的地址， 包括 一个或多个 MAG的地址。
14、 如权利要求 12所述的系统， 其中， 所述目标 MAG是设置为通过如 下方式建立组播隧道：
在建立到所述 MN所属的 MAG的隧道接口后， 根据所述组播服务信息 中组播源的地址和组播组地址创建组播路由项 ,并将到所述 MN所属的 MAG 的隧道接口添加到所述组播路由项的出接口列表中。
15、 如权利要求 12所述的系统， 其中， 所述目标 MAG是设置为通过如 下方式建立组播隧道： 向所述 MN所属的 MAG发送组播隧道建立消息， 并 在此消息中携带所述 MN-S的地址和用于指示更新组播路由项入接口的入接 口更新标志；
所述 MN所属的 MAG设置为通过如下方式与所述 MN-S 所属的目标 MAG建立组播隧道： 收到所述组播隧道建立消息后， 建立到所述目标 MAG 的双向隧道的接口， 根据所述 MN-S的地址查找和更新相应组播路由项， 将 此组播路由项的入接口设置为到所述 MN-S的目标 MAG的隧道接口。
16、 如权利要求 12或 14所述的系统， 其中， 所述目标 MAG是设置为 通过如下方式将所述 MN-S的组播 文发送至所述 MN所属的 MAG:
收到所述 MN-S发送的组播报文后， 向所维护的组播路由项的出接口列 表中的所有组播隧道接口发送所述组播报文。
17、 如权利要求 12或 15所述的系统， 其中， 所述 MN所属的 MAG还 设置为： 通过所述组播隧道收到组播报文后， 判断收到组播报文的组播隧道 接口是所维护的组播路由项中的入接口时， 向该组播路由项的出接口列表中 的所有出接口转发所述组播报文。
18、 一种移动接入网关， 包括组播处理模块， 所述组播处理模块设置为： 在所属移动接入网关（ MAG )作为组播源（ MN-S )的目标 MAG时， 从所述 MN-S的源 MAG或本地移动锚点 （ LMA )获知所述 MN-S的组播服务信息， 根据所述 MN-S的组播服务信息与组播接收端（MN )所属的 MAG建立组播 隧道， 并将所述 MN-S的组播 ^艮文通过所述组播隧道发送至所述 MN所属的 MAG„
19、 如权利要求 18所述的移动接入网关， 其中， 所述 MN-S的组播服务 信息包括：
所述 MN-S的地址， 组播组地址， 以及所述 MN所属的 MAG的地址， 包括一个或多个 MAG的地址。
20、 如权利要求 18所述的移动接入网关， 其中， 所述组播处理模块是设 置为通过如下方式建立组播隧道：
在建立所述目标 MAG到所述 MN所属的 MAG的隧道接口后， 根据所 述组播服务信息中组播源的地址和组播组地址创建组播路由项， 将所述目标 MAG到所述 MN所属的 MAG的隧道接口添加到所述组播路由项的出接口列 表中。
21、 如权利要求 18所述的移动接入网关， 其中， 所述组播处理模块是设 置为通过如下方式与所述 MN所属的 MAG建立组播隧道：
向所述 MN所属的 MAG发送组播隧道建立消息， 并在此消息中携带所 述 MN-S的地址和用于指示更新组播路由项入接口的入接口更新标志； 以及 所述组播处理模块还设置为： 在所属 MAG作为所述 MN所属的 MAG 时， 收到所述组播隧道建立消息后， 建立到所述目标 MAG的双向隧道的接 口， 根据所述 MN-S的地址查找和更新相应组播路由项， 将此组播路由项的 入接口设置为所述 MN所属的 MAG到所述 MN-S的目标 MAG的隧道接口。
22、 如权利要求 18或 20所述的移动接入网关， 其中， 所述组播处理模 块是设置为通过如下方式将所述 MN-S 的组播报文发送至所述 MN所属的 MAG:
收到所述 MN-S发送的组播报文后， 向所维护的组播路由项的出接口列 表中的所有组播隧道接口发送所述组播报文。
23、 如权利要求 18或 21所述的移动接入网关， 其中， 所述组播处理模 块还设置为：
在所属 MAG作为所述 MN所属的 MAG时， 通过所述组播隧道收到组 播报文后， 判断收到组播报文的组播隧道接口是所维护的组播路由项中的入 接口时， 向该组播路由项的出接口列表中的所有出接口转发该组播报文。
PCT/CN2012/082854 2011-10-19 2012-10-12 在组播源切换场景下建立优化路径的方法及系统 WO2013056633A1 (zh)

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CN101136847A (zh) * 2006-08-31 2008-03-05 华为技术有限公司 一种本地移动性管理网络的报文路由方法和系统
CN101465887A (zh) * 2007-12-20 2009-06-24 华为技术有限公司 移动接入网关地址获取方法、系统及装置
CN101940014A (zh) * 2008-02-04 2011-01-05 爱立信电话股份有限公司 用于提供路由优化的方法和设备

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CN101179457B (zh) * 2006-11-09 2010-10-27 华为技术有限公司 一种基于本地移动管理域中路由优化的切换方法
JP4478700B2 (ja) * 2007-05-28 2010-06-09 シャープ株式会社 ネットワークベースｉｐモビリティプロトコルを利用した通信システム、制御装置、ルータ及びその通信方法
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