CN102143026B

CN102143026B - Method for avoiding loop circuit in virtual two layer network

Info

Publication number: CN102143026B
Application number: CN201110111731.XA
Authority: CN
Inventors: 宋小恒; 郑国良; 彭剑远
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: New H3C Information Technologies Co Ltd
Priority date: 2011-04-29
Filing date: 2011-04-29
Publication date: 2014-03-12
Anticipated expiration: 2031-04-29
Also published as: CN102143026A

Abstract

The invention provides a method for avoiding a loop circuit in a virtual layer 2 network, which comprises the following steps of: enabling a multiple spanning tree protocol (MSTP) in a virtual switch instance (VSI) of network equipment of the virtual layer 2 network, and binding the VSI with an MSTP instance; and transmitting a bridge protocol data unit (BPDU) message for loop circuit detection by using the MSTP instance. By the method, redundant connection can be pruned in the virtual layer 2 network, and the loop circuit is removed.

Description

A kind of method of avoiding loop in virtual double layer network

Technical field

The present invention relates to virtual double layer network technology, particularly a kind of method of avoiding loop in virtual double layer network.

Background technology

STP (Spanning Tree Protocol, Spanning-Tree Protocol) is the 802.1D normalization formulated according to IEEE association, for eliminate the agreement of data link layer physics loop at local area network (LAN).The equipment that moves this agreement is by the loop in interactive information discovering network each other, and selectively certain port is blocked, loop network structure is trimmed to loop-free tree network structure the most at last, thereby prevent message constantly hyperplasia and Infinite Cyclic in loop network, avoid equipment to occur owing to repeating to receive the problem that message processing capability that identical message causes declines.

MSTP (Multiple Spanning Tree Protocol; Multiple Spanning Tree Protocol) the 802.1s standard definition of being formulated by IEEE; it can make up the defect of STP and RSTP; both can Fast Convergent; the flow that can make again different VLAN forwards along path separately, thereby provides better load balancing mechanism for redundant link.The main feature of MSTP is as follows:

1) MSTP arranges VLAN mapping table (that is: the mapping table of VLAN and spanning tree), and VLAN and spanning tree are connected.By increasing this concept of " example " (a plurality of VLAN are incorporated in a set), a plurality of VLAN can be bundled in an example, to save communication overhead and resources occupation rate.

2) MSTP is divided into a plurality of territories by a switching network, forms many spanning trees in each territory, independent of one another between spanning tree.

3) MSTP prunes loop network to become an acyclic tree network, avoids hyperplasia and the Infinite Cyclic of message in loop network, and a plurality of redundant paths of data retransmission are also provided simultaneously, realizes the load balancing of vlan data in data forwarding process.

At present, MSTP is widely used in double layer network, for detection of and block the physics loop that may occur in double layer network, prevent broadcasting packet Infinite Cyclic in double layer network.Yet existing MSTP only applies to, in two layers of switching network, but cannot support for virtual double layer networks such as VPLS or PBB.Here, VPLS (Virtual Private LAN Service, virtual special local area network) is a kind of point-to-multipoint layer 2VPN business providing in common network; PBB (Provider backbone bridge, provider backbone bridge) is the IP MAN that is independent of telecommunications self, and the main MAC in MAC technology that adopts provides point-to-point private line service at present.

In some more common VPLS and the two stack networking application of VPLS/PBB, can only rely on networking mode and increase restriction and avoid loop.

For example: in the layering of VPLS shown in Fig. 1 networking application, UPE1 (UPE:User-facing Provider Edge, near the PE equipment of user's side) respectively with NPE1 (NPE:Network Provider Edge, network core PE equipment), NPE2 sets up active and standby PW (Pseudo Wire, virtual link) connect, for fear of occurring loop, between NPE1 and NPE2, can not set up PW and be connected.Normal condition down-off will forward between UPE1 and NPE1 or between UPE1 and NPE2, and NPE1/NPE2 can only will arrive local UPE to far-end NPE or by the traffic forwarding of far-end NPE from UPE1 traffic forwarding.If set up PW between NPE1 and NPE2, be connected, will produce the such loop traffic of UPE1-NPE1-NPE2-UPE1.Certainly, can on UPE1, the flow from NPE2 be abandoned, but NPE2 sends to the normal message forwarding that the flow of UPE1 will certainly affect UPE1; And, at UPE1 equipment, occur that active and standby PW switches or during switchback, may cause moment loop or packet loss, affect VPLS traffic forwarding quality.Therefore, for fear of this situation, generally by networking mode, evade, between NPE1 and NPE2, do not set up PW and be connected, this causes can not articulating CE (Customer Edge, user network boundary device) under NPE1 and NPE2.

Again for example, in the two stack networking application of VPLS/PBB, all VPLS territory all must be through the two stack equipment switchings in center to the flow in PBB territory.If only have the two stack equipment in Yi Tai center, once two stack device fails in center so, the flow between VPLS territory and PBB territory just cannot forward; But when there is the two stack equipment in Duo Tai center, will inevitably in whole VPLS/PBB territory, produce loop, as shown in Figure 2.

In Fig. 2, PE (Provider Edge, edge device on service provider network) be the edge device in VPLS territory, PE2/BEB2 and PE3/BEB3 are two two stack equipment, BEB1 is the edge device in PBB territory, and the broadcasting packet that PE1 sends will form along PE1-PE2-BEB1-BEB3-PE1 path loop.For fear of forming loop, two stack networkings still only limit to only have the networking of the two stack equipment in Yi Ge center at present, and this networking mode itself exists very large potential safety hazard.

Summary of the invention

The invention provides a kind of method of avoiding loop in virtual double layer network, between connecting with the public network PW annular at virtual double layer network, form effective loop detection, and prune unnecessary connection and remove loop, thereby the networking of the virtual double layer networks such as expansion VPLS/PBB is used.

A kind of method of avoiding loop in virtual double layer network provided by the invention, comprising:

A, in the virtual switch instance VSI of the network equipment of virtual double layer network, enable Multiple Spanning Tree Protocol MSTP, and by VSI example and a MSTP example binding;

B, described MSTP example send Bridge Protocol Data Unit BPDU message and carry out loop detection.

Preferably, the object media access control MAC address of described BPDU message is the particular address setting in advance, and source MAC is for sending the MAC Address of the equipment of described BPDU message.

Preferably, the particular address setting in advance described in is the sign of 01-80-C2-VSI example.

Preferably, described virtual double layer network comprises: the two stack networking networks of virtual special local area network VPLS hierarchical network and VPLS/ provider backbone bridge PBB;

Described VSI example comprises: VPLS example and PBB example.

Preferably, the network equipment of described virtual double layer network is: the edge device PE on service provider network;

The method sends before BPDU message carries out loop detection at MSTP example, further comprises: if a PE has set up main virtual link PW with the 2nd PE, be connected, set up standby PW with the 3rd PE and be connected, and exist PW to be connected between the 2nd PE and the 3rd PE:

The one PE is set to root bridge, and on a PE, MSTP priority is set to the highest; On the 2nd PE equipment, the 2nd PE is connected with PW between a PE and is set to root PW and connects, and the 2nd PE is connected to the connection as appointment PW with the PW between the 3rd PE; On the 3rd PE, the 3rd PE is connected as specifying PW to connect with the PW between the 2nd PE, and the 3rd PE is connected to the connection as blocking-up PW with the PW between a PE.

Preferably, the network equipment of described virtual double layer network is: backbone edge bridge BEB;

The method sends before BPDU message carries out loop detection at MSTP example, further comprises: if a BEB has set up PW with the 2nd BEB with the 3rd BEB respectively, be connected, and exist PW to be connected between the 2nd BEB and the 3rd BEB:

The one BEB is set to root bridge, and on a BEB, MSTP priority is set to the highest; On the 2nd BEB equipment, the 2nd BEB is connected with PW between a BEB and is set to root PW and connects, and the 2nd BEB is connected to the connection as appointment PW with the PW between the 3rd BEB; On the 3rd BEB, the 3rd BEB is connected as specifying PW to connect with the PW between the 2nd BEB, and the 3rd BEB is connected to the connection as blocking-up PW with the PW between a BEB.

After described A, may further include:

In VSI example, be that the described network equipment is specified the opposite end that sends BPDU message;

When receiving BPDU message, the network equipment is that the BPDU message of the particular address that sets in advance transfers to key-course to process by object MAC;

When the BPDU message receiving from local subscriber apparatus side, be used as general data message and process;

When the BPDU message receiving from far-end network equipment side, be used as general data message and process.

After described A, may further include: shine upon as follows:

Port path expense by the path cost of VSI example virtual link PW corresponding to MSTP example;

Bridge sign using the sign of the VSI place network equipment in expansion MSTP territory;

By the outgoing interface of the PW place PW equipment of VSI example corresponding to the common port in MSTP territory.

As seen from the above technical solution, in the VSI example of the method for avoiding loop in virtual double layer network provided by the invention by the network equipment at virtual double layer network, enable MSTP, and by VSI example and a MSTP example binding, thereby, MSTP example can send BPDU message and carry out loop detection in virtual double layer network, and prunes unnecessary connection and remove loop.By the inventive method application and VPLS hierarchical network or the two stack networking networks of VPLS/PBB, can between public network PW annular connects, form effective loop detection, thereby the networking of expansion VPLS/PBB is used.

Accompanying drawing explanation

Fig. 1 avoids the networking mode schematic diagram of loop in existing VPLS layering networking application;

Fig. 2 avoids the networking mode schematic diagram of loop in the two stack networking application of existing VPLS/PBB;

Fig. 3 realizes the schematic diagram of MSTP technology in the two stack networkings of VPLS/PBB layering in one embodiment of the invention;

Fig. 4 is the message repeating schematic diagram in one embodiment of the invention.

Embodiment

For making object of the present invention, technical scheme and advantage clearer, referring to the accompanying drawing embodiment that develops simultaneously, the present invention is described in further detail.

Main thought of the present invention is: in the VSI example by the network equipment at virtual double layer network, enable MSTP, and by VSI example and a MSTP example binding, thereby, MSTP example can send Bridge Protocol Data Unit (BPDU in virtual double layer network, Bridge Protocol Data Unit) message carries out loop detection, and prune unnecessary connection and remove loop, thereby the networking of expansion VPLS/PBB is used.

In the present invention, VSI example comprises VPLS example and PBB example, and the two stack networkings of VPLS layering networking and VPLS/PBB of take are example, and wherein, dual-homed situation and the VPLS layering of the inner CE of VPLS is similar, and the Hierarchical Virtual Private LAN Service of take describes as example, as shown in Figure 3.

PE1 has set up active and standby PW with PE2 and PE3 respectively and has been connected, and sets up VPLS and connect between PE2 and PE3, has set up MAC IN MAC and be connected between BEB4 and PE2, PE3.In above-mentioned networking, having two loops that may occur, is respectively PE1-PE2-PE3-PE1 and BEB4-PE2-PE3-BEB4.For fear of these two loops, can in the VSI of PE equipment example, enable MSTP, and by an example binding of VSI example and MSTP, by MSTP, send specific Bridge Protocol Data Unit (BPDU, Bridge Protocol Data Unit) and carry out loop detection.

For with existing user network in MSTP BPDU message distinguish mutually, need to expand the BPDU message of VSI, enable to carry VSI information can being received by each PE/BEB equipment.Generally, the object MAC of BPDU is 01-80-C2-00-00-00 and 01-80-C2-00-00-08, its object of BPUD message MAC after expansion is 01-80-C2-VSI ID, if VSI ID is 1, corresponding its BPDU message object MAC is 01-80-C2-01-00-00, this target MAC (Media Access Control) address of PE/BEB recognition of devices.The MAC that the source MAC of BPDU message is sending ending equipment, namely sends the MAC Address of the equipment of this BPDU message.

The method that enables MSTP in the VSI of PE1 equipment example is as follows:

Vsi vsi1 static//establishment vsi1 example

The ID of vsi vsi1-id 1 //vsi 1 example

The PW of peer 2.2.2.2enable mstp//be created to PE2 connects and enables MSTP

The PW of peer 3.3.3.3enable mstp//be created to PE2 connects and enables MSTP

The method that enables MSTP in the VSI of BEB4 equipment example is as follows:

Vsi vsi1 i-sid 1//establishment vsi1 example

The PW of peer 2-2-2enable mstp//be created to PE2 connects and enables MSTP

The PW of peer 3-3-3enable mstp//be created to PE3 connects and enables MSTP

VSI example on PE2 and PE3 is the two stack examples of VPLS/PBB, therefore, need to comprise the MSTP configuration of VPLS opposite end and PBB opposite end, enables MSTP method as follows on PE2 equipment:

vsi vsi1 i-sid 1

vsi vsi1-id 1

peer 1.1.1.1 enable mstp

peer 3.3.3.3enable mstp

peer 4-4-4enable mstp

On PE3 equipment, enable MSTP method as follows:

vsi vsi 1i-sid 1

vsi vsi1-id 1

peer 1.1.1.1enable mstp

peer 2.2.2.2enable mstp

peer 4-4-4enable mstp

After above-mentioned processing, in the VPLS example of each PE equipment in Hierarchical Virtual Private LAN Service territory, enabled MSTP, between PE equipment, the BPDU protocol massages of expanding by timed sending is carried out to MSTP loop detection.Compare with common MSTP BPDU message, its object of the BPDU message MAC after expansion is 00-80-C2-VSI ID, the MAC that its source MAC is sending ending equipment, and outer packaging V PLS tunnel header.

In order to realize correct MSTP in VSI territory, detect, need to carry out following setting:

1) in VSI example, for PE equipment, specify to send the opposite end of BPDU message, when PE equipment sends BPDU message, only to the Peer in the VSI example of appointment, send, and can not be to not having Peer opposite end and the local CE side of appointment to send this protocol massages.

2) when receiving BPDU message, the message receiving is a two layer message that carries VPLS label, the object MAC attribute of the BPDU of PE recognition of devices expansion, and forwarding chip, by the upper CPU of message Trap, transfers to the key-course of PE equipment to process.

3) the MSTP BPDU protocol massages entering for local CE side, is used as general data message and processes.

4) the MSTP BPDU protocol massages entering for far-end PE side, is used as general data message and processes.

BPDU message format after expansion is as shown in table 1:

MAC

VPLS label

MAC(00-80-C2-VSI ID)

Transmitting terminal MAC

BPDU Load

Table 1

In table 1, outer MAC is that PE equipment is connected used outgoing interface MAC with other Peer opposite end, VPLS label is that the PW between PE connects label, the object MAC of internal layer MAC is 00-80-C2-VSI ID, according to this extended mode, can support 16M VSI example, meet existing VPLS specification requirement far away.

In order to realize MSTP in VSI territory, detect, the base attribute in VSI and common MSTP territory must be shone upon, specifically comprise the following aspects:

(1) VSI example and MSTP binding, corresponding to the VLAN in common MSTP territory, a plurality of VSI examples can be bound with a MSTP example, the same with a MSTP example binding as a plurality of VLAN;

(2) path cost of VSI PW is corresponding to the port path expense in MSTP;

(3) ID of VSI place PE equipment is as the bridge ID in expansion MSTP territory;

(4) outgoing interface of VSI PW place PW equipment is corresponding to the common port in MSTP territory.

The two stack networkings of layering of still take in Fig. 3 are example, in order to meet the loop detection requirement of the two stack networkings of layering, can in Nei HePBB territory, VPLS territory, carry out MSTP detection respectively, VPLS territory and PBB territory belong to different MSTP examples, block respectively object PW and connect in two examples.In VPLS territory, arrange as follows:

Therefore (1) PE1 is root bridge, STP priority is configured to the highest (priority high equipment as root bridge) on PE1 equipment;

(2) on PE2 equipment, the PW between PE2 and PE1 connects as root PW, and the PW between PE2 and PE3 is as specifying PW;

(3) on PE3 equipment, the PW between PE3 and PE2 is as specifying PW, and the PW between PE3 and PE1 is as blocking-up PW.

Afterwards, in VPLS territory, the PW state based on MSTP will be generated in the PW connection at PE1-PE2-PE3.Under normal circumstances, the PW between PE3-PE1 is blocked (Block), forms normal forward-path between PE1-PE2-PE3, only has when the PW between PE1-PE2-PE3 connects appearance interruption, just can allow the PW state between PE3-PE1 become Forward.

Same, in PBB territory, also can carry out MSTP detection, in PBB territory, arrange as follows:

(1) BEB3 is root bridge, therefore on BEB3 equipment, STP priority is configured to the highest;

(2) on BEB2 equipment, the PW between BEB2 and BEB3 connects as root PW, and the PW between BEB2 and BEB4 is as specifying PW;

(3) on BEB4 equipment, the PW between BEB4 and BEB3 is as specifying PW, and the PW between BEB4 and BEB4 is as blocking-up PW.

Under normal circumstances, it should be noted that the PW between BEB2 and BEB3 is connected to VPLS PW connection, under two stack network environments, VPLS PW and PBB PW are the forward-paths being equal to.In PBB territory, only have BEB4-BEB2-BEB3 to connect and compose normal forward-path, and PW between BEB4-BEB3 is blocked, only has its state when disconnecting between BEB4-BEB2-BEB3 above just can become Forward.

In Hierarchical Virtual Private LAN Service and dual-stack network, after MSTP computing, on PE3 equipment, the PW of PE3-PE1 connects by Block, and on BEB4 equipment, BEB4 equipment connects by Block, to the PW between BEB3 as shown in Figure 4.

For the PE1 equipment in VPLS territory, the unknown unicast coming on local private network side is connected and is broadcast to PE2 through the main PW of VPLS with broadcast traffic, and PE2 receives this message, and is broadcast to PE3 and BEB4, by the two, is transmitted to respectively the CE equipment of local terminal.Now, for PE3 equipment, due to PE3 to the PW between PE1 by Block, so flow can not be repeated to broadcast back PE1; Meanwhile, the PW that arrives PE3 due to BEB4 connects by Block, and therefore, the broadcast traffic that arrives BEB4 also can be dropped.

For the BEB4 in PBB, unknown unicast and the broadcast traffic on local private network side, come, through PBB, forward, because PBB does not have dividing of active and standby PW at present, can not select in advance forward-path, therefore can in PBB example, broadcast, simultaneously because the PW between BEB4 and BEB3 is by Block, therefore message only can be forwarded to BEB2, BEB2 is forwarded to PE1 and PE3 after receiving message, after the VPLS message of PE1 reception public network, forward by local CE equipment, the impact of cutting apart due to level can not be forwarded to the public network side of PE3 again; PE3 equipment, from PE2 receives VPLS message, can be transmitted to local CE equipment, and simultaneously to PE1 device forwards, because the PW between PE3-PE1 is by Block, so message can not be forwarded to PE1 again.

Therefore, the present invention, under the environment of the two stacks of layering, by introduce MSTP in VSI territory, can need to connect and carry out correct blocking-up and forwarding VSI PW according to networking, has ensured the topological state of network, has also improved the reliability of network simultaneously.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, be equal to replacement, improvement etc., within all should being included in the scope of protection of the invention.

Claims

1. in virtual double layer network, avoid a method for loop, it is characterized in that, comprising:

A, in the virtual switch instance VSI of the network equipment of virtual double layer network, enable Multiple Spanning Tree Protocol MSTP, and by VSI example and a MSTP example binding, comprise as follows and shining upon:

By the outgoing interface of the PW place PW equipment of VSI example corresponding to the common port in MSTP territory;

2. method according to claim 1, is characterized in that:

The object media access control MAC address of described BPDU message is the particular address setting in advance, and source MAC is for sending the MAC Address of the equipment of described BPDU message.

3. method according to claim 2, is characterized in that:

The described particular address setting in advance is the sign of 01-80-C2-VSI example.

4. according to the method described in claims 1 to 3 any one, it is characterized in that:

Described virtual double layer network comprises: the two stack networking networks of virtual special local area network VPLS hierarchical network and VPLS/ provider backbone bridge PBB;

Described VSI example comprises: VPLS example and PBB example.

5. method according to claim 4, is characterized in that:

The network equipment of described virtual double layer network is: the edge device PE on service provider network;

6. method according to claim 4, is characterized in that:

The network equipment of described virtual double layer network is: backbone edge bridge BEB;

7. according to the method in claim 2 or 3, it is characterized in that, after described A, further comprise: