CN100484078C - A method to realize VPN multicast - Google Patents

Abstract

The related method for realizing VPN multicast comprises: VPN network calculates the coverage degree of current multicast member, and decides whether the coverage value less than a given threshold; yes to build a public network multicast distribution tree (P-Tree) with coverage value not less than the threshold. This invention reduces waste of bandwidth.

Description

A kind of method that realizes the VPN multicast

Technical field

The present invention relates to a kind of method of multicasting, particularly a kind of method that in multicast domain, realizes the VPN multicast.Belong to the communications field.

Background technology

In the network, each user access point is called a website (Site).Comprise following entity in VPN (Virtual Private Network) network: operator edge router (Provider Edge Router, be called for short PE) be used for providing network interface, storing virtual route (VirtualRouting Forwarding Instance for the user in provider backbone, be called for short VRF) transmit, handle the VPN-IPv4 route, insert the VPN subnet that is positioned at each website, be the main realization part of VPN; User's border router (Customer Edge Router, be called for short CE), the network interface of access carrier backbone network in the user VPN website converges the VPN route of this website, issue and receive the user network route; Carrier network core router (being called for short the P router) is being born the task that all packets are transmitted in backbone network; The VPN user of each website connects local operator edge router PE through user's border router CE, and on PE the virtual route VRF of corresponding specific memory.Last some strategies of configuration of VRF stipulate that the router of this website can receive the routing iinformation of which website, can outwards issue those routing iinformations.Each PE carries out route according to the extend information of BGP (Border Gateway Protocol) and calculates, and generates the routing table of each relevant VPN.The a plurality of routing tables of operator edge router PE plant maintenance, many examples of support dynamic routing protocol.

Carrier network is the public network network that is used to transmit the multicast packet of different websites.Wherein, comprise public network multicast group (being called for short P-Group), public network multicast issuing tree (being called for short P-Tree).

User's private network be one independently, autonomous IPv4 network system.Wherein, comprise private network multicast group (being called for short C-Group), private network multicast distribution tree (being called for short C-Tree).

Multicasting VPN scheme is in a variety of forms realized, is the full annexation of setting up multicast between all CE of user VPN network as unicast scheme (being called for short GRE Tunnel), finishes point-to-point tunnel and connects.This scheme exists serious efficiency, one of them CE of every change, and other are all all needs to reconfigure, so the scalability of system is very poor.

Multicast domain scheme (Multicast-Domain is called for short MD) is by setting up for each VPN in existing carrier network and safeguarding that a multicast domain realizes.It comes down to a multiport tunnel, each pe router all is a port in this tunnel, the data that enter from any port all can flow out at other port beyond this port, so the user can simply regard this multicast domain as a network switch (LAN Switch).In this scheme, multicast packet adopts the mode of inundation to transmit in backbone network multicast domain router, data forwarding is not optimum the forwarding, can arrive the router that does not have the private network recipient, be dropped then, this has wasted the network bandwidth in the backbone network to a certain extent, has also increased the processing load of router.

Multicast domain (MD) improvement project, when certain the multicast group data transmission quantity of certain VPN in the multicast domain surpasses certain threshold value, adopt VPN-IP PIM scheme to set up a dynamic multicast distribution tree (Multicast Distribution Tree for this multicast group, be called for short MDT), flux of multicast can be optimized path flow along this dynamic MDT.Can reduce like this multicast path in the operator management public network by burden, also provide guarantee simultaneously for muticast data transmission at a high speed.In fact, this scheme of setting up dynamic MDT for VPN still exists certain limitation, because in operation, need in the network VPN number supported a lot, and a lot of dynamically MDT arranged again among each VPN, thus when adopting improved multicast domain method in the public network multicast routing table item still a lot; Simultaneously, in the middle of this scheme, can only detect the big situation of flow in the public network multicast group, can not good treatment and website is distributed the sparse shortcoming that causes.

In existing VPN multicast scheme, improved multicast domain scheme is the detection of adopting flow, and its route table items is controlled fully, and the advantage that can be optimized transmission simultaneously again at specific data source has obtained the approval of most researchers.But improved multicast domain scheme has only been considered the high problem of certain source transmission rate, and does not consider the sparse problem of website distribution, and bandwidth waste at this moment still is very large.

Summary of the invention

Technical problem to be solved by this invention is at deficiency of the prior art, a kind of method that realizes the VPN multicast in multicast domain is provided, this method is considered the member's sparse situation that distributes that receives, at this situation, introduced the notion that coverage detects, size according to coverage is determined P-Tree, has reduced the waste of bandwidth.

For this reason, the invention provides a kind of method that in multicast domain, realizes the VPN multicast, comprise the steps:

Group management router in step 11, the described VPN network side periodically sends the coverage query messages in multicast domain, be used to inquire about current recipient PEs tabulation;

Receive among step 12, the VPN that the router of query messages determines to send described group of management router of described query messages;

Step 13, receive that the router of query messages judges the type of described query messages, if inquire about all groups, then execution in step 14; If the query portion group, then execution in step 17;

Step 14, the router of receiving query messages all are sent back to described group of management router to the multicast group address that belongs to described group of management router management in its route forwarding table;

Step 15, described group of management router are collected described response message, draw the reception member tabulation of the group of being inquired about through statistics;

Step 16, described group of management router analytic statistics result calculate the coverage of current each group, according to following formula:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router, and C-Group is the private network multicast group, and P-Tree is a public network multicast issuing tree; Execution in step 2 then;

Step 17, the router of receiving query messages are confirmed the group that will inquire about if oneself be connected with the reception member of this group, then this group address to be sent back to described group of management router; Execution in step 15 then;

Step 2, VPN network side judge that whether the numerical value of this coverage is less than predefined coverage threshold value, if then execution in step 3; If not, then finish;

Step 3, VPN network side are set up a public network multicast issuing tree, receive in the current multicast group member for the coverage of described public network multicast issuing tree more than or equal to predefined coverage threshold value.

The present invention is directed to improved MD scheme, the notion of a new coverage has been proposed, detection by coverage, reduced the sparse bandwidth waste that causes of butt joint harvest person website distribution in the prior art, under the situation that coverage does not satisfy condition, by the method for a selection or a newly-built P-Tree, the feasible requirement of satisfying coverage, just avoid receiving the sparse situation of member's website distribution, reduced the waste of bandwidth.

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

Description of drawings

Fig. 1 is the flow chart of first embodiment of the invention;

Fig. 2 is the particular flow sheet of step 1 in the first embodiment of the invention;

Fig. 3 is the particular flow sheet of step 3 in the first embodiment of the invention;

Fig. 4 is the flow chart of a preferred embodiment of the present invention.

Embodiment

At first introduce relational language involved in the present invention below.

Group management router: for managing with maintenance work and being used to finish the router of mapping function.The group management router is with respect to each C-Group.As, switch to the private network multicast group (C-Group) in the public network, need select the distribution tree of a public network multicast issuing tree (P-Tree) for it as it.The group management router is exactly supervision and management C-Group, and for it sets up distribution tree P-Tree, and other recipient's operator edge router PE of notice C-Group switches on this P-Tree.A router entity may comprise a lot of group management router, and these group management router can be shared the distribution tree of this router, perhaps to the newly-built distribution tree of this router solicitation.We also represent that with the group management router comprises a router entity of organizing management router.In practice, the group management router can be born by other functional entity, for example, and pe router.

Coverage: be meant that C-Group is to the level of coverage of P-Tree when recipient PE member when private network multicast group (C-Group) is the PE member of P-Tree (that is to say that both are relations of subclass and former collection).Its value is a real number value between [0,1].If adopt certain P-Tree to distribute the packet of this C-Group, coverage is more little, represents that then the bandwidth waste degree is big more.Its formula is as follows:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router; C-Group is the private network multicast group; P-Tree is a public network multicast issuing tree.

Multicast domain: be one the distribution tree that each VPN disposed, it is a static shared tree, has comprised all PE members of VPN, and all C-Group acquiescences are used this tree distributing data, and the control messages of some VPN is also distributed in this tree.

Embodiment 1

Fig. 1 is the flow chart of first embodiment of the invention.As shown in Figure 1, the present invention includes following steps:

Group management router in step 1, the VPN network side is periodically inquired about current recipient PEs tabulation, and the VPN network side calculates the coverage that receives the member in the current multicast group according to following formula:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router; C-Group is the private network multicast group; P-Tree is a public network multicast issuing tree;

Step 2, VPN network side judge that whether the numerical value of this coverage is less than predefined coverage threshold value, if then execution in step 3; If not, then finish;

Step 3, VPN network side are set up a public network multicast issuing tree, receive in the current multicast group member for the coverage of described public network multicast issuing tree more than or equal to predefined coverage threshold value.

All receive members' public network multicast issuing tree to step 3 in order to select for use an existing energy to cover current multicast group, and described current multicast group all receive members for the coverage of this public network multicast group distribution tree more than or equal to the coverage threshold value, perhaps all receive newly-built one of members and can cover current multicast group all receive members' public network multicast issuing tree for current multicast group, and described current multicast group all receive members for the coverage of newly-built public network multicast group distribution tree more than or equal to the coverage threshold value.

Embodiment 2

Fig. 2 is the particular flow sheet of step 1 in the first embodiment of the invention.The difference of present embodiment and embodiment 1 only is that with the concrete refinement of the step 1 among the embodiment 1, all the other steps are with embodiment 1.As shown in Figure 2, step 1 is specially:

Group management router in step 11, the described VPN network side periodically sends the coverage query messages in multicast domain, be used to inquire about current recipient PEs tabulation;

Receive among step 12, the VPN that the router of query messages determines to send described group of management router of described query messages;

Step 13, receive that the router of query messages judges the type of described query messages, if inquire about all groups, then execution in step 14; If the query portion group, then execution in step 17;

Step 14, the router of receiving query messages all are sent back to described group of management router to the multicast group address that belongs to described group of management router management in its route forwarding table;

Step 15, described group of management router are collected described response message, draw the reception member tabulation of the group of being inquired about through statistics;

Step 16, described group of management router analytic statistics result calculate the coverage of current each group, according to following formula:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router, and C-Group is the private network multicast group, and P-Tree is a public network multicast issuing tree; Finish then;

Step 17, the router of receiving query messages are confirmed the group that will inquire about if oneself be connected with the reception member of this group, then this group address to be sent back to described group of management router; Execution in step 15 then.

Embodiment 3

Fig. 3 is the particular flow sheet of step 3 in the first embodiment of the invention.The difference of present embodiment and embodiment 1 only is step 3 is carried out concrete refinement, and as shown in Figure 3, the concrete steps of step 3 are:

Among step 31, the existing P-Tree of VPN network side, whether the P-Tree that can cover the described reception of current multicast group member is arranged, and receive in the described current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value, if then execution in step 32; If not, execution in step 33 then;

Step 32, select an existing P-Tree distributing information, and the described reception of current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value; Finish then;

Step 33, for all receive newly-built one of members and can cover current multicast group all receive members' P-Tree in the current multicast group, and described current multicast group all receive members for the coverage of newly-built P-Tree more than or equal to the coverage threshold value.

Embodiment 4

Fig. 4 is the flow chart of a preferred embodiment of the present invention.As shown in Figure 4, the present invention includes following steps:

Group management router in step 11, the described VPN network side periodically sends the coverage query messages in multicast domain, be used to inquire about current recipient PEs tabulation;

Receive among step 12, the VPN that the router of query messages determines to send described group of management router of described query messages;

Step 13, receive that the router of query messages judges the type of described query messages, if inquire about all groups, then execution in step 14; If the query portion group, then execution in step 17;

Step 14, the router of receiving query messages all are sent back to described group of management router to the multicast group address that belongs to described group of management router management in its route forwarding table;

Step 15, described group of management router are collected described response message, draw the reception member tabulation of the group of being inquired about through statistics;

Step 16, described group of management router analytic statistics result calculate the coverage of current each group, according to following formula:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router, and C-Group is the private network multicast group, and P-Tree is a public network multicast issuing tree; Finish then;

Step 17, the router of receiving query messages are confirmed the group that will inquire about if oneself be connected with the reception member of this group, then this group address to be sent back to described group of management router, and execution in step 15 then;

Step 2, VPN network side judge that whether this coverage is less than predefined coverage threshold value, if then execution in step 3; If not, then finish;

Among step 31, the existing P-Tree of VPN network side, whether the P-Tree that can cover the described reception of current multicast group member is arranged, and receive in the described current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value, if then execution in step 32; If not, execution in step 33 then;

Step 32, select an existing P-Tree distributing information, and the described reception of current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value; Finish then;

Step 33, can cover current multicast group all receive members' P-Tree for receiving newly-built one of member described in the current multicast group, and described current multicast group all receive members for the coverage of newly-built P-Tree more than or equal to the coverage threshold value.

It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not break away from the spirit and scope of technical solution of the present invention.

Claims (3)

1. a method that realizes the VPN multicast in multicast domain is characterized in that, comprises the steps:

Group management router in step 11, the VPN network side periodically sends the coverage query messages in multicast domain, be used to inquire about current recipient PEs tabulation;

Receive among step 12, the VPN that the router of query messages determines to send described group of management router of described query messages;

Step 13, receive that the router of query messages judges the type of described query messages, if inquire about all groups, then execution in step 14; If the query portion group, then execution in step 17;

Step 14, the router of receiving query messages all are sent back to described group of management router to the multicast group address that belongs to described group of management router management in its route forwarding table;

Step 15, described group of management router are collected described response message, draw the reception member tabulation of the group of being inquired about through statistics;

Step 16, described group of management router analytic statistics result calculate the coverage of current each group, according to following formula:

$\mathrm{PEs}(C-\mathrm{Group})\⊆(P-\mathrm{Tree})$

Wherein, PEs is the operator edge router, and C-Group is the private network multicast group, and P-Tree is a public network multicast issuing tree; Execution in step 2 then;

Step 17, the router of receiving query messages are confirmed the group that will inquire about if oneself be connected with the reception member of this group, then this group address to be sent back to described group of management router; Execution in step 15 then;

Step 2, VPN network side judge that whether the numerical value of this coverage is less than predefined coverage threshold value, if then execution in step 3; If not, then finish;

Step 3, VPN network side are set up a public network multicast issuing tree, and receive in the current multicast group member for the coverage of described public network multicast issuing tree more than or equal to predefined coverage threshold value.

2. the method that in multicast domain, realizes the VPN multicast according to claim 1, it is characterized in that, all receive members' public network multicast issuing tree to described step 3 in order to select for use an existing energy to cover current multicast group, and described current multicast group all receive members for the coverage of this public network multicast group distribution tree more than or equal to the coverage threshold value, perhaps all receive newly-built one of members and can cover current multicast group all receive members' public network multicast issuing tree for current multicast group, and described current multicast group all receive members for the coverage of newly-built public network multicast group distribution tree more than or equal to the coverage threshold value.

3. the method that realizes the VPN multicast in multicast domain according to claim 1 is characterized in that described step 3 is specially:

Among step 31, the existing P-Tree of VPN network side, whether the P-Tree that can cover the described reception of current multicast group member is arranged, and receive in the described current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value, if then execution in step 32; If not, execution in step 33 then;

Step 32, select an existing P-Tree distributing information, and the described reception of current multicast group member for the coverage of this P-Tree more than or equal to the coverage threshold value; Finish then;

Step 33, can cover current multicast group all receive members' P-Tree for receiving newly-built one of member described in the current multicast group, and described current multicast group all receive members for the coverage of newly-built P-Tree more than or equal to the coverage threshold value.

Images