CN100396039C

CN100396039C - Method for realizing MPLS network intercommunication based on heterogeneous medium

Info

Publication number: CN100396039C
Application number: CNB2005100004094A
Authority: CN
Inventors: 张立华; 胡春哲; 龚钧; 范宇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-01-07
Filing date: 2005-01-07
Publication date: 2008-06-18
Anticipated expiration: 2025-01-07
Also published as: CN1801750A

Abstract

The present invention relates to a method for realizing the intercommunication of an MPLS network based on heterogeneous media, which comprises the following steps: firstly, an interface address between PE equipment and self end user lateral edge equipment CE is allocated on the PE equipment of provider edge equipment as an IP address of opposite end CE equipment; secondly, an ARP list item corresponding to the IP address of the opposite end CE equipment is arranged on self end CE equipment according to the IP address which is allocated by the PE equipment; finally, the self end CE equipment and the opposite end CE equipment are communicated with each other based on heterogeneous medium PE equipment and the ARP list item. The method can be used for ensuring that the self end CE does not depend on a free ARP function but can give a correct reply when requested with the ARP, and can be used for realizing that only PE equipment with same network section can reply to the ARP request transmitted by the CE equipment.

Description

Realize the method for MPLS network interworking based on foreign medium

Technical field

The present invention relates to communication field, relate in particular to a kind of method that realizes the MPLS network interworking based on foreign medium.

Background technology

Along with social development, trend of economic globalization is more and more obvious, more enterprise sets up branch more and more, the company personnel is also along with the foundation of branch is moved, therefore pressing for telecom operators provides two layers of link to connect, so that the enterprise network of each branch's tissue of enterprise oneself, the company personnel can visit Intranet in the place beyond enterprise easily simultaneously.

At first, telecom operators are that the mode with lease special line (Leased Line) is that enterprise provides two layers of link, but adopt this mode not only building time is long, cost an arm and a leg, and are difficult to manage.So, rise along with ATM and frame relay (Frame Relay) technology, telecom operators transfer to use the virtual circuit mode to provide two layers of link of point-to-point to connect as the client, connect based on this two layers of link, the client only needs to set up the three-layer network of oneself thereon with data flow such as carrying IP, IPX, just can organize the enterprise network of oneself easily.

Compare with the lease special line, the operator of employing virtual circuit mode provides the time of service short, price is low, yet in order on networks of different type (as ATM, FR), to provide Virtual Private Network (VPN) professional and Internet business, operator need build and safeguard two independently networks, and its cost is still higher; In addition, when adopting the virtual circuit mode to increase website, the keeper need carry out a large amount of configuration efforts; And the network transmission speed that adopts this mode to set up is slower.Therefore, pressing for a kind ofly not only can provide IP service and two-layer VPN service on the net simultaneously same, and can conveniently set arbitrary velocity, disposes better simply technology.

So, arise at the historic moment based on the technology of the two-layer VPN (hereinafter to be referred as MPLS L2VPN) of MPLS.In simple terms, MPLS L2VPN is exactly the Layer 2 data of transparent transmission user on the MPLS network.From user's angle, this MPLS network is exactly two layers of switching network, by this network, can set up two layers of connection between different websites.

In order to support that two layers of dissimilar links can intercommunication, just support the L2VPN internetworking, when setting up the L2VPN connection, the L2VPN interface type of service provider's edge device (PE) adopts IP link interconnected (Ip-interworking), and on the MPLS network transparent transmission user's three layer data (IP message).

After provider edge equipment PE is encapsulated as and is activated by physics based on the interconnected interface of foreign medium L2VPN, start and set up L2VPN and connect; After L2VPN set up connection, just expression was used for the physical link intercommunication of transparent transmission, and then PE allows L2VPN to transmit.As long as the IP link of two ends user side edge devices (CE) is activated, and the physical link of L2VPN simulation also is activated, the CE equipment at two ends just can carry out the IP message alternately.

Based on above-mentioned technology, the scheme of the method for ethernet vlan intercommunication has appearred realizing based on foreign medium at present.Its flow process is: at first, equipment CE-A carries out link layer packaging with message, is forwarded to equipment PE-A by foreign medium L2VPN then; When equipment PE-A receives link layer message from equipment CE-A, at first remove link layer packaging, then IP message or ARP message are given the MPLS network be transparent to opposite equip. PE-B (L2VPN connect set up after, the link layer control message that equipment CE-A sends is transparent transmission not, is handled by equipment PE-A; For the data message of non-IP or ARP agreement, as the message of agreements such as MPLS, ISIS, IPX, transparent transmission does not abandon without exception; IP or ARP message then are transparent to method, apparatus PE-B.); The link layer type that last opposite equip. PE-B is encapsulated as oneself with the IP message sends to the equipment CE-B of local terminal.

In this scheme, Ethernet interface or the sub-interface of PE can only link to each other with a CE, do not support situation about linking to each other with a plurality of CE or other equipment, otherwise the MAC Address that PE acquires other CE or equipment can occur, cause transmitting obstructed problem by hub (HUB) or ether switch.

When the incoming interface of equipment PE is received the ARP request of equipment CE,, all use the MAC Address feedback response message of oneself no matter to any destination;

The process that the link layer type that equipment PE-B is encapsulated as oneself with message sends to the equipment CE-B of local terminal is mainly reflected in following several mode:

1, when the MAC Address of static configuration equipment CE on the interface of equipment PE and direct-connected equipment CE, then when sending message, uses CE this MAC Address.

2, when the IP address of static configuration CE on the interface of equipment PE and direct-connected equipment CE, then when CE sends message, if find not have configuring static MAC, and do not acquire dynamic MAC, then initiatively send the ARP request to CE, the source and destination IP address of request is the IP address of configuration, i.e. the IP address of CE.After CE receives this request, can think has the equipment identical with the IP address of oneself on the network, if support to send the gratuitous ARP response message, then equipment PE can acquire the MAC Address of local CE, if do not support to send the gratuitous ARP response message, then equipment PE learns the MAC Address less than local CE, and forwarding will get nowhere.

3, the mode that enables to broadcast when configuration on the interface of equipment PE and direct-connected equipment CE then when CE sends the IP message, if find both there be not static MAC, does not have dynamic MAC again, and the IP address of static configuration CE not, and then target MAC (Media Access Control) address adopts broadcast address.

If above-mentioned three kinds of modes all are not provided with, then equipment PE-B will all abandon from the message that opposite equip. PE-A receives, not transmit.

By the technical scheme of above-mentioned prior art as can be seen: because when the incoming interface of equipment PE receives that the ARP of equipment CE asks, no matter to any destination, all use the MAC Address feedback response message of oneself, so equipment PE needs response to the ARP request that any equipment CE sends.

In addition, when equipment PE initiatively when CE initiates the ARP request, the source and destination IP address of request is the IP address of configuration, after CE receives this request, can think has the equipment identical with the IP address of oneself on the network, like this, the equipment CE of necessarily requiring has the function that sends gratuitous ARP and could reply the ARP request that PE sends, otherwise can think address conflict and reject response.Necessarily require equipment CE to have the ability that sends gratuitous ARP like this.

To sum up analyze and learn: two technical problems of main existence in the prior art:

1, equipment PE needs response to the ARP request that any equipment CE sends.

2, the function that necessarily requires equipment CE to have the transmission gratuitous ARP could be replied the ARP request that equipment PE sends.

Summary of the invention

In view of above-mentioned existing in prior technology problem, the purpose of this invention is to provide and a kind ofly realize that based on foreign medium the method for MPLS network interworking, this method have solved the problem that the function that necessarily requires equipment CE to have to send gratuitous ARP could be replied the ARP request that equipment PE sends.

The objective of the invention is to be achieved through the following technical solutions:

A kind of method based on foreign medium realization MPLS network interworking provided by the invention comprises:

A, be the IP address of opposite end CE equipment at the interface IP address between configuration this PE equipment and local terminal user side edge device CE on the provider edge equipment PE;

B11, local terminal CE equipment send the ARP request message, and local end PE equipment returns response message to local terminal CE equipment after receiving described ARP request message;

After B12, local terminal CE equipment are received described response message, generate the ARP list item of the MAC Address corresponding relation of local terminal CE equipment and opposite end CE equipment room;

C, local terminal CE equipment and opposite end CE equipment room communicate based on foreign medium PE equipment and described ARP list item.

Wherein, described steps A also comprises:

On the interface of PE equipment and local terminal CE equipment room, enable the Layer 2 virtual private network function.

Wherein, the IP address of described opposite end CE equipment is in same address network segment with the IP address of local terminal CE equipment.

Wherein, in step B11, described local end PE equipment receives behind the described ARP request message that process from response message to local terminal CE equipment that return further comprises:

Local end PE equipment is received described ARP request message, and the IP address of local end PE equipment interface configuration and the IP address of CE equipment are in the same network segment, then with the IP address of the far-end CE equipment of local end PE equipment disposition, and local terminal CE equipment is returned by response message in corresponding local end PE equipment and the media access control MAC address of CE equipment room.

Wherein, between described step B12 and step C, also comprise:

D, in PE equipment, preserve the MAC Address of the IP address correspondence of connected CE equipment.

Wherein, described step D further comprises:

The MAC Address of the IP address correspondence of the connected CE equipment of static configuration is a broadcast mode in PE equipment; Or,

The MAC Address of the IP address correspondence of the connected CE equipment of static configuration in PE equipment; Or,

The IP address of the connected CE equipment of static configuration in PE equipment, and according to this IP address search or generate described ARP list item, writing down the MAC Address of the IP address correspondence of described CE equipment in the ARP list item.

Wherein, when local terminal CE equipment when opposite end CE equipment sends message, described step C further comprises:

C1, local terminal CE equipment with message to be sent according to the encapsulation of described ARP list item on the IP address of far-end CE equipment, and the two layer MAC address of local end PE equipment, and sending;

C2, local end PE equipment remove two layer MAC address after receiving described message, and encapsulate based on multiprotocol label switching MPLS, send to far-end PE equipment;

C3, far-end PE equipment are separated the MPLS encapsulation process after receiving described message, obtain the purpose IP address of message carrying;

C4, far-end PE equipment determine the mac address information of corresponding far-end CE equipment according to described purpose IP address, and according to described mac address information described message are sent to far-end CE equipment.

Wherein, when opposite end CE equipment when local terminal CE equipment returns response message, described step C further comprises:

C5, at opposite end CE equipment according to the IP address of described ARP list item with local terminal CE equipment in the response message encapsulation, and the two layer MAC address of opposite end PE equipment, and sending;

C6, opposite end PE equipment remove two layer MAC address after receiving described message, and encapsulate based on multiprotocol label switching MPLS, send to local end PE equipment;

C7, local end PE equipment are separated the MPLS encapsulation process after receiving described message, obtain the purpose IP address of message carrying;

C8, local end PE equipment determine the mac address information of corresponding local terminal CE equipment according to described purpose IP address, and according to described mac address information described message are sent to local terminal CE equipment.

As seen from the above technical solution provided by the invention, method of the present invention is owing to be the IP address of opposite end CE equipment at the interface IP address between configuration this PE equipment and local terminal user side edge device CE on the provider edge equipment PE equipment, so can realize when local terminal CE request ARP, adopt the IP address of far-end CE on described local terminal CE equipment, to generate the ARP list item of going to opposite end CE equipment, thereby guarantee that local terminal CE does not rely on the gratuitous ARP function and provides correct replying.

In addition, because the IP address of the described opposite end of configuration CE equipment is in same address network segment with the IP address of local terminal CE equipment on PE equipment, all need the problem that responds so solved ARP request that equipment PE sends any equipment CE, thereby guarantee that the ARP that CE equipment is sent asks, and has only the PE equipment of same network segment just can reply.

Description of drawings

Fig. 1 is a network topological diagram of the present invention;

Fig. 2 is a flow chart of the present invention;

Fig. 3 is the conveying flow figure of message among the present invention.

Embodiment

The two CE equipment that method of the present invention requires to transmit message in implementation procedure are in identical address network segment, and as shown in Figure 1, user side edge device A (CE-A) must be in identical address network segment with user side edge device B (CE-B).

In addition, still as shown in Figure 1, adopt Ethernet or VLAN (VLAN) to be connected between CE-A and edge device A (PE-A) that operator provides, employing PPP(Point-to-Point Protocol) or ATM(Asynchronous Transfer Mode) are connected between CE-B and edge device B (PE-B) that operator provides.

The specific implementation of method of the present invention specifically comprises as shown in Figure 2:

Step S210 is the IP address of opposite end CE equipment at the interface IP address between this PE equipment of configuration and local terminal user side edge device CE on the provider edge equipment PE equipment.

After finishing above-mentioned layoutprocedure, also need on the interface of PE equipment and local terminal CE equipment room, enable the Layer 2 virtual private network function.

Above-mentioned two is the basis that equipment CE-A and equipment CE-B carry out communication.

For example as shown in Figure 1, with the interface configuration between CE-A and PE-A be the IP address of CE-B; Because this interface has enabled the L2VPN function simultaneously, so the IP address of configuration can not cause generating network segment route; But the ARP module can work normally with the generic interface configuration of IP address after processing procedure without any difference, promptly can handle the ARP request message that local terminal CE-A side is sent, and return corresponding arp response message to CE-A, on PE-A equipment, produce the dynamic ARP entry of going to CE-A equipment simultaneously, on CE-A, generate the ARP list item of going to CE-B.

Step S220 sets up the ARP list item of the IP address correspondence that generates opposite end CE equipment on described local terminal CE equipment according to the IP address of PE equipment disposition.

In this step, carry out in two kinds of situation.

First kind of situation: the ARP list item of going to opposite end CE equipment according to IP address static configuration on described local terminal CE equipment of PE equipment disposition.This kind mode has no requirement to PE equipment, i.e. the direct-connected interface of PE and the CE IP address that can dispose far-end CE, the IP address that also can dispose local terminal CE.

Second kind of situation: the IP address according to the PE equipment disposition dynamically generates the ARP list item of going to opposite end CE equipment on described local terminal CE equipment.Under second kind of situation, concerning CE, there is not special requirement yet, send the ARP request normally and get final product.Concerning PE, understand some difference, the IP address that the direct-connected interface of PE and CE must dispose far-end CE, because this interface has enabled the L2VPN function simultaneously, so the IP address of configuration can not cause generating network segment route, when but the ARP module can normally be worked and is configured the IP address with generic interface without any difference, therefore can handle the ARP request message that local terminal equipment CE side is sent, and the feedback arp reply, the dynamic ARP entry of going to CE produced simultaneously.

The specific implementation step is:

At first, local terminal CE equipment sends the ARP request message;

Then, local end PE equipment is received described ARP request message, and the IP address of local end PE equipment interface configuration and the IP address of CE equipment are in same address network segment, then with the IP address of the far-end CE equipment of local end PE equipment disposition, and local terminal CE equipment is returned by response message in corresponding local end PE equipment and the media access control MAC address of CE equipment room;

At last, after local terminal CE equipment is received described response message, generate the ARP list item of the MAC Address corresponding relation of local terminal CE equipment and opposite end CE equipment room.

Still as shown in Figure 1, equipment CE-A end sends the ARP request, and request address is the IP address 10.1.1.2 of far-end CE-B.The direct-connected interface enable of PE-A the foreign medium of L2VPN interconnected, to the ARP message be not transparent to far-end CE-B but on give the ARP module of this machine.Since the interface configuration of PE-A the IP address of far-end CE-B, and be same address network segment with CE1, so can correctly handle this ARP request, provide arp reply.The content of replying is that the MAC Address of IP address 10.1.1.2 correspondence is the MAC Address of PE-A and the direct-connected interface of CE-A.CE-A receives the ARP message of replying, and generates the dynamic ARP entry of going to address 10.1.1.2.

At make a call to the mac address information that two layer encapsulation time need know CE-A of PE-A, therefore, need on PE-A, dispose IP address and the MAC Address correspondence relationship information of the CE-A that is connected with PE-A to CE-A; So execution in step S230, the MAC Address of the IP address correspondence of the connected CE equipment of preservation in PE equipment.

Three kinds of situations of concrete branch in this step:

One, the MAC Address of the IP address correspondence of the connected CE equipment of static configuration is a broadcast mode in PE equipment.In this case, need not to know the MAC Address of CE side, all messages are played two layers of encapsulation and are all sent with broadcast mode.

Two, the MAC Address of the IP address correspondence of the connected CE equipment of static configuration in PE equipment.In this case, enable the interface of L2VPN foreign medium interconnection, the MAC of the interface of the CE that static configuration is direct-connected.All PE all adopt this MAC to the two layers of encapsulation of making a call to of the message of CE.

Three, the IP address of the connected CE equipment of static configuration in PE equipment, and according to this IP address search or generate described ARP list item, writing down the MAC Address of the IP address correspondence of described CE equipment in the ARP list item.

At the third in this case, described in PE equipment the IP address of the connected CE equipment of static configuration, and still as shown in Figure 1 according to this IP address search or the process that generates described ARP list item:

At first, static IP address of specifying the CE-A interface on the direct-connected interface of PE-A and CE-A; This IP address is as the next hop address of PE toward CE;

Secondly, when the message that far-end CE-B sends via MPLS network (PE-B and PE-A) finds it is to go to CE-A, at first jump and outgoing interface is searched the ARP table,, then obtain corresponding M AC address and described message is played two layers of encapsulation mail to CE-A if find the list item of correspondence according on the interface next; If do not find corresponding list item, then report ARP MISS (ARP misses) message, to start the ARP discovery feature, send the ARP request message, the content of ARP request message is next-hop ip address (being the IP address of the direct-connected CE of the static appointment of interface);

Subsequently, the ARP request message is issued CE-A, and CE-A provides arp reply, and the content of replying is the pairing MAC Address in IP address of CE-A;

At last, response message arrives PE-A, PE-A not this ARP message of transparent transmission but on give this machine the ARP module, generate the dynamic ARP entry of going to CE-A, PE-A is acquired go to the dynamic ARP entry of CE-A, on PE-A, set up the ARP list item that has generated CE-A this moment.

After having set up corresponding ARP list item respectively on CE equipment and the PE equipment, then execution in step S240 promptly just can communicate based on described ARP list item and foreign medium PE equipment between the CE equipment.

Still referring to illustrated in figures 1 and 2, be example to send message by CE-A to CE-B, the transmission processing procedure of concrete message is as follows:

Step S241, CE-A equipment with message to be sent according to the encapsulation of described ARP list item on the IP address of far-end CE-B equipment, and the two layer MAC address of PE-A equipment, and send PE-A.

Step S242, PE-A equipment removes two layer MAC address after receiving described message, and encapsulate based on multiprotocol label switching MPLS, send to PE-B equipment, promptly between PE-A and PE-B, no longer carry out the transmission of message based on MAC Address, and be based on the transmission that mpls protocol carries out message, exactly because also this reason, described CE equipment and PE equipment just are called foreign medium.

Step S243, PE-B equipment separate the MPLS encapsulation process after receiving described message, obtain the purpose IP address of message carrying.

Step S244, PE-B equipment is determined the mac address information of corresponding CE-B equipment according to the IP address of described CE-B, and described message is sent to CE-B equipment.If the MAC Address of the IP address correspondence of configuration CE-B equipment is a broadcast mode on PE-B equipment, then all messages are played two layers of encapsulation and are all sent to CE-B with broadcast mode; If the MAC Address of the IP address correspondence of the connected CE-B equipment of static configuration in PE-B equipment, then all PE-B all adopt this MAC Address to the two layers of encapsulation of making a call to of the message of CE-B, send to CE-B then; If the IP address of the connected CE-B equipment of static configuration in PE-B equipment, and according to this IP address search or generate described ARP list item, obtain the MAC Address of the IP address correspondence of described CE-B equipment, all adopt this MAC Address to play two layers of encapsulation to the message of CE-B all PE-B then, send to CE-B.

Above-mentioned steps S241 has provided among Fig. 1 by the entire process process of CE-A to CE-B transmission message, for basic identical to processing procedure and above-mentioned processing procedure that CE-A sends message (as returning response message etc.) by CE-B to step S244; Promptly when by CE-B when CE-A sends message, still need to be provided with on CE-B and the PE-B the corresponding ARP list item of preservation, the process step 210 as previously described that is provided with is similar to step 240, after corresponding ARP list item is set up and is finished, the process of transmitting of corresponding message can be regarded as the inverse process of step S241 to the described processing procedure of step S244.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1. the method based on foreign medium realization MPLS network interworking is characterized in that, comprising:

2. method according to claim 1 is characterized in that, described steps A also comprises:

3. method according to claim 2 is characterized in that, the IP address of described opposite end CE equipment is in same address network segment with the IP address of local terminal CE equipment.

4. method according to claim 1 is characterized in that, in step B11, described local end PE equipment receives behind the described ARP request message that process from response message to local terminal CE equipment that return further comprises:

5. according to claim 3 or 4 described methods, it is characterized in that, between described step B12 and step C, also comprise:

6. method according to claim 5 is characterized in that, described step D further comprises:

7. method according to claim 5 is characterized in that, when local terminal CE equipment when opposite end CE equipment sends message, described step C further comprises:

8. method according to claim 5 is characterized in that, when opposite end CE equipment when local terminal CE equipment returns response message, described step C further comprises: