CN106992935A

CN106992935A - The method and apparatus that operator's multicast tree is set up in DAM systems

Info

Publication number: CN106992935A
Application number: CN201610038177.XA
Authority: CN
Inventors: 张立新
Original assignee: Alcatel Lucent Shanghai Bell Co Ltd
Current assignee: Nokia Shanghai Bell Co Ltd
Priority date: 2016-01-20
Filing date: 2016-01-20
Publication date: 2017-07-28
Anticipated expiration: 2036-01-20
Also published as: CN106992935B

Abstract

Embodiment of the disclosure provides a kind of method and apparatus that operator's multicast tree is set up in DAM systems, and methods described includes：At least one of Border Gateway Protocol (BGP) message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI are transmitted between NE in the DAM systems, to set up operator's multicast tree；Wherein described BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message packages contain with properties：MP_REACH_NLRI attributes, PMSI_TUNNEL attributes and BGP encapsulation extended community attributes.

Description

The method and apparatus that operator's multicast tree is set up in DAM systems

Technical field

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

Background technology

Embodiment of the disclosure technical problem to be solved comes from distributed couple in multiplexer (DAM) model.Before specific technical problem is discussed, first introduce DAM's Some background technologies.

Put it briefly, DAM is a kind of access device, it is any type of " empty by having interconnected The distributed module of link " is constituted." virtual link " is referred to be built on layer 3 (L3) bottom-layer network Vertical layer 2 (L2) superposition tunnel.L2 superpositions tunnel can be point-to-point tunneling and point pair Multipoint channel.Fig. 1 shows DAM logical model.

Fig. 1 shows distributed DAM deployment model, wherein mainly including 4 generic modules： Edge router module (ERM modules), it runs internetwork-ing/multiprotocol label switching (IP/MPLS) data plane functions；Control plane module (CPM modules), it runs control Plane processed and management plane function；Service plane module (SPM), it runs business and application Function；Remote access module (RAM module), the module is located at close to the position of user, And various specific Access Layer technologies are terminated, for example, the various specific Access Layer skills Art is：Cable access technology based on DOCSIS (data over cable service interface specification), The light of ethernet passive optical network (EPON) and Gigabit-capable Passive Optical Network (GPON) Access technology or various types of Digital Subscriber Line xDSL access technologies, RAM module pair Unified Ethernet interface is presented in network side.

All center modules (ERM, CPM and SPM) constitute net each other in Fig. 1 Shape topology, i.e., they can be directly transmitted and received data packet between any two, their conducts One entirety, constitutes distribution DAM center.And all RAM modules constitute DAM The spoke of system, i.e., each RAM module is only capable of directly transmitting and receiving between center module Packet, RAM module can not be directly transmitted and received data packet between any two.Moreover, logical Cross and build a stacking network on bottom transmission network (generally Ethernet or IP network), All modules of DAM systems can be mutually unified into an entirety, the part of module shown in Fig. 1 can Virtually to turn to the software run on standard server or data center's virtual machine.

Many kinds of stacking networks are presently, there are, for example, operator backbone bridge joint network (is also claimed Make the network of the encapsulation MAC in the medium access control (MAC)), the layer based on MPLS 2 Virtual Private Networks (L2VPN) or the Virtual Private Network of layer 3 (L3VPN).In order to obtain more Good expandability, embodiment of the disclosure assume bottom-layer network be Pure IP network (i.e., Ethernet and MPLS bottom-layer networks it are not related to).Because embodiment of the disclosure is only focusing only on In terms of DAM, so it is simultaneously it is also assumed that stacking network provides L2 services, specifically, It is assumed that the payload in L2 superpositions tunnel is the ethernet frames of IEEE 802.3 (that is, the disclosure Embodiment is not related to L3 stacking networks).Network virtualization (IETF NVO3) on IETF layers 3 The documents such as the RFC 7365 and draft-ietf-nvo3-arch of working group, which are provided, to be used for describing L3 The general infrastructure component of L2 and L3 stacking networks on bottom-layer network and term, therefore, Embodiment of the disclosure refer to IETF NVO3 infrastructure component and term to describe in large quantities DAM models.

Although embodiment of the disclosure refer to IETF NVO3 infrastructure component and art in large quantities Language, it is noted that the application scenarios and IETF NVO3 of embodiment of the disclosure Application scenarios between there is significant difference.IETF NVO3 frameworks are for data center Network virtualization and design, the enormous amount of L2 stacking networks therein and be in nature dynamic 's.But in DAM models, the quantity of L2 stacking networks is very limited and is in nature Relative quiescent.The property of L2 stacking networks in DAM models is very similar to IETF L2VPN, but IETF L2VPN are only supported in MPLS and encapsulate MPLS or general Encapsulation MPLS L2 superpositions tunnel in routed encapsulation (GRE), without supporting DAM moulds The superpositions of the L2 based on IP and compatibility NVO3 tunnel required in type.Therefore, the disclosure The target of embodiment can be counted as being extended IETF L2VPN technologies supporting NVO3 L2 are superimposed tunnel.

It should be noted that in embodiment of the disclosure, NVO3 L2 superpositions tunnel is referred to Any L2 that can be supported by IETF NVO3 frameworks set up on IP bottom-layer networks is folded Plus tunnel.Currently the tunnel type in most widely used IETF NVO3 L2 stacking networks is Virtual expansible LAN (VXLAN) in RFC 7348, draft-sridharan- The network virtualization of use generic route encapsulation in virtualization-nvgre documents (NVGER) MPLS, and these tunnels are encapsulated in GRE and in RFC 4023 The default tunnel type that will be used in DAM models is also contains in road type.

In the DAM models shown in Fig. 1, an important technical problem is to set up operator Multicast tree come effectively transmit from Centroid to spoke nodes (for example, from ERM modules to RAM module) multicast (and broadcast) flow.Flux of multicast include basic flux of multicast and/ Or User IP multicast (user multicast) flow.In embodiment of the disclosure, basic multicast Flow is referred to by agreement institutes such as address resolution protocol (ARP), Network findings (ND) The broadcasting of generation, the flow of unknown and multicast (BUM) Ether frame.

In short, embodiment of the disclosure attempts the virtual private to defined in RFC 7117 The multicast mechanism of LAN services (VPLS) is extended, so as to be applied to DAM Model, is found and comprising formula/selecting type operator automatically with carrying out virtual network (VN) example The foundation of multicast tree, so as to more effectively transmit BUM flows and/or user multicast stream Amount.

Currently, except some in draft-ietf-nvo3-mcast-framework documents are general Outside discussion, also not used for IETF NOV3 networks formal standard multicast solution party Case.It might be that NVO3 multicasting solutions will be based on central server.So And, due to the L2 stacking networks used in DAM models will be similar to it is traditional L2VPN, so embodiment of the disclosure is based on to the VPLS multicasts solution in RFC 7117 Scheme is extended to design DAM multicasting solutions.

At this stage, RFC 7117 is the standard for the transport multicast flow in VPLS network Solution.Unfortunately, RFC 7117 only supports the multicast tunnel based on MPLS Road, for example by RSVP-traffic engineering (RSVP-TE) set up it is point-to-points Point (P2MP) label switched path (LSP), or extended by the multiple spot of tag distribution protocol (mLDP) the P2MP LSP set up, and the deployment DAM's assumed at us is pure These Multicast Tunnel can not be set up in IP bottom-layer networks.

May be referred to same inventor it is entitled " a kind of distributed couple in multiplexer DAM fold The first applications for a patent for invention of screening network system and its apparatus " obtains the technology that other are related Content.

The content of the invention

According to an aspect of this disclosure, there is provided operator's multicast is set up in DAM systems The method of tree, including：Borde gateway is transmitted between NE in the DAM systems At least one in agreement BGP message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI Kind, to set up operator's multicast tree；Wherein described BGP-VNAD-IPMSI message Contain with the BGP-VNAD-SPMSI message packages with properties：MP_REACH_NLRI Attribute, PMSI_TUNNEL attributes and BGP encapsulation extended community attributes.Need note BGP in meaning, embodiment of the disclosure refers to multi-protocols extending boundary gateway protocol (MP-BGP)。

Alternatively, by the MP_REACH_NLRI attributes, to issue up to purpose net Network information and corresponding next hop information, and transmit the virtual network context under VN examples Identifier ID；Connect by the PMSI_TUNNEL attributes to carry operator's multicast services Mouth (PMSI) tunnel information；And, encapsulate extended community attribute to refer to by the BGP Show the tunnel type of stacking network tunnel encapsulation.

Alternatively, the BGP-VNAD-IPMSI message is transmitted between the NE When, VN context ID fields are included in the MP_REACH_NLRI attributes, The VN context different to distinguish.

Alternatively, by the attribute field included in the PMSI_TUNNEL attributes, The tunnel identifier word of tunnel type field, VN context ID fields and variable-length Section, to carry the PMSI tunnel informations.

Alternatively, the tunnel type field is arranged to the association for supporting to set up designated multicast source Discuss the multicast tree of independent multicast (PIM-SSM).

Alternatively, the tunnel type field is arranged to support the agreement for setting up sparse mode The multicast tree of independent multicast (PIM-SM).

Alternatively, the BGP encapsulation extended community attribute is arranged to support virtual expansible LAN.

Alternatively, the BGP encapsulation extended community attribute is arranged to support to use general road By the network virtualization encapsulated.

Alternatively, the BGP encapsulation extended community attribute is arranged to support in general route Multiprotocol label switching is encapsulated in encapsulation.

Other side in accordance with an embodiment of the present disclosure, the BGP-VNAD-IPMSI disappears Breath and the BGP-VNAD-SPMSI message also belong to comprising L2VPN identifier extensions group Property and route target extended community attribute.

Alternatively, the DAM is identified by the L2VPN identifier extensions group attribute Specific virtual network example in system；And, belonged to by the route target extended community Property controls the topological structure in stacking network tunnel.

According to another aspect of the disclosure, there is provided the equipment in a kind of DAM systems, bag Include：To transmit BGP message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI At least one of, the processing unit to set up operator's multicast tree；It is wherein described BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message packages contain with subordinate Property：MP_REACH_NLRI attributes, PMSI_TUNNEL attributes and BGP encapsulation Extended community attribute.

Alternatively, the processing unit is by the MP_REACH_NLRI attributes, to send out Cloth transmits the void under VN examples up to the purpose network information and corresponding next hop information Intend network context identifier ID；PMSI is carried by the PMSI_TUNNEL attributes Tunnel information；And, encapsulate extended community attribute to indicate stacking network by the BGP The tunnel type of tunnel encapsulation.

Alternatively, when the processing unit transmits described between the NE During BGP-VNAD-IPMSI message, VN context ID fields are included in described In MP_REACH_NLRI attributes, the VN context different to distinguish.

Alternatively, the tunnel type field is arranged to the association for supporting to set up designated multicast source Discuss the multicast tree of independent multicast.

Alternatively, the tunnel type field is arranged to support the agreement for setting up sparse mode The multicast tree of independent multicast.

Other side in accordance with an embodiment of the present disclosure, the institute that the processing unit is transmitted State BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message is also included L2VPN identifier extensions group attribute and route target extended community attribute.

Alternatively, the processing unit by the L2VPN identifier extensions group attribute come Identify the specific virtual network example in the DAM systems；And, pass through the route mesh Extended community attribute is marked to control the topological structure in stacking network tunnel.

As described above, embodiment of the disclosure is to multicasting solution specified in RFC 7117 Extended, pure IP bottom-layer networks can be applied to.Moreover, in the disclosure This extension proposed in embodiment remains what can be reused in RFC 7117 as much as possible Existing mechanism and process.

Brief description of the drawings

Fig. 1 shows DAM models；

Fig. 2, which is shown, includes formula operator multicast tree between DAM modules；

Fig. 3 shows the BGP signalings for including formula operator multicast tree for DAM；

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

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

Fig. 6 shows the equipment in DAM systems in accordance with an embodiment of the present disclosure.

Embodiment

, will be with reference to composition a part of this disclosure in the specific descriptions of following optional embodiment Accompanying drawing.Each accompanying drawing, which has been illustrated by way of example, can realize the specific reality of the disclosure Apply example.However, it is desirable to be appreciated that, example embodiment is not intended as limit according to the disclosure All embodiments.

Following examples are using IETF NVO3 framework and term come to distributed access multiplexing Device illustrates, and illustrates by taking the L2 business based on NVO3 frameworks as an example.

The DAM modules being added in operator's multicast tree can will be needed to be divided into two classes --- root Node and leaf node.Root node is on point-to-multipoint superposition tunnel (that is, in operator's multicast On tree) BUM or user multicast flow are sent to leaf node, sent out on point-to-point superposition tunnel Send the unicast traffic of known target MAC (Media Access Control) address.Unlike this, leaf node is in point-to-point superposition On tunnel all flow (including BUM flows and known target MAC are sent to root node The unicast traffic of address).In DAM models as shown in Figure 1, ERM is root node, RAM is leaf node.

It is to be understood that not all DAM modules are required for being added to operator's group Broadcast tree.If a DAM module is not added in any operator's multicast tree, then its All business sent and received will all be carried by point-to-point L2 superpositions tunnel.For example, logical Normal control plane module (CPM) need not be added to any operator's multicast tree.For industry It is engaged in for planar module (SPM), according to concrete application, it may need to be not required to It is added to carrier Multicast tree.In order to simplify description, embodiment of the disclosure assumes do not have CPM nodes and SPM nodes are added in operator's multicast tree, but only ERM and RAM is added in operator's multicast tree.Need to be added to operator in SPM and/or CPM In the case of in multicast tree, easily the mechanism of embodiment of the disclosure can be applied to SPM and/or CPM.

Finally, the L2 superpositions tunnel set up will be similar to Fig. 1.The each fortune set up Business's multicast tree is sought all using an ERM as root node, and it has all RAM of arrival or portion Divide RAM leaf node.It should be noted that each ERM is not another ERM Leaf node.After I-PMSI/S-PMSI tunnels are successfully established, ERM must be Send BUM and user multicast flow on I-PMSI/S-PMSI tunnels, and RAM must be BUM and user multicast flow are received on I-PMSI/S-PMSI tunnels.

Fig. 2 shows that (convergence is multiple services) of some DAM modules of connection includes formula operation The correlative detail of business's multicast tree, it has the root node and spoke on Centroid (ERM) Leaf node on bar node (RAM).Multiplexer RAM1, RAM2 are remotely accessed in Fig. 2 MAC module and L2/L3 comprising network virtual entity (NVE), specific access technology Transponder.NVE therein is crucial NVO3 functional entitys, is responsible for setting up and safeguards each The network virtualization tunnel of type, and by the data from L2/L3 transponders according to finger Determine type package, the DAM modules of distal end are sent to by being superimposed tunnel.L2/L3 therein Transponder realizes the data forwarding based on layer 2 or layer 3.For example, it can include layer 3 IP operation retransmission unit and L2VPN business retransmission devices.And specific access technology therein MAC module completes user's access of physical layer.For example, user's access of the physical layer is Above in conjunction with the different access technologies described by Fig. 1.A point is shown in fig. 2 Formula operator multicast tree is included to multiple spot, all business (are IP industry in Fig. 2 example Business and L2VPN business) basic flux of multicast can all be carried in operator's multicast tree, They are respectively by independent virtual network context VN context IDs 1 and VN context IDs 2 To make a distinction.

Embodiment of the disclosure is proposed as shown in Figure 2 includes formula operator group for setting up The method for broadcasting tree.Although it is to be understood that illustrate only in Fig. 2 comprising formula operator Multicast tree, but embodiment of the disclosure is not limited to set up the side for including formula operator multicast tree Method.Moreover, it should be appreciated that when quote such as comprising formula/selecting type operator multicast tree, Polymerization comprising formula/selecting type operator multicast tree, operator's multicast services interface (PMSI), Include formula operator multicast services interface (I-PMSI) and selecting type operator multicast services During different types of multicast path of interface (S-PMSI), embodiment of the disclosure follows RFC 7117.RFC 7117 is refer to obtain their accurate meaning.

Below in conjunction with brief description of the drawings embodiment of the disclosure.Specifically, figure 3 illustrates For being set up between ERM modules and RAM module based on IP and compatibility NVO3 The BGP signaling mechanisms in I-PMSI tunnels, more specifically, Fig. 3 show NE it Between the BGP-VNAD-IPMSI message transmitted.And shown in Fig. 4 in ERM moulds The BGP in the S-PMSI tunnels based on IP and compatibility NVO3 is set up between block and RAM module Signaling mechanism, more specifically, figure 4 illustrates between the network elements transmit BGP-VNAD-SPMSI message.

Alternatively, the NE in the DAM systems (including ERM, RAM etc.) Between transmit BGP-VNAD-IPMSI message as shown in Figure 3 or as shown in Figure 4 At least one of BGP-VNAD-SPMSI message, to set up operator's multicast Tree；Wherein described BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI disappear Breath is included with properties：MP_REACH_NLRI attributes, PMSI_TUNNEL attributes, And BGP encapsulation extended community attributes.

Alternatively, by the MP_REACH_NLRI attributes, to issue up to purpose net Network information and corresponding next hop information, and transmit the virtual network context under VN examples Identifier ID；Connect by the PMSI_TUNNEL attributes to carry operator's multicast services Mouth tunnel information；And, encapsulate extended community attribute to indicate overlay network by the BGP The tunnel type of network tunnel encapsulation.

As described above, the BGP-VNAD-IPMSI message newly defined and BGP-VNAD-SPMSI message can at least include following five attributes：

● MP_REACH_NLRI attributes

● PMSI_TUNNEL attributes

● L2VPN identifier extension group attributes

● BGP encapsulates extended community attribute

● route target extended community attribute

Below in conjunction with BGP-VNAD-IPMSI message and BGP-VNAD-SPMSI message This five attributes are described respectively：

MP_REACH_NLRI attributes

BGP-VNAD-IPMSI message and BGP-VNAD-SPMSI message The form of MP_REACH_NLRI attributes is different.

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

The address family that the MP_REACH_NLRI attributes of BGP-VNAD-IPMSI message are used Identifier (AFI) and subaddressing race identifier (SAFI) and RFC 6074 (and RFC 7117 In to find/bind automatically comprising formula operator multicast tree) used in Address-Family Identifier Accord with (AFI) and subaddressing race identifier (SAFI) is identical, i.e. AFI=25 (L2VPN), SAFI=65 (VPLS).However, the coded format of NLRI fields therein but with RFC Coded format used in 6074 is different.In addition to VN has found automatically, the NLRI VN context IDs (VN Context ID) are also indicated by signaling.

It should be noted that the NLRI of this form is initially defined on the title of same inventor For the first hair of " a kind of distributed couple in multiplexer DAM stacking networks system and its apparatus " In bright patent application.In embodiment of the disclosure, in the BGP-VNAD-IPMSI newly defined NLRI this form has been reused in message.

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

The MP_REACH_NLRI attributes of BGP-VNAD-SPMSI message have been reused in RFC Being directed to for defined " finds to route MCAST-NLRI " automatically to S-PMSI in 7117 (that is, AFI=25 (L2VPN), SAFI=8 (MCAST-VPLS), route-type= 3 (S-PMSI find automatically route)) same format that is encoded.Detail refer to RFC 7117。

PMSI_TUNNEL attributes

The initial coded format of PMSI_TUNNEL attributes defined in RFC 6514, and And it is reused in RFC 7117.Similar to RFC 7117, the reality of the disclosure Example is applied the attribute is reused to carry PMSI tunnel informations.Figure 5 illustrates The coded format of PMSI_TUNNEL attributes, the coded format is replicated from RFC 6514 And carried out less modification.

Alternatively, the mark included in above-mentioned amended PMSI_TUNNEL attributes is passed through Field, tunnel type field, the tunnel mark of VN context ID fields and variable-length Symbol field is known, to carry the PMSI tunnel informations.

As described above, replicating the coding lattice of PMSI_TUNNEL attributes from RFC 6514 Formula has simultaneously carried out less modification, for example, " VN context IDs " field in Fig. 5 exists Initially it is named as in RFC 6514 " MPLS label ".However, in Figure 5, by the word Section is referred to as " VN context IDs ", to represent the PMSI_TUNNEL in embodiment of the disclosure Attribute is used to carry the information that point-to-multipoint NVO3 is superimposed tunnel, rather than for carrying IETF L2VPN/L3VPN multicast informations based on MPLS.

In the initially PMSI_TUNNEL attributes as defined in RFC 6514, by 38 " MPLS label " field of bit byte limits only to carry the value of 20 bits, in the disclosure Embodiment in eliminate this limitation, so as to allow it to carry 24 bit values or 20 bits Any one of value.In embodiment of the disclosure, according to NVO3 superposition tunnel-like Type, " VN context IDs " field of 3 octets can be carried for VXLAN's Being superimposed the VXLAN network identifiers (VNI) of 24 bits in tunnel or carrying is used for The virtual subnet identifier (VSID) of 24 bits in NVGRE superpositions tunnel carries use In the MPLS service labels of 20 bits in the superposition tunnel that MPLS is encapsulated in GRE. As " VN context IDs " code field MPLS of 20 bits of this 3 octets During service label, only using only 20 high-order bits, and remain 4 bits of low level and answer This is set to zero, this with RFC 6514 defined it is consistent.

For " tunnel type (Tunnel Type) " field in Fig. 5, RFC 7117 by its In value limit only to be one in 0,1,2 or 6, these values are corresponded respectively to " no There is tunnel information ", " RSVP-TE P2MP LSP ", " LDP P2MP LSP " and " enter Mouth is replicated ".That is, RFC 7117 does not support any based on IP and compatibility NVO3 PMSI tunnels.In order to support the PMSI tunnel types based on IP and compatibility NVO3, this Disclosed embodiment allows " tunnel type " value in PMSI_TUNNEL attributes to be set For 3 (PIM-SSM trees) or 4 (PIM-SM trees).Therefore, alternatively, the tunnel Type field is arranged to support to set up the multicast tree of the Protocol Independent Multicast in designated multicast source. Also, alternatively, the tunnel type field is arranged to support the association for setting up sparse mode Discuss the multicast tree of independent multicast.

Although it should be noted that defined in interconnection network data distributor gear (IANA) PMSI tunnel types 3 and 4, but be but specifically defined as being used in RFC 6514 The BGP codings of BGP/MPLS IP-VPN multicasts.In other words, if without such as originally If appropriate extension disclosed in text, then its by can not be with VPLS multicasts L2VPN NLRI (AFI=25, SAFI=65 or 8), which is combined, to be used.Embodiment of the disclosure Allow PMSI tunnel types 3 (PIM-SSM trees) and type 4 (PIM-SM trees) and L2VPN NLRI, which is combined, to be used, and describes these new PMSI tunnel types and L2VPN NLRI is combined the appropriate ways used.

As described above, because RFC 7117 only support using MPLS service labels as based on In MPLS polymerization operator multicast tree (that is, RSVP-TE or mLDP P2MP LSP) Demultiplexing symbol, so in RFC 7117 be used only PMSI_TUNNEL attributes in one It is sufficient that individual tunnel type field is to specify operator's multicast tree.However, in DAM institute In the superposition of the point-to-multipoint based on the IP and compatibility NVO3 tunnel used, use A tunnel type field in PMSI_TUNNEL attributes is not enough to specify leaf node to tunnel The multicast service worn decapsulated required for institute's necessary information.Except specifying operation Outside business outside multicast tree type (for example, PIM-SSM trees or PIM-SM trees), also need Leaf node is specified to be decapsulated to received packet and recover original BUM Frame or the inside VN encapsulated types of user multicast packet.This is encapsulated by the BGP newly introduced Extended community attribute is realized.It is specific to obtain with reference to BGP encapsulation extended communitys hereinafter Details.

L2VPN identifier extensions group

As described in RFC 6074 and RFC 7117, also provided in bgp update message L2VPN identifier extensions group, its meaning, using and coded format and RFC 6074 in Defined it is identical.In DAM models, these L2VPN identifier extensions groups indicate Corresponding to corresponding BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message L2VPN examples, therefore, it can be envisioned for the specific VN in each DAM modules Example (for example, IP operation example or L2VPN srvice instance as described in figure 2) It is identified.This value must be locally configured in the network virtual entity of each DAM modules On.Any one of two kinds of canonical forms of the defined such as in RFC 6074 can be used Canonical form is encoded to L2VPN identifier extensions group.

If it should be noted that VN context IDs represent respectively VXLAN or NVGER The VN identifiers of the global senses such as VNI or VSID in network, then in L2VPN marks Know between the value of symbol and the value of VN context IDs and there will be man-to-man mapping, although L2VPN identifiers and VN context IDs have different field length, but they are all unique Ground identifies VN examples.

BGP encapsulates extended community

In existing VPLS multicasts (RFC 7117) and BGP-AD (RFC 6074) times BGP is all not present in what bgp update message and encapsulates extended community.RFC 7117 and RFC 6074 can not all indicate the tunnel type of BGP tunnel encapsulations by signaling.That is, In RFC 7117, VN context IDs are the MPLS service labels of local sense all the time.BGP Encapsulation extended community is initially defined in RFC 5512, and it, which is that BGP is opaque, expands Exhibit-delegation's body (type is 0x030c), to indicate tunnel used in the encapsulation of tunnelling frame/packet Road type.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, Alternatively, the BGP encapsulation extended community attribute is arranged to support virtual expansible local Net.Alternatively, the BGP encapsulation extended community attribute is arranged to support to use general road By the network virtualization encapsulated.Also, alternatively, the BGP encapsulation extended community attribute It is arranged to support to encapsulate multiprotocol label switching in generic route encapsulation.

In brief, " BGP encapsulates extended community " is combined in PMSI_TUNNEL attributes " tunnel type " field, uniquely specifies following content：(1) IP and compatibility NVO3 are based on Operator's multicast tree (one kind in PIM-SSM trees or PIM-SM trees)；And, (2) (VXLAN, NVGRE are encapsulated the encapsulated type in NVO3 superpositions tunnel in GRE One kind in MPLS).

It should be noted that up to the present only having VXLAN, NVGRE or in GRE Middle encapsulation MPLS is suitable to DAM and is superimposed tunnel.IETF NVO3 working groups are currently right New tunnel type is studied.If IETF receives any new tunnel type, then Embodiment of the disclosure easily can encapsulate extended community to extend by using BGP Other new NVO3 are superimposed with the support of tunnel type.

Route target extended community

Used in route target (RT) extended community and RFC 7117 and/or RFC 6074 Route target (RT) extended community it is identical.It is the bgp update message in many applications In the standard extension group that all occurs；Its meaning, using and coded format and RFC 6074 in Defined it is identical.It is not described in detail in embodiment of the disclosure.

, can also be suitably by other BGP in addition to above-mentioned five crucial bgp attributes Attribute is added in bgp update message.Embodiment of the disclosure does not list these attributes, Because these attributes are found and I-PMSI/S-PMSI signalings automatically with the VN in DAM models It is unrelated.

In DAM models, 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 build During vertical point-to-point NVO3 L2 superpositions tunnel；And

(2) I-PMSI tunnel informations are indicated to RAM by signaling, to set up a little pair During multiple spot I-PMSI tunnels；

ERM should declare the bgp update message (BGP on the right side of Fig. 3 as illustrated in fig. 3 New information).In embodiment of the disclosure, the bgp update message of this form is claimed Make BGP-VNAD-IPMSI message, it supports VN simultaneously in a bgp update message It is automatic to find signaling and I-PMSI signalings.

It should be noted that when RAM (or is not added to the CPM of any operator's multicast tree Or SPM) need its VN member relation being indicated to other DAM modules by signaling, So as to set up during point-to-point NVO3 L2 superpositions tunnel (that is, VN has found automatically), it should Bgp update message (with grey represented) of the declaration as shown in Fig. 3 left side.This lattice A kind of entitled " distributed couple in multiplexer of the bgp update message of formula in same inventor It is defined in the first application for a patent for invention of DAM stacking networks system and its apparatus ", No longer it is described in detail in embodiment of the disclosure.In embodiment of the disclosure, The bgp update message of this form will be referred to as BGP-VNAD-ONLY message.

Similarly, in the DAM models, when ERM needs to lead to S-PMSI tunnel informations Cross signaling and be indicated to RAM, to set up during point-to-multipoint S-PMSI tunnels, ERM should Declare bgp update message as illustrated in fig. 4.In embodiment of the disclosure, this BGP New information is referred to as BGP-VNAD-SPMSI message.

It should be noted that S-PMSI tunnels are used to transmit specific user multicast stream, this A little specific user multicast streams are usually specific user's multicast stream of high data volume and set up.Tool Body details refer to RFC 7117.

The process for setting up these PMSI tunnels is similar with the process of defined in RFC 7117, But following modification has been carried out to RFC 7117：

(1) support PMSI tunnel types 3 and type 4 are expanded to, so that PIM-SSM trees and/or PIM-SM trees can be set up as including formula/selecting type operator group Broadcast tree.

(2) form of bgp update message is modified.In bgp update message The new BGP encapsulation extended community of addition is (initially defined in RFC 5512, but at this It is reused in disclosed embodiment), to indicate that BGP used in the encapsulation of traffic frame is encapsulated Tunnel type.In embodiment of the disclosure, BGP encapsulation tunnels type 8,9,11 is supported, It 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 therein The value of (Tunnel Type) " fields limits only to be one in 0,1,2 or 6, this A little 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 foundation and is based on MPLS operator's multicast tree (RSVP-TE or mLDP P2MP LSP).So needing RFC 7117 is extended, IP and compatibility NVO3 are based on to be set up between DAM modules Operator's multicast tree.

Following pseudo Algorithm shows how MP-BGP processing routines can extend to support base In IP and compatibility NVO3 I-PMSI tunnels and S-PMSI tunnels.

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

NVO3 is point-to-point and/or the topology in point-to-multipoint superposition tunnel by BGP-VNAD-ONLY message, BGP-VNAD-IPMSI message and Route target extended community (also referred to as exporting RT) in BGP-VNAD-SPMSI message With the input route target (input configured for each VN examples in DAM modules RT) it is controlled.Embodiment of the disclosure does not elaborate the mechanism of this standard.When Combination of the output RT values with inputting RT values allow BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message is imported into a DAM module (that is, leaf node) When in VN examples, following message can be therefrom extracted：

(1) type (PIM-SSM of operator's multicast tree based on IP and compatibility NVO3 One kind in tree or PIM-SM trees)

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

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

(4) BUM flows or user multicast flow from operator's multicast tree are demultiplexed VN context IDs value (it should be noted that：If context ID=0, run Business's multicast tree is non-polymeric)

(5) in the case of S-PMSI message, user multicast stream (by user's multicast source Location and group IP address are identified) it is tied to selecting type operator multicast tree

Carried out into BGP-VNAD-IPMSI message or BGP-VNAD-SPMSI message After work(decoding, DAM modules should be by sending IGMP (IGMP) Message is added to add PIM-SSM or PIM-SM trees immediately, and preparation is from being set up Comprising formula or selecting type operator multicast tree receive (alternatively being demultiplexed) BUM flow or User multicast stream.It is not described in detail for embodiment of the disclosure.

Fig. 6 shows the equipment 600 in DAM systems in accordance with an embodiment of the present disclosure.If Standby 600 include processing unit 601, and processing unit 601 is as described above in DAM to perform The various methods of operator's multicast tree are set up in system.

Alternatively, processing unit 601 to transmit BGP message BGP-VNAD-IPMSI or At least one of BGP-VNAD-SPMSI, to set up operator's multicast tree；It is wherein described BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message packages contain with subordinate Property：MP_REACH_NLRI attributes, PMSI_TUNNEL attributes and BGP encapsulation Extended community attribute.

Alternatively, processing unit 601 is by the MP_REACH_NLRI attributes, to send out Cloth transmits the void under VN examples up to the purpose network information and corresponding next hop information Intend network context identifier ID；PMSI is carried by the PMSI_TUNNEL attributes Tunnel information；And, encapsulate extended community attribute to indicate stacking network by the BGP The tunnel type of tunnel encapsulation.

Alternatively, processing unit 601 is transmitted the BGP-VNAD-IPMSI message and The BGP-VNAD-SPMSI message also comprising L2VPN identifier extensions group attribute and Route target extended community attribute.

Alternatively, processing unit 601 by the L2VPN identifier extensions group attribute come Identify the specific virtual network example in the DAM systems；And, pass through the route mesh Extended community attribute is marked to control the topological structure in stacking network tunnel.

In summary, the following machine for DAM models has been proposed in embodiment of the disclosure System.

Two kinds of new bgp update message formats are proposed, are claimed in embodiment of the disclosure Make BGP-VAND-IPMSI message and BGP-VNAD-SPMSI message, by the DAM The root node (that is, ERM) of operator's multicast tree in model declares both message, uses In bgp update message carry out VN find automatically and I-PMSI signaling indicate or Indicated to the S-PMSI signalings in bgp update message.Proposed BGP-VAND-IPMSI message and BGP-VNAD-SPMSI message can be with same inventions A kind of first application for a patent for invention (entitled " distributed couple in multiplexer DAM superpositions of people Network system and its device ") proposed in BGP-VNAD-ONLY message coexist, institute BGP-VNAD-ONLY message is stated by being added without the leaf node in operator's multicast tree (i.e., RAM, CPM, SPM) declared.

Briefly carry BUM business and user's group to how to be set up in DAM models Broadcast being described comprising formula/selecting type operator multicast tree for business.However, it is desirable to understand , embodiment of the disclosure scope of the claimed is only defined by the subject-matter of the claims.

Claims

1. a kind of set up operator's multicast tree in distributed couple in multiplexer DAM systems Method, including：

Border Gateway Protocol (BGP) is transmitted between NE in the DAM systems to disappear At least one of BGP-VNAD-IPMSI or BGP-VNAD-SPMSI are ceased, to build Found operator's multicast tree；

Wherein described BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI disappear Breath is included with properties：

MP_REACH_NLRI attributes, PMSI_TUNNEL attributes and BGP encapsulation Extended community attribute.

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

By the MP_REACH_NLRI attributes, issuing up to the purpose network information and Corresponding next hop information, and transmit the virtual network context under virtual network VN examples Identifier ID；

Operator's multicast services interface is carried by the PMSI_TUNNEL attributes PMSI tunnel informations；And

Encapsulate extended community attribute to indicate the tunnel of stacking network tunnel encapsulation by the BGP Road type.

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

, will when the BGP-VNAD-IPMSI message is transmitted between the NE VN context ID fields are included in the MP_REACH_NLRI attributes, to distinguish Different VN contexts.

4. method according to claim 3, wherein：

Pass through the attribute field included in the PMSI_TUNNEL attributes, tunnel type The tunnel identifier field of field, VN context ID fields and variable-length, to take With the PMSI tunnel informations.

5. method according to claim 4, wherein：

The tunnel type field is arranged to support the agreement independence group for setting up designated multicast source The multicast tree broadcast.

6. method according to claim 4, wherein：

The tunnel type field is arranged to support the agreement for setting up sparse mode independent The multicast tree of multicast.

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

The BGP encapsulation extended community attribute is arranged to support virtual expansible LAN.

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

The BGP encapsulation extended community attribute is arranged to support using generic route encapsulation Network virtualization.

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

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

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

The BGP-VNAD-IPMSI message and the BGP-VNAD-SPMSI message are also Include the Virtual Private Network L2VPN identifier extensions group attribute of layer 2 and route target extension group Body attribute.

11. method according to claim 10, wherein：

Identified by the L2VPN identifier extensions group attribute in the DAM systems Specific virtual network example；And

The topology knot in stacking network tunnel is controlled by the route target extended community attribute Structure.

12. a kind of set up operator's multicast tree in distributed couple in multiplexer DAM systems Equipment, including：

Processing unit, for transmitting border net between the NE in the DAM systems Close in agreement BGP message BGP-VNAD-IPMSI or BGP-VNAD-SPMSI at least One kind, to set up operator's multicast tree；

13. equipment according to claim 12, wherein：

The processing unit is by the MP_REACH_NLRI attributes, to issue up to mesh The network information and corresponding next hop information, and transmit the void under virtual network VN examples Intend network context identifier ID；Operation is carried by the PMSI_TUNNEL attributes Business's multicast services interface PMSI tunnel informations；And extended community is encapsulated by the BGP Attribute indicates the tunnel type of stacking network tunnel encapsulation.

14. equipment according to claim 12, wherein：

The BGP-VNAD-IPMSI is transmitted between the devices when the processing unit to disappear During breath, VN context ID fields are included in the MP_REACH_NLRI attributes, The VN context different to distinguish.

15. equipment according to claim 14, wherein：

16. equipment according to claim 15, wherein：

17. equipment according to claim 15, wherein：

The tunnel type field is arranged to support the Protocol Independent Multicast for setting up sparse mode Multicast tree.

18. the equipment according to any one of claim 16-17, wherein：

19. the equipment according to any one of claim 16-17, wherein：

20. the equipment according to any one of claim 16-17, wherein：

21. equipment according to claim 12, wherein：

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

22. equipment according to claim 21, wherein：

The processing unit is identified described by the L2VPN identifier extensions group attribute Specific virtual network example in DAM systems；And pass through the route target extended community Attribute controls the topological structure in stacking network tunnel.