CN106992935B

CN106992935B - The method and apparatus of operator's multicast tree is established in DAM system

Info

Publication number: CN106992935B
Application number: CN201610038177.XA
Authority: CN
Inventors: 张立新
Original assignee: Nokia Shanghai Bell Co Ltd
Current assignee: Nokia Shanghai Bell Co Ltd
Priority date: 2016-01-20
Filing date: 2016-01-20
Publication date: 2019-09-24
Anticipated expiration: 2036-01-20
Also published as: CN106992935A

Abstract

Embodiment of the disclosure provides a kind of method and apparatus that operator's multicast tree is established in DAM system, the described method includes: at least one of Border Gateway Protocol (BGP) message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI is transmitted between the network unit in the DAM system, to establish operator's multicast tree；Wherein the BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message include following attribute: MP_REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulate extended community attribute.

Description

The method and apparatus of operator's multicast tree is established in DAM system

Technical field

Embodiment of the disclosure is related to distributed couple in multiplexer.More specifically, embodiment of the disclosure is related to distribution The method for building up and equipment comprising formula or selecting type operator multicast tree in access multiplexer system.

Background technique

Embodiment of the disclosure technical problem to be solved is derived from distributed couple in multiplexer (DAM) model.It is discussing Before specific technical problem, some background techniques of DAM are first introduced.

In summary, DAM is a kind of access device, by the distributed module structure for having interconnected any type of " virtual link " At." virtual link " refers to layer 2 (L2) the superposition tunnel established on layer 3 (L3) bottom-layer network.L2 superposition tunnel can be point-to-point Tunnel and point-to-multipoint tunnel.Fig. 1 shows the logical model of DAM.

Fig. 1 shows the deployment model of distributed DAM, wherein mainly including 4 generic modules: edge router module (ERM mould Block), it runs internetwork-ing/multiprotocol label switching (IP/MPLS) data plane functions；It controls planar module (CPM module), It runs control plane and management plane function；Service plane module (SPM), it runs business and application function；It remotely accesses Module (RAM module), which is located at close to the position of user, and terminates various specific access layer technologies, for example, described Various specific access layer technologies are: based on DOCSIS (data over cable service interface specification) cable access technology, with The too soft exchange technology of passive optical network (EPON) and Gigabit-capable Passive Optical Network (GPON) or various types of numbers is used Unified Ethernet interface is presented to network side for family line xDSL access technology, RAM module.

All center modules (ERM, CPM and SPM) constitute mesh topology between each other in Fig. 1, i.e., they are between any two It can directly transmit and received data packet, they constitute the center of distribution DAM as a whole.And all RAM moulds Block constitutes the spoke of DAM system, i.e., each RAM module is only capable of directly transmitting between center module and received data packet, RAM mould Block cannot directly transmit between any two and received data packet.Moreover, by bottom transmission network (generally Ethernet or IP Net) on construct a stacking network, all modules of DAM system can be mutually unified into an entirety, part of module shown in FIG. 1 can Virtually to turn to the software run on standard server or data center's virtual machine.

Presently, there are many kinds of stacking networks, for example, operator backbone bridges network (also referred to as in medium access control (MAC) in encapsulation MAC network), 2 Virtual Private Network of layer (L2VPN) or 3 Virtual Private Network of layer (L3VPN) based on MPLS.For Acquisition better expandability, embodiment of the disclosure assume bottom-layer network be Pure IP network (that is, be not related to Ethernet and MPLS bottom-layer network).Because in terms of embodiment of the disclosure is only focusing only on DAM, simultaneously it is also assumed that stacking network mentions L2 service is supplied, specifically, it is assumed that it is 802.3 ethernet frame of IEEE (that is, the disclosure that L2, which is superimposed the payload in tunnel, Embodiment is not related to L3 stacking network).7365 He of RFC of network virtualization (IETF NVO3) working group on IETF layer 3 The documents such as draft-ietf-nvo3-arch provide general for describing L2 and L3 stacking network on L3 bottom-layer network Infrastructure component and term, therefore, embodiment of the disclosure refer to infrastructure component and the term of IETF NVO3 in large quantities to describe DAM model.

Although embodiment of the disclosure refers to the infrastructure component and term of IETF NVO3 in large quantities, it should be noted that , there are significant differences between the application scenarios of embodiment of the disclosure and the application scenarios of IETF NVO3.IETF NVO3 framework for data center network virtualization and design, the enormous amount of L2 stacking network therein and be in nature State.But in DAM model, the quantity of L2 stacking network is very limited and is relative quiescent in nature.In DAM model The property of L2 stacking network is very similar to IETF L2VPN, but IETF L2VPN be only supported in MPLS encapsulate MPLS or The L2 of encapsulation MPLS is superimposed tunnel in generic route encapsulation (GRE), without being based on IP and compatibility required for supporting in DAM model The L2 of NVO3 is superimposed tunnel.Therefore, the target of embodiment of the disclosure can be counted as expanding IETF L2VPN technology Exhibition is to support NVO3 L2 to be superimposed tunnel.

It should be noted that in embodiment of the disclosure, NVO3 L2 superposition tunnel refers to building on IP bottom-layer network Vertical can be superimposed tunnel by any L2 that IETF NVO3 framework is supported.Current most widely used IETF NVO3 L2 is folded Tunnel type in screening network is virtual expansible local area network (VXLAN) in RFC 7348, draft-sridharan- The network virtualization (NVGER) and RFC 4023 using generic route encapsulation in virtualization-nvgre document In MPLS is encapsulated in GRE, and the default tunnel-like that will be will use in DAM model is also contained in these tunnel types Type.

In DAM model shown in Fig. 1, an important technical problem is to establish operator's multicast tree effectively to transmit Multicast (and broadcast) flow from central node to spoke nodes (for example, from ERM module to RAM module).Flux of multicast includes Basic flux of multicast and/or User IP multicast (user multicast) flow.In embodiment of the disclosure, basic flux of multicast refers to It is broadcast, unknown and multicast (BUM) ether caused by the agreements such as address resolution protocol (ARP), network discovery (ND) The flow of frame.

In short, embodiment of the disclosure attempts the Virtual Private LAN Service (VPLS) to defined in RFC 7117 Multicast mechanism be extended, to be applied to DAM model, with carry out virtual network (VN) example find automatically and comprising Formula/selecting type operator multicast tree foundation, so as to more effectively transmit BUM flow and/or user multicast flow.

Currently, other than some general discussion in draft-ietf-nvo3-mcast-framework document, also The not multicasting solution for the formal standard of IETF NOV3 network.It might be that NVO3 multicasting solution It will be based on central server.However, since the L2 stacking network used in DAM model will be similar to traditional L2VPN, So embodiment of the disclosure designs the solution of DAM multicast based on being extended to the VPLS multicasting solution in RFC 7117 Scheme.

At this stage, RFC 7117 is the standard solution for the transport multicast flow in VPLS network.However not Good fortune, RFC 7117 only supports the Multicast Tunnel based on MPLS, such as passes through Resource Reservation Protocol-traffic engineering (RSVP- TE point-to-multipoint (P2MP) label switched path (LSP)) established, or (mLDP) is extended by the multiple spot of tag distribution protocol The P2MP LSP established, and be that can not establish these multicasts in the pure IP bottom-layer network for the deployment DAM that we are assumed Tunnel.

It can be with reference to a kind of entitled " distribution couple in multiplexer DAM stacking network system and its dress of same inventor Set " first application for a patent for invention obtain other relevant technology contents.

Summary of the invention

According to one aspect of the disclosure, the method that operator's multicast tree is established in DAM system is provided, comprising: Border Gateway Protocol (BGP) message BGP-VNAD-IPMSI or BGP-VNAD- is transmitted between network unit in the DAM system At least one of SPMSI, to establish operator's multicast tree；The wherein BGP-VNAD-IPMSI message and described BGP-VNAD-SPMSI message includes following attribute: MP_REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulation Extended community attribute.It should be noted that the BGP in embodiment of the disclosure refers to multi-protocols extending boundary gateway protocol (MP-BGP)。

Optionally, by the MP_REACH_NLRI attribute, to issue up to the purpose network information and corresponding next-hop Information, and transmit the virtual network context identifier ID under VN example；Operation is carried by the PMSI_TUNNEL attribute Quotient's multicast services interface (PMSI) tunnel information；And extended community attribute is encapsulated to indicate stacking network tunnel by the BGP The tunnel type of road encapsulation.

Optionally, when transmitting the BGP-VNAD-IPMSI message between the network unit, by VN context ID word Section is included in the MP_REACH_NLRI attribute, to distinguish different VN contexts.

Optionally, pass through attribute field included in the PMSI_TUNNEL attribute, tunnel type field, VN or more The tunnel identifier field of literary id field and variable-length, to carry the PMSI tunnel information.

Optionally, the tunnel type field is arranged to the Protocol Independent Multicast (PIM- for supporting to establish designated multicast source SSM multicast tree).

Optionally, the tunnel type field is arranged to the Protocol Independent Multicast (PIM-SM) for supporting to establish sparse mode Multicast tree.

Optionally, the BGP encapsulation extended community attribute is arranged to support virtual expansible local area network.

Optionally, the BGP encapsulation extended community attribute is arranged to the network virtual for supporting to use generic route encapsulation Change.

Optionally, the BGP encapsulation extended community attribute is arranged to support to encapsulate multi-protocols in generic route encapsulation Tag switching.

Other side according to an embodiment of the present disclosure, the BGP-VNAD-IPMSI message and the BGP-VNAD- SPMSI message also includes L2VPN identifier extension group attribute and route target extended community attribute.

Optionally, the specific virtual net in the DAM system is identified by the L2VPN identifier extension group attribute Network example；And the topological structure in stacking network tunnel is controlled by the route target extended community attribute.

Equipment in a kind of DAM system another aspect of the present disclosure provides, comprising: to transmit BGP message At least one of BGP-VNAD-IPMSI or BGP-VNAD-SPMSI, the processing unit to establish operator's multicast tree；Wherein The BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message include following attribute: MP_REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulate extended community attribute.

Optionally, the processing unit is by the MP_REACH_NLRI attribute, issuing up to the purpose network information and Corresponding next hop information, and transmit the virtual network context identifier ID under VN example；Belonged to by the PMSI_TUNNEL Property carries PMSI tunnel information；And extended community attribute is encapsulated to indicate stacking network tunnel encapsulation by the BGP Tunnel type.

Optionally, when the processing unit transmits the BGP-VNAD-IPMSI message between the network unit, VN context ID field is included in the MP_REACH_NLRI attribute, to distinguish different VN contexts.

Optionally, the tunnel type field is arranged to support to establish the multicast of the Protocol Independent Multicast in designated multicast source Tree.

Optionally, the tunnel type field is arranged to support to establish the multicast of the Protocol Independent Multicast of sparse mode Tree.

Other side according to an embodiment of the present disclosure, the BGP-VNAD-IPMSI that the processing unit is transmitted Message and the BGP-VNAD-SPMSI message also include L2VPN identifier extension group attribute and route target extended community category Property.

Optionally, the processing unit is identified by the L2VPN identifier extension group attribute in the DAM system Specific virtual network example；And the topology in stacking network tunnel is controlled by the route target extended community attribute Structure.

As described above, embodiment of the disclosure extends multicasting solution specified in RFC 7117, make it It can be applied to pure IP bottom-layer network.Moreover, this extension proposed in embodiment of the disclosure retains as much as possible The existing mechanism and process that can be reused in RFC 7117.

Detailed description of the invention

Fig. 1 shows DAM model；

Fig. 2 shows include formula operator multicast tree between DAM module；

Fig. 3 shows the BGP signaling comprising formula operator multicast tree for DAM；

Fig. 4 shows the BGP signaling of the selecting type operator multicast tree for DAM；

Fig. 5 shows the coded format of PMSI_TUNNEL (tunnel PMSI_) attribute；And

Fig. 6 shows the equipment in DAM system according to an embodiment of the present disclosure.

Specific embodiment

In the specific descriptions of following optional embodiment, reference is constituted to the attached drawing of a part of this disclosure.It is each attached The specific embodiment that can be realized the disclosure has been illustrated by way of example in figure.However, it is desirable to be appreciated that, example embodiment It is not intended to exhaustive all embodiments according to the disclosure.

Following embodiment is illustrated distributed couple in multiplexer using the framework and term of IETF NVO3, and It is illustrated by taking the L2 business based on NVO3 framework as an example.

The DAM module for needing to be added in operator's multicast tree can be divided into two classes --- root node and leaf node.Root Node sends BUM or user multicast flow to leaf node on (that is, in operator's multicast tree) point-to-multipoint superposition tunnel, The unicast traffic of known target MAC (Media Access Control) address is sent on point-to-point superposition tunnel.Unlike this, leaf node is in point-to-point superposition tunnel On to root node send all flows (unicast traffic including BUM flow and known target MAC Address).As shown in Figure 1 DAM model in, ERM is root node, and RAM is leaf node.

It is to be understood that not all DAM module requires to be added to operator's multicast tree.If a DAM Module is not added in any operator's multicast tree, then its all business sent and received will all be folded by point-to-point L2 Tunnel is added to carry.For example, usually control planar module (CPM) does not need to be added to any operator's multicast tree.It is flat for business For face mould block (SPM), according to concrete application, it may need not need to be added to carrier Multicast tree.For letter Change description, embodiment of the disclosure assumes that no CPM node and SPM node are added in operator's multicast tree, but only ERM It is added in operator's multicast tree with RAM.It, can be in the case where SPM and/or CPM need to be added in operator's multicast tree The mechanism of embodiment of the disclosure is easily applied to SPM and/or CPM.

Finally, the L2 superposition tunnel established will be similar to Fig. 1.The each operator's multicast tree established is with one ERM is root node, and it has the leaf node for reaching all RAM or partial RAM.It should be noted that each ERM is not another The leaf node of one ERM.After being successfully established the tunnel I-PMSI/S-PMSI, ERM must be on the tunnel I-PMSI/S-PMSI BUM and user multicast flow are sent, and RAM must receive BUM and user multicast flow on the tunnel I-PMSI/S-PMSI.

(convergence is multiple services) Fig. 2 shows several DAM modules of connection includes the correlative detail of formula operator multicast tree, It is with the root node on central node (ERM) and the leaf node in spoke nodes (RAM).Multiplexing is remotely accessed in Fig. 2 Device RAM1, RAM2 include the MAC module and L2/L3 transponder of network virtual entity (NVE), specific access technology.It is therein NVE is crucial NVO3 functional entity, is responsible for establishing and safeguards various types of network virtualization tunnels, and will come from L2/ The data of L3 transponder are encapsulated according to specified type, the DAM module for being sent to distal end by being superimposed tunnel.L2/L3 forwarding therein Device realizes the data forwarding based on layer 2 or layer 3.For example, IP operation retransmission unit and L2VPN business that it may include layer 3 turn Transmitting apparatus.And the MAC module of specific access technology therein completes user's access of physical layer.For example, the use of the physical layer Family access is above in conjunction with different access technologies described in Fig. 1.A point-to-multipoint is shown in Fig. 2 includes formula The basic flux of multicast of operator's multicast tree, all business (being IP operation and L2VPN business in the example of Fig. 2) can all carry In in operator's multicast tree, they respectively by independent virtual network context VN context ID 1 and VN context ID 2 come into Row is distinguished.

Embodiment of the disclosure is proposed for establishing the method comprising formula operator multicast tree as shown in Figure 2.It needs It is appreciated that, although being illustrate only in Fig. 2 comprising formula operator multicast tree, embodiment of the disclosure is not limited to establish packet The method of the multicast tree of operator containing formula.Moreover, it should be appreciated that when reference such as comprising formula/selecting type operator multicast tree, Polymerization connects comprising formula/selecting type operator multicast tree, operator's multicast services interface (PMSI), comprising formula operator multicast services When different types of multicast path of mouth (I-PMSI) and selecting type operator multicast services interface (S-PMSI), the disclosure Embodiment follow RFC 7117.RFC 7117 is please referred to obtain their accurate meaning.

Below in conjunction with Detailed description of the invention embodiment of the disclosure.Specifically, be shown in FIG. 3 in ERM module and The BGP signaling mechanism that the tunnel I-PMSI based on IP and compatible NVO3 is established between RAM module, more specifically, Fig. 3 is shown The BGP-VNAD-IPMSI message transmitted between network unit.And it shows in Fig. 4 between ERM module and RAM module The BGP signaling mechanism for establishing the tunnel S-PMSI based on IP and compatible NVO3, more specifically, being shown in FIG. 4 in network list The BGP-VNAD-SPMSI message transmitted between member.

Optionally, it is transmitted as shown in Figure 3 between the network unit (including ERM, RAM etc.) in the DAM system At least one of BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message as shown in Figure 4, to establish the fortune Seek quotient's multicast tree；Wherein the BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message include following attribute: MP_ REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulate extended community attribute.

Optionally, by the MP_REACH_NLRI attribute, to issue up to the purpose network information and corresponding next-hop Information, and transmit the virtual network context identifier ID under VN example；Operation is carried by the PMSI_TUNNEL attribute Quotient's multicast services interface tunnel information；And extended community attribute is encapsulated to indicate stacking network tunnel encapsulation by the BGP Tunnel type.

As described above, the BGP-VNAD-IPMSI message and BGP-VNAD-SPMSI message that newly define at least may include down Five attributes of column:

● MP_REACH_NLRI attribute

● PMSI_TUNNEL attribute

● L2VPN identifier extension group attribute

● BGP encapsulates extended community attribute

● route target extended community attribute

This five attributes are carried out respectively below in conjunction with BGP-VNAD-IPMSI message and BGP-VNAD-SPMSI message Description:

MP_REACH_NLRI attribute

The format of the MP_REACH_NLRI attribute of BGP-VNAD-IPMSI message and BGP-VNAD-SPMSI message is different 's.

(1) the MP_REACH_NLRI attribute of BGP-VNAD-IPMSI message

The Address-Family Identifier symbol (AFI) and subaddressing that the MP_REACH_NLRI attribute of BGP-VNAD-IPMSI message uses In race's identifier (SAFI) and RFC 6074 (and to include the discovery/binding automatically of formula operator multicast tree in RFC 7117) Used Address-Family Identifier symbol (AFI) and subaddressing race identifier (SAFI) are identical, i.e. AFI=25 (L2VPN), SAFI=65 (VPLS).However, the coded format of NLRI field therein is but different from coded format used in RFC 6074.In addition to VN Except automatic discovery, which also indicates VN context ID (VN Context ID) by signaling.

It should be noted that the NLRI of this format is initially defined on same inventor entitled, " a kind of distribution is connect Enter multiplexer DAM stacking network system and its apparatus " first application for a patent for invention in.In embodiment of the disclosure, new This format of NLRI has been reused in the BGP-VNAD-IPMSI message of definition.

(2) the MP_REACH_NLRI attribute of BGP-VNAD-SPMSI message

The MP_REACH_NLRI attribute of BGP-VNAD-SPMSI message has reused being directed in RFC 7117 defined " finding routing MCAST-NLRI automatically to S-PMSI " is (that is, AFI=25 (L2VPN), SAFI=8 (MCAST-VPLS), routing Type=3 (S-PMSI has found to route automatically)) same format that is encoded.Detail please refers to RFC 7117.

PMSI_TUNNEL attribute

The coded format of PMSI_TUNNEL attribute is initially defined in RFC 6514, and to it in RFC 7117 It is reused.Similar to RFC 7117, embodiment of the disclosure is reused the attribute to carry PMSI tunnel information. Be shown in FIG. 5 the coded format of PMSI_TUNNEL attribute, the coded format replicated from RFC 6514 and carried out compared with Small modification.

Optionally, pass through attribute field, tunnel-like type-word included in above-mentioned modified PMSI_TUNNEL attribute The tunnel identifier field of section, VN context ID field and variable-length, to carry the PMSI tunnel information.

As described above, replicating the coded format of PMSI_TUNNEL attribute from RFC 6514 and having carried out lesser repair Change, for example, " VN context ID " field in Fig. 5 is initially named as " MPLS label " in RFC 6514.However, in Fig. 5 In, which is referred to as " VN context ID ", is used to carry with the PMSI_TUNNEL attribute indicated in embodiment of the disclosure Point-to-multipoint NVO3 is superimposed the information in tunnel, rather than for carrying the IETF L2VPN/L3VPN multicast information based on MPLS.

In the initially PMSI_TUNNEL attribute as defined in RFC 6514, by " MPLS label " word of 3 octets Section is limited to only carry the value of 20 bits, eliminates this limitation in embodiment of the disclosure, so that it be allowed to carry 24 ratios Any one of paricular value or 20 bit values.In embodiment of the disclosure, according to the superposition tunnel type of NVO3,38 words " VN context ID " field of section can carry the VXLAN network identifier of 24 bits in the superposition tunnel for VXLAN (VNI) it or carries the virtual subnet identifier (VSID) for 24 bits in NVGRE superposition tunnel or carries in GRE Encapsulate the MPLS service label of 20 bits in the superposition tunnel of MPLS.When " VN context ID " code field of this 3 octets When the MPLS service label of 20 bits, 20 high-order bits are only used only, and remain 4 bits of low level and should be set Be set to zero, this in RFC 6514 defined it is consistent.

For " tunnel type (Tunnel Type) " field in Fig. 5, RFC 7117 value therein is limited to can only be 0, one in 1,2 or 6, these values correspond respectively to " there is no tunnel information ", " RSVP-TE P2MP LSP ", " LDP P2MP LSP " and " entrance duplication ".That is, RFC 7117 does not support any PMSI tunnel based on IP and compatible NVO3 Road.In order to support the PMSI tunnel type based on IP and compatible NVO3, embodiment of the disclosure to allow in PMSI_TUNNEL attribute " tunnel type " value be arranged to 3 (PIM-SSM trees) or 4 (PIM-SM trees).Therefore, optionally, the tunnel type field It is arranged to support to establish the multicast tree of the Protocol Independent Multicast in designated multicast source.Also, optionally, the tunnel type field It is arranged to support to establish the multicast tree of the Protocol Independent Multicast of sparse mode.

Although should be noted that and define PMSI tunnel type 3 and 4 in interconnection network data distributor gear (IANA), But it is but specifically defined as being used for the BGP coding of BGP/MPLS IP-VPN multicast in RFC 6514.In other words, such as Fruit is without appropriate extension as disclosed herein, then it is by cannot be with the L2VPN NLRI (AFI=of VPLS multicast 25, SAFI=65 or 8) it is combined use.Embodiment of the disclosure allows PMSI tunnel type 3 (PIM-SSM tree) and type 4 (PIM-SM tree) and L2VPN NLRI are combined uses, and describe these new PMSI tunnel types and L2VPN NLRI into The appropriate ways that row is applied in combination.

As described above, because RFC 7117 is only supported using MPLS service label as the polymerization operator multicast based on MPLS The demultiplexing symbol in (that is, RSVP-TE or mLDP P2MP LSP) is set, is belonged to so PMSI_TUNNEL is used only in RFC 7117 A tunnel type field in property specifies operator's multicast tree to be sufficient.However, used in DAM based on IP and In the point-to-multipoint superposition tunnel of compatible NVO3, it is not enough to refer to using a tunnel type field in PMSI_TUNNEL attribute Determine institute's necessary information required for leaf node decapsulates the multicast service of tunnelling.In addition to specifying operator external group It broadcasts except tree type (for example, PIM-SSM tree or PIM-SM tree), it is also necessary to which specified leaf node solves received grouping Encapsulate and restore the inside VN encapsulated type of original BUM frame or user multicast grouping.This passes through the BGP encapsulation newly introduced and expands Group attribute is opened up to realize.Referring to BGP encapsulation extended community hereinafter to obtain detail.

L2VPN identifier extension group

As described in RFC 6074 and RFC 7117, L2VPN identifier extension group is also provided in bgp update message Body, meaning, use and coded format in RFC 6074 defined it is identical.In DAM model, these L2VPN identifiers Extended community indicates L2VPN example corresponding to corresponding BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message, because This, can be envisioned for in each DAM module specific VN example (for example, IP operation example as described in figure 2 or L2VPN srvice instance) it is identified.This value must be locally configured in each DAM module network virtual physically.It can make With such as in RFC 6074 any one of two kinds of canonical forms of defined canonical form come to L2VPN identifier extension group Body is encoded.

If should be noted that VN context ID indicates to be respectively VNI or the VSID etc. in VXLAN or NVGER network The VN identifier of global sense, then one-to-one reflect will be present between the value of L2VPN identifier and the value of VN context ID It penetrates, although L2VPN identifier and VN context ID have different field length, they all uniquely identify VN example.

BGP encapsulates extended community

It is not deposited in any bgp update message of existing VPLS multicast (RFC 7117) and BGP-AD (RFC 6074) Extended community is encapsulated in BGP.RFC 7117 and RFC 6074 cannot indicate the tunnel type of BGP tunnel encapsulation by signaling. That is, VN context ID is the MPLS service label of local sense always in RFC 7117.BGP encapsulates extended community It is initially defined in RFC 5512, is the opaque extended community of BGP (type is 0x030c), to indicate tunnelling Tunnel type used in frame/grouping encapsulation.In embodiment of the disclosure, initially only support correspond respectively to VXLAN, NVGRE and the tunnel type 8,9,11 that MPLS is encapsulated in GRE.Therefore, optionally, the BGP encapsulates extended community attribute It is arranged to support virtual expansible local area network.Optionally, the BGP encapsulation extended community attribute is arranged to support using logical With the network virtualization of routed encapsulation.Also, optionally, the BGP encapsulation extended community attribute is arranged to support general Multiprotocol label switching is encapsulated in routed encapsulation.

In brief, " BGP encapsulates extended community " combines " tunnel type " field in PMSI_TUNNEL attribute, uniquely Ground specifies following content: (1) operator's multicast tree (one in PIM-SSM tree or PIM-SM tree based on IP and compatible NVO3 Kind)；And the encapsulated type (VXLAN, NVGRE or one of MPLS is encapsulated in GRE) in (2) NVO3 superposition tunnel.

It is suitable for DAM superposition tunnel it should be noted that up to the present only having VXLAN, NVGRE or encapsulating MPLS in GRE Road.New tunnel type is currently studied by IETF NVO3 working group.If IETF receives any new tunnel-like Type, then embodiment of the disclosure easily can encapsulate extended community by using BGP to extend to other new The support of NVO3 superposition tunnel type.

Route target extended community

Route target (RT) extended community is extended with route target (RT) used in RFC 7117 and/or RFC 6074 Group is identical.It is the standard extension group all occurred in the bgp update message of many applications；Its meaning is used and is encoded Format in RFC 6074 defined it is identical.It is not described in detail in embodiment of the disclosure.

Other than above-mentioned five crucial bgp attributes, other bgp attributes suitably can also be added to BGP more In new information.Embodiment of the disclosure does not list these attributes because the VN in these attributes and DAM model find automatically and I-PMSI/S-PMSI signaling is unrelated.

In DAM model, when ERM needs to carry out following operation --- that is, it needs to:

(1) its VN member relation is indicated to other DAM modules by signaling, to establish point-to-point NVO3 L2 superposition When tunnel；And

(2) I-PMSI tunnel information is indicated to RAM by signaling, when establishing the point-to-multipoint tunnel I-PMSI；

ERM should declare bgp update message (the bgp update message on the right side of Fig. 3) as illustrated in fig. 3.In the disclosure Embodiment in, the bgp update message of this format is referred to as BGP-VNAD-IPMSI message, in a bgp update message In simultaneously support VN to find signaling and I-PMSI signaling automatically.

It should be noted that when RAM (or the CPM or SPM for not being added to any operator's multicast tree) need by its VN at Member's relationship is indicated to other DAM modules by signaling, to establish point-to-point NVO3 L2 superposition tunnel (that is, VN has found automatically) When, it should declare bgp update message (being indicated with grey) as shown in the left side of Fig. 3.The bgp update message of this format exists The first patent of invention of entitled " a kind of distribution couple in multiplexer DAM stacking network system and its apparatus " of same inventor It is defined in application, no longer it is described in detail in embodiment of the disclosure.In embodiment of the disclosure, this The bgp update message of kind format will be referred to as BGP-VNAD-ONLY message.

Similarly, in the DAM model, when ERM needs S-PMSI tunnel information being indicated to RAM by signaling, to When establishing the point-to-multipoint tunnel S-PMSI, ERM should declare bgp update message as illustrated in fig. 4.In embodiment of the disclosure In, this bgp update message is referred to as BGP-VNAD-SPMSI message.

It should be noted that the tunnel S-PMSI is used to transmit specific user multicast stream, these specific user multicasts Stream is usually specific user's multicast stream of high data volume and establishes.Detail please refers to RFC 7117.

The process for establishing these tunnels PMSI is similar with the process of defined in RFC 7117, but carries out to RFC 7117 Following modification:

(1) it is extended to and supports PMSI tunnel type 3 and type 4, so that PIM-SSM tree and/or PIM-SM tree It can be set up as including formula/selecting type operator multicast tree.

(2) format of bgp update message is modified.New BGP encapsulation extension group is added in bgp update message Body (is initially defined in RFC 5512, but is reused in embodiment of the disclosure), to indicate that the encapsulation of traffic frame is made BGP encapsulation tunnel type.In embodiment of the disclosure, it supports BGP encapsulation tunnel type 8,9,11, corresponds respectively to VXLAN, NVGER and MPLS is encapsulated in GRE.

It should be noted that as shown in figure 5, RFC 7117 is by " tunnel type (Tunnel Type) " field therein Value is limited to be one in 0,1,2 or 6, these values correspond respectively to " tunnel information is not present ", " RSVP-TE P2MP LSP ", " LDP P2MP LSP " and " entrance duplication ".Therefore, RFC 7117 is merely capable of establishing the operator based on MPLS Multicast tree (RSVP-TE or mLDP P2MP LSP).So needing to be extended RFC 7117, to establish between DAM module Operator's multicast tree based on IP and compatible NVO3.

Following pseudo Algorithm shows how MP-BGP processing routine can extend to support based on IP and be compatible with NVO3's The tunnel I-PMSI and the tunnel S-PMSI.

If L is the value of the Length subfield of VPLS NLRI (AFI=25, SAFI=65), Route_Type MCAST- The value of the route-type subfield of VPLS NLRI (AFI=25, SAFI=8), PMSI_Tunnel_Type PMSI_TUNNEL The value of the subfield of the tunnel type of attribute.

NVO3 is point-to-point and/or point-to-multipoint is superimposed the topology in tunnel by BGP-VNAD-ONLY message, BGP-VNAD- Route target extended community (also referred to as output RT) in IPMSI message and BGP-VNAD-SPMSI message and it is directed to DAM The input route target (input RT) that each VN example in module is configured is controlled.Embodiment of the disclosure is not detailed Carefully illustrate the mechanism of this standard.When output RT value and the combination for inputting RT value allow BGP-VNAD-IPMSI message or BGP- When VNAD-SPMSI message is imported into the VN example on a DAM module (that is, leaf node), following letter can be therefrom extracted Breath:

(1) type (one of PIM-SSM tree or PIM-SM tree) of operator's multicast tree based on IP and compatible NVO3

(2) NVO3 is superimposed the type (VXLAN, NVGRE or one of MPLS is encapsulated in GRE) in tunnel

(3) parameter (system ip address of root node and the group IP address of operator's multicast tree) of operator's multicast tree

(4) to BUM flow or the user multicast flow VN context ID that is demultiplexed from operator's multicast tree It is worth (it is to be noted that operator's multicast tree is non-polymeric if context ID=0)

(5) in the case where S-PMSI message, user multicast stream (is marked by user multicast source address and group IP address Know) it is tied to selecting type operator multicast tree

After BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message are successfully decoded, DAM module is answered PIM-SSM or PIM-SM tree should be added immediately by sending IGMP (Internet Group Management Protocol) addition message, and prepare (optionally being demultiplexed) BUM stream or user multicast stream are received comprising formula or selecting type operator multicast tree from what is established. Embodiment of the disclosure is not described in detail it.

Fig. 6 shows the equipment 600 in DAM system according to an embodiment of the present disclosure.Equipment 600 includes processing unit 601, processing unit 601 establishes the various methods of operator's multicast tree to execute in DAM system as described above.

Optionally, processing unit 601 is to transmit in BGP message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI extremely Lack one kind, to establish operator's multicast tree；Wherein the BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message Comprising with properties: MP_REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulate extended community attribute.

Optionally, processing unit 601 is by the MP_REACH_NLRI attribute, issuing up to the purpose network information and Corresponding next hop information, and transmit the virtual network context identifier ID under VN example；Belonged to by the PMSI_TUNNEL Property carries PMSI tunnel information；And extended community attribute is encapsulated to indicate stacking network tunnel encapsulation by the BGP Tunnel type.

Optionally, the BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI that processing unit 601 is transmitted Message also includes L2VPN identifier extension group attribute and route target extended community attribute.

Optionally, processing unit 601 is identified by the L2VPN identifier extension group attribute in the DAM system Specific virtual network example；And the topology in stacking network tunnel is controlled by the route target extended community attribute Structure.

In conclusion the following mechanism for DAM model has been proposed in embodiment of the disclosure.

Two kinds of new bgp update message formats are proposed, are referred to as BGP-VAND-IPMSI in embodiment of the disclosure Message and BGP-VNAD-SPMSI message, by the root node (that is, ERM) of operator's multicast tree in the DAM model declare this two Kind message finds to disappear with the instruction of the signaling of I-PMSI or to bgp update automatically for carrying out VN in a bgp update message S-PMSI signaling instruction in breath.The BGP-VAND-IPMSI message and BGP-VNAD-SPMSI message proposed can with it is same A kind of first application for a patent for invention (entitled " distribution couple in multiplexer DAM stacking network system and its apparatus ") of inventor Proposed in BGP-VNAD-ONLY message coexist, the BGP-VNAD-ONLY message is by being added without in operator's multicast tree Leaf node (that is, RAM, CPM, SPM) declared.

It include briefly formula/selection to how to establish carry BUM business and user multicast service in DAM model Formula operator multicast tree is described.However, it is desirable to be appreciated that, embodiment of the disclosure scope of the claimed is only by weighing The content that benefit requires limits.

Claims

1. a kind of method for establishing operator's multicast tree in distributed couple in multiplexer DAM system, comprising:

Between the network unit in the DAM system transmit Border Gateway Protocol (BGP) message BGP-VNAD-IPMSI message or At least one of BGP-VNAD-SPMSI message, to establish operator's multicast tree；

Wherein the BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message include following attribute:

MP_REACH_NLRI attribute, PMSI_TUNNEL attribute and BGP encapsulate extended community attribute.

2. according to the method described in claim 1, wherein:

By the MP_REACH_NLRI attribute, to issue up to the purpose network information and corresponding next hop information, and transmit Virtual network context identifier ID under virtual network VN example；

Operator's multicast services interface PMSI tunnel information is carried by the PMSI_TUNNEL attribute；And

Extended community attribute is encapsulated by the BGP to indicate the tunnel type of stacking network tunnel encapsulation.

3. according to the method described in claim 1, wherein:

When transmitting the BGP-VNAD-IPMSI message between the network unit, VN context ID field is included in described In MP_REACH_NLRI attribute, to distinguish different VN contexts.

4. according to the method described in claim 3, wherein:

By attribute field included in the PMSI_TUNNEL attribute, tunnel type field, VN context ID field, with And the tunnel identifier field of variable-length, to carry the PMSI tunnel information.

5. according to the method described in claim 4, wherein:

The tunnel type field is arranged to support to establish the multicast tree of the Protocol Independent Multicast in designated multicast source.

6. according to the method described in claim 4, wherein:

The tunnel type field is arranged to support to establish the multicast tree of the Protocol Independent Multicast of sparse mode.

7. the method according to any one of claim 5-6, in which:

The BGP encapsulation extended community attribute is arranged to support virtual expansible local area network.

8. the method according to any one of claim 5-6, in which:

The BGP encapsulation extended community attribute is arranged to the network virtualization for supporting to use generic route encapsulation.

9. the method according to any one of claim 5-6, in which:

The BGP encapsulation extended community attribute is arranged to support to encapsulate multiprotocol label switching in generic route encapsulation.

10. according to the method described in claim 1, wherein:

The BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message also include 2 Virtual Private Network L2VPN of layer mark Know symbol extended community attribute and route target extended community attribute.

11. according to the method described in claim 10, wherein:

The specific virtual network example in the DAM system is identified by the L2VPN identifier extension group attribute；And

The topological structure in stacking network tunnel is controlled by the route target extended community attribute.

12. a kind of equipment for establishing operator's multicast tree in distributed couple in multiplexer DAM system, comprising:

Processing unit, for transmitting Border Gateway Protocol (BGP) message BGP- between the network unit in the DAM system At least one of VNAD-IPMSI message or BGP-VNAD-SPMSI message, to establish operator's multicast tree；

13. equipment according to claim 12, in which:

The processing unit is by the MP_REACH_NLRI attribute, to issue up to the purpose network information and corresponding next Hop-information, and transmit the virtual network context identifier ID under virtual network VN example；Pass through the PMSI_TUNNEL attribute To carry operator's multicast services interface PMSI tunnel information；And extended community attribute is encapsulated to indicate to fold by the BGP The tunnel type of screening network tunnel encapsulation.

14. equipment according to claim 12, in which:

When the processing unit transmits the BGP-VNAD-IPMSI message between the devices, by VN context ID field Included in the MP_REACH_NLRI attribute, to distinguish different VN contexts.

15. equipment according to claim 14, in which:

16. equipment according to claim 15, in which:

17. equipment according to claim 15, in which:

18. equipment described in any one of 6-17 according to claim 1, in which:

19. equipment described in any one of 6-17 according to claim 1, in which:

20. equipment described in any one of 6-17 according to claim 1, in which:

21. equipment according to claim 12, in which:

The BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message that the processing unit is transmitted also includes 2 Virtual Private Network L2VPN identifier extension group attribute of layer and route target extended community attribute.

22. equipment according to claim 21, in which:

The processing unit is identified specific virtual in the DAM system by the L2VPN identifier extension group attribute Network example；And the topological structure in stacking network tunnel is controlled by the route target extended community attribute.