CN1949743A

CN1949743A - Method for identifying net load type in multi-protocol sign exchange network

Info

Publication number: CN1949743A
Application number: CNA2005101127778A
Authority: CN
Inventors: 钟来军
Original assignee: Huawei Technologies Co Ltd
Priority date: 2005-10-12
Filing date: 2005-10-12
Publication date: 2007-04-18
Anticipated expiration: 2025-10-12
Also published as: CN100466610C

Abstract

The invention discloses a method for recognizing net load types in multiprotocol label switching (MPLS) network. At the entry end of MPLS network, entry label edge routor (LER0) recognizes net load types corresponding to different messages according to interface types and uses a type code to express the net load type and then packs the code into MPLS message; at the exit end of the MPLS network, exit label edge router (LER1) recognizes net laod type according to the code type and makes corresponding transmission processing according to the net load type. Thus, a label switching path can bear multiple types of messages and before establishing LSP, it need not specially negotiate net load type, thus largely reducing complexity in the network processing course and reducing dependency between various devices in the same network. Besides, because it automatically recognizes net load type and has a certain error correcting mechanism, it reduces error possibility.

Description

A kind of method of in mpls network, payload type being discerned

Technical field

The present invention relates to field of computer network communication, particularly a kind of method of in mpls network, payload type being discerned.

Background technology

The Multi-Protocol Label Switch (MPLS) technology is a kind of rapidly network technology of development in recent years.It is the characteristics of network layer route that this technology combines exchange that the second layer is a link layer and the 3rd layer, and the 3rd layer route is implemented at the edge of network, and adopts the MPLS mark to exchange in the network core of MPLS.So it will have the ATM(Asynchronous Transfer Mode) of service quality improved (QoS) and the Internet Protocol (IP) of automatic route organically combines, and has the two advantage separately, becomes one of network interconnection technology of present main flow.

Layer 2 virtual private network (VPN) based on MPLS is one of wherein popular application, this network diagram as shown in Figure 1, wherein the white rectangle of band numeral is represented the MPLS mark, and grey and black rectangle are represented IP message and the head mark corresponding with the user network type respectively.With the Ethernet is example, and as shown in Figure 2, the payload that the complete ethernet data frame that comprises target MAC (Media Access Control) address and source address can be used as the MPLS message encapsulates, and has added the link layer head of Ethernet in addition.In the middle of a such message, there are two ethernet link layer header informations.In the network of Fig. 1, a MPLS network couples together three customer networks, and the IP routing protocol that moves in three customer networks relies on the IP address to seek route; And in the MPLS network, then rely on the MPLS mark to seek route fully, at this moment the LER (LER) that is in the MPLS network edge is responsible for setting up IP address-based routing iinformation and based on the corresponding relation between the routing iinformation of MPLS mark, in other words, on inlet LER equipment, all client's messages have been coupled with the MPLS mark, then the MPLS mark that adds is previously removed on outlet LER equipment, the Label Switching Routers (LSR) that is in MPLS network centre position then only need exchange according to the MPLS mark.Be called label switched path (LSP) through LSR to the path of LER1 from LER0 among Fig. 1.In two-layer VPN was used, MPLS was as a kind of bearing bed, and it can encapsulate the Frame of multiple heterogeneous networks.

It is network layer information that the characteristics of this two-layer VPN are to provide the MPLS network of service to be indifferent to the 3rd layer of user, service network is that link layer information carries out the configuration of MPLS forwarding relation according to the second layer of user network, the data of user network can be Ethernet, PPP(Point-to-Point Protocol), ATM, frame relay (FR) etc., and the network of multiple like this link layer all may be realized the transmission of link layer traffic by MPLS.Because the difference of link layer, its payload type are also different.And MPLS mechanism can not be distinguished itself, and therefore present way is to limit among a LSP to transmit one type payload.Under LSP static configuration mode, need artificial payload type of specifying this LSP carrying; Under LSP dynamic-configuration mode, need consult the payload type that definite a certain LSP carries by the Routing Protocol and the label distribution protocol that move between the equipment.Therefore, have following deficiency in existing solution: 1. dissimilar payloads can not coexist in same LSP, therefore needs to consume a large amount of LSP numbers, and is difficult for expansion; 2. need type of service is held consultation before setting up LSP, the implementation complexity, and need in the network all devices all to move same protocol could to consult successfully, higher to the dependence of equipment; 3. the payload with dissimilar when mistake is encapsulated among same the LSP, and MPLS can't discern its type, does not therefore have mechanism for correcting errors.

Summary of the invention

In view of this, the objective of the invention is to: a kind of method that payload type in the MPLS network is discerned is provided, uses this method, can make the polytype payload of carrying among the LSP.For achieving the above object, concrete technical scheme is:

A, threshold marker edge router are determined the payload type of this message according to the interface type that receives message from user network, represent this payload type with a type coding, then this encode seal are installed in the MPLS message;

After B, exit marking edge router receive the MPLS message, identify payload type according to the type coding in the MPLS message.

After the described step B, can further include: according to this payload type, payload in the described MPLS message is converted to the message of original subscriber's network correspondence, and determine interface according to the label of MPLS heading, if the type of payload type and corresponding outgoing interface is consistent, then this message is sent to targeted customer's network via the interface of corresponding types, if payload type and corresponding outgoing interface Type-Inconsistencies, then do not send this message and notify the control plane of exit marking router, so that control plane is further processed type of message and the inconsistent problem of interface type of solving.

LER all has default type of message coding schedule, and this type of message coding schedule has been stored the corresponding relation of payload type and coding.

In the steps A, threshold marker edge router basis is from the payload type of the message of user network, by searching the payload type coding that described type of message coding schedule obtains the type correspondence; Among the step B, the exit marking edge router obtains the corresponding payload type of this coding according to the coding of the payload type in the MPLS message by searching described type of message coding schedule.

Described type of message coding schedule is artificial appointment or definite by normal structure.

When encapsulating the MPLS message in the steps A, type coding is stored in the reservation position of the control word that is arranged in MPLS labeled slots bottom; Among the described step B, the exit marking edge router reads control word above-mentioned in the MPLS message, obtains the type coding of this message, obtains corresponding payload type by the type coding.

Preferably, the type code width is 4 bits.The width of the type coding can be adjusted accordingly according to actual conditions, may be less than 4 bit, and also may be greater than 4 bits.

Perhaps adopt following replacement scheme: default a certain payload type is a default type in described LER, when encapsulation MPLS message, select certain width stored payload type indication code in the reservation position of the control word that is arranged in MPLS labeled slots bottom, described steps A is: the threshold marker edge router identifies the payload type of different messages according to the interface type that receives message, if payload type is a default type, then in the payload type indication code, write the default type sign, if payload type is not a default type, then the threshold marker edge router writes non-default type sign in the payload type indication code, opens up the payload type territory stored payload type coding of certain byte wide between MPLS header and payload in addition;

Preferably, described payload type indication code width is 1 bit, and the payload type code width is 2 bytes (i.e. 16 bits); The width of this payload type indication code and type coding can be adjusted respectively accordingly according to actual conditions.

Described step B is: the exit marking edge router reads the payload type indication code from the MPLS message, if indication code is the default type sign, then the payload in the described MPLS message is converted to the message of default type;

If indication code is non-default type sign, then the exit marking edge router reads the type coding in the payload type territory, obtain corresponding payload type by the type coding, and deletion payload type territory, determine corresponding outgoing interface type by MPLS header label again, delete the MPLS heading then, be about to the message that payload in the described MPLS message is converted to original subscriber's network corresponding types.

If indication code is the default type sign, then after step B, increase following steps: will be sent to the interface of default type by the payload of the default type that is converted to;

If indication code is non-default type, then after step B, increase following steps: the consistency to payload type and corresponding outgoing interface type is carried out verification, if the type of payload type and corresponding outgoing interface is consistent, then this message is sent to targeted customer's network via the interface of corresponding types, if payload type and corresponding interface Type-Inconsistencies, then do not send this message and notify the control plane of exit marking router, so that control plane is further processed type of message and the inconsistent problem of interface type of solving.

According to method proposed by the invention, the LER of the port of export is according to the type coding that extracts from the MPLS message, can identify the payload type of this message and transmit processing accordingly, therefore can carry polytype message simultaneously among a LSP.So, the number of LSP significantly reduces in the MPLS network, and sets up the payload type that need not every LSP is carried before the LSP and hold consultation specially, therefore reduces the complexity of network processes process and the degree of dependence of the interior equipment room of network greatly.Simultaneously,, possess certain mechanism for correcting errors, reduced the possibility that mistake occurs because the method that the present invention proposes is discerned automatically to payload type.

Description of drawings

Figure 1 shows that application network schematic diagram based on the two-layer VPN of MPLS;

Fig. 2 is MPLS two-layer VPN encapsulation Ethernet data frame format schematic diagram;

Figure 3 shows that the embodiment of the invention one directly indicates the MPLS message schematic diagram of payload type by control word in PWE3;

Figure 4 shows that the embodiment of the invention one directly indicates the MPLS message workflow diagram of payload type by control word in PWE3;

Figure 5 shows that the embodiment of the invention two indicates the MPLS message schematic diagram of payload type indirectly by control word in PWE3;

Figure 6 shows that the embodiment of the invention two indicates the MPLS message workflow diagram of payload type indirectly by control word in PWE3.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with specific embodiment.

The Pseudo Wire Emulation Edge-to-Edge (PWE3) of internet engineering duty group (IETF) definition is considered to the tunneling that two-layer VPN adopts most probable.Use PWE3 mechanism, operator can transfer to all transport services among the network (as IP/MPLS) of a fusion.From user's angle, can think that the dummy line of PWE3 simulation is a kind of link or circuit of special use.In the PWE3 technology, increase the control word CW of one 32 bit in the bottom of MPLS labeled slots, the reservation position of 12 bits is wherein arranged.Key of the present invention is exactly to utilize the reservation position of this 12 bit, utilizes the type of this reservation position recorded message payload at MPLS Web portal place, determines the type of message payload at the MPLS network exit according to keeping record in the position.

Below lifting two technology implementation examples is elaborated.Wherein embodiment one directly indicates payload type by the reservation position of control word.Its MPLS message schematic diagram will keep the position that the type coding of sign payload type is filled in the 4 bits conduct in the position in the present embodiment, and this byte length can be adjusted according to actual needs also as shown in Figure 3.MPLS Web portal end equipment is filled in corresponding type coding according to the payload type that identifies, and port of export equipment is according to the type code identification and verification payload type.The concrete steps of workflow are as shown in Figure 4:

Step 401: LER0 sets up a label switched path LSP to port of export LER LER1 from MPLS arrival end LER;

Step 402～step 403: at the arrival end of MPLS network, insert LER0 from the message of user network via the corresponding types interface of arrival end LER LER0, these interfaces may be types such as Ethernet, PPP, ATM or FR.Every kind of interface transmits the message of corresponding with it specific payload type.LER0 goes out the payload type of this message according to the type identification of the interface that transmits message, and when payload being encapsulated in the MPLS message, determining the type coding of this payload type correspondence and the type coding is inserted the position that control word CW keeps regulation in the position by searching a default type of message coding schedule.This type of message coding schedule is as shown in table 1:

Payload type	Type coding
Payload type	Type coding	Ethernet	0
PPP	1	Ethernet	0
PPP	1	ATM	2
FR	3	ATM	2
FR	3	......	......

Table 1

If the bit number that the payload type coding takies is n, then the right one row are 0 to 2 in this table ⁿ-1 numeral or wherein a kind of arbitrarily arrangement of part numeral.In the present embodiment, the bit number that payload type coding takies is 4, and then the right one row are 0 to 15 or wherein any one arrangement of part numeral in the payload type coding schedule.Its content can be stipulated by human configuration or by the standard that normal structure is set up.

Step 404:MPLS message sends to port of export LER1 at the MPLS network via label switched path LSP;

Step 405: when port of export LER1 received a MPLS message, the type coding that writes in the reservation position according to control word CW in the message found the corresponding payload type of this coding by searching content with the identical type of message coding schedule of table 1.This search procedure is an index with the type coding, and the result who searches is a payload type.Port of export LER1 selects the outgoing interface of corresponding types according to MPLS header label.Port of export LER1 removes the MPLS mark, and soon the payload in the MPLS message is converted to the message of corresponding types, and the payload type and the consistency of the outgoing interface type of correspondence are carried out verification.

Step 406～step 407: if payload type is consistent with the interface type of port of export LER1, then message is sent to user network via the interface of LER1 correspondence, otherwise do not send, notify control plane simultaneously, control plane can further be handled payload type and the inconsistent problem of interface of solving in view of the above.

Above embodiment is the method that payload type is directly indicated in the reservation position of employing control word, and following embodiment indicates payload type indirectly with control word.Whether the schematic diagram of MPLS message keeps the payload type indication territory of adopting one 1 bit in the position in control word and indicates and also have the payload type territory of another one 2 bytes to come the stored payload type coding between MPLS heading and the payload as shown in Figure 5.The concrete operations step is as shown in Figure 6:

Step 601: LER0 sets up a label switched path LSP to port of export LER from MPLS arrival end LER, and specifies one type payload to be the default type of this LSP;

Step 602-step 605: at the arrival end of MPLS network, LER0 is according to the payload type of the type identification outgoing packet of interface, if this payload is a default type, then inserts 0 in payload type indication territory; If this payload is not the acquiescence payload, then in payload type indication territory, insert 1, between the payload of MPLS message and MPLS heading, open up the payload type territory of one 2 byte; By searching the type coding table, in the payload type territory, write the type coding of this payload type correspondence;

Step 606:MPLS message is transmitted by LSR in the MPLS network, arrives the port of export at last;

Step 607-step 612: when port of export LER1 receives a MPLS message, read the content in the payload type indication territory, if 0, directly payload is forwarded to default interface after then removing the MPLS mark according to default type; If 1, read the type coding in payload type territory again, obtain the type of this payload by retrieval type coding table, and delete this payload type territory.Then remove the MPLS mark earlier, payload is converted to the message of corresponding types, port of export LER1 selects the outgoing interface of corresponding types according to MPLS header label, again the consistency of payload type and corresponding outgoing interface type is carried out verification, if payload type is consistent with interface type, then message is sent to user network via the interface of LER1 correspondence, otherwise do not send, notify control plane simultaneously, control plane can further be handled payload type and the inconsistent problem of interface of solving in view of the above.

This replacement scheme relatively is adapted in the MPLS network, the situation that the relative other types of the traffic carrying capacity of a certain payload type are bigger.

It should be noted that in the above illustrated embodiment that wherein position and the width of type coding in control word includes but not limited to foregoing description.Though above embodiment is to be example to adopt the PWE3 The Application of Technology in the MPLS network two-layer VPN, processing method of the present invention has nothing to do with concrete tunneling, so long as all applicable based on the two-layer VPN of MPLS network.

Claims

1, a kind of method of in multi protocol label exchange MPLS network payload type being discerned is characterized in that the method includes the steps of:

A, threshold marker edge router are determined the payload type of this message correspondence according to the interface type that receives message from user network, represent this payload type with a type coding, then this encode seal are installed in the MPLS message;

After B, exit marking edge router receive the MPLS message, identify corresponding payload type according to the type coding in the MPLS message.

2, method according to claim 1, it is characterized in that, after described step B, increase following steps: the message that the payload in the described MPLS message is converted to original subscriber's network correspondence, and determine interface according to the label of MPLS heading, if the type of payload type and corresponding outgoing interface is consistent, then this message is sent to targeted customer's network via the interface of corresponding types, if payload type and corresponding outgoing interface Type-Inconsistencies then do not send this message and notify the control plane of exit marking edge router.

3, method according to claim 1 is characterized in that, LER all has default type of message coding schedule, and this type of message coding schedule has been stored the corresponding relation of payload type and coding.

4, method according to claim 3 is characterized in that: in the steps A, threshold marker edge router basis is from the payload type of the message of user network, by searching the payload type coding that described type of message coding schedule obtains the type correspondence;

Among the step B, the exit marking edge router obtains the corresponding payload type of this coding according to the coding of the payload type in the MPLS message by searching described type of message coding schedule.

5, method according to claim 3 is characterized in that, described type of message coding schedule is artificial appointment or definite by normal structure.

6, according to claim 1,2,3,4 or 5 described methods, it is characterized in that, when encapsulating the MPLS message in the steps A, type coding is stored in the reservation position of the control word that is arranged in MPLS labeled slots bottom;

Among the described step B, the exit marking edge router reads control word above-mentioned in the MPLS message, obtains the type coding of this message, obtains corresponding payload type by the type coding.

7, method according to claim 6 is characterized in that, the type code width is 4 bits.

8, according to claim 1,3,4 or 5 described methods, it is characterized in that, default a certain payload type is a default type in described LER, when encapsulation MPLS message, select certain width stored payload type indication code in the reservation position of the control word that is arranged in MPLS labeled slots bottom

Described steps A is: the threshold marker edge router identifies the payload type of different messages according to the interface type that receives message, if payload type is a default type, then in the payload type indication code, write the default type sign, if payload type is not a default type, then the threshold marker edge router writes non-default type sign in the payload type indication code, opens up the payload type territory stored payload type coding of certain byte wide between MPLS header and payload in addition;

If indication code is non-default type sign, then the exit marking edge router reads the type coding in the payload type territory, obtain corresponding payload type by the type coding, and deletion payload type territory, determine corresponding outgoing interface by MPLS header label again, delete the MPLS heading then, be about to the message that payload in the described MPLS message is converted to original subscriber's network corresponding types.

9, method according to claim 8 is characterized in that, if indication code is the default type sign, then after step B, increases following steps: will be sent to the interface of default type by the payload of the default type that is converted to;

If indication code is non-default type, then after step B, increase following steps: the consistency to payload type and corresponding outgoing interface type is carried out verification, if the type of payload type and corresponding outgoing interface is consistent, then this message is sent to targeted customer's network via the interface of corresponding types, if payload type and corresponding interface Type-Inconsistencies then do not send this message and notify the control plane of egress router;

10, method according to claim 8 is characterized in that, described payload type indication code width is 1 bit, and the payload type code width is 2 bytes.