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
Current assignee: Jiang Wentao
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 identifying payload types in a multi-protocol label switching (MPLS) network. At the ingress port of the MPLS network, the ingress label edge router LER0 recognizes the payload types corresponding to different messages according to the interface type, and uses a type code to represent the payload type, and then encapsulates the code into the MPLS message; at the MPLS network egress At the end, the egress labeled edge router LER1 identifies the payload type according to the type code, and performs corresponding forwarding processing according to the payload type. According to the method proposed by the present invention, a label switched path (LSP) can carry multiple types of messages at the same time, and there is no need to specifically negotiate the payload type before establishing the LSP, so the complexity of the network processing process is greatly reduced, and the number of messages in the same network is reduced. Dependencies between devices. At the same time, since the method proposed by the invention automatically identifies the payload type, it has a certain error correction mechanism, which reduces the possibility of errors.

Description

A Method for Identifying Payload Types in Multiprotocol Label Switching Networks

技术领域technical field

本发明涉及计算机网络通讯领域，特别涉及一种在多协议标记交换网络中对净荷类型进行识别的方法。The invention relates to the field of computer network communication, in particular to a method for identifying payload types in a multi-protocol label switching network.

背景技术Background technique

多协议标记交换(MPLS)技术是近年来发展迅速的一种网络技术。这一技术结合了第二层即链路层的交换和第三层即网络层路由的特点，第三层的路由在网络的边缘实施，而在MPLS的网络核心采用MPLS标记进行交换。因此它将具有完善服务质量(QoS)的异步传输模式(ATM)和自动路由的因特网协议(IP)有机的结合起来，并具有二者各自的优点，成为目前主流的网络互连技术之一。Multiprotocol Label Switching (MPLS) technology is a network technology that has developed rapidly in recent years. This technology combines the features of Layer 2, link layer switching and Layer 3, network layer routing. Layer 3 routing is implemented at the edge of the network, while MPLS labels are used for switching at the core of the MPLS network. Therefore, it organically combines the Asynchronous Transfer Mode (ATM) with perfect quality of service (QoS) and the Internet Protocol (IP) with automatic routing, and has their own advantages, and has become one of the mainstream network interconnection technologies at present.

基于MPLS的二层虚拟专用网(VPN)是其中最为流行的应用之一，该网络示意图如图1所示，其中带数字的白色矩形代表MPLS标记，而灰色和黑色矩形分别代表IP报文和与用户网络类型对应的头部标记。以以太网为例，如图2所示，包含目的MAC地址和源地址的完整以太网数据帧可以作为MPLS报文的净荷封装起来，并且另外加上了以太网的链路层头部。在这样的一个报文当中，存在两个以太网链路层头部信息。在图1的网络中，一个MPLS网络将三个客户网络连接起来，在三个客户网络中运行的IP路由协议，依靠IP地址来寻找路由；而在MPLS网络中，则完全依靠MPLS标记来寻找路由，这时处于MPLS网络边缘的标记边缘路由器(LER)负责建立基于IP地址的路由信息和基于MPLS标记的路由信息之间的对应关系，换句话说，在入口LER设备上，所有的客户报文被加上了MPLS标记，在出口LER设备上则将前面添加的MPLS标记去除，处于MPLS网络中间位置的标记交换路由器(LSR)则只需要根据MPLS标记进行交换。图1中从LER0经LSR到LER1的路径叫做标记交换路径(LSP)。在二层VPN应用中，MPLS作为一种承载层，它可以封装多种不同网络的数据帧。MPLS-based Layer 2 Virtual Private Network (VPN) is one of the most popular applications. The schematic diagram of the network is shown in Figure 1, where the white rectangles with numbers represent MPLS marks, while the gray and black rectangles represent IP packets and A header tag corresponding to the user's network type. Taking Ethernet as an example, as shown in Figure 2, the complete Ethernet data frame including the destination MAC address and source address can be encapsulated as the payload of the MPLS message, and an Ethernet link layer header is additionally added. In such a message, there are two Ethernet link layer header information. In the network shown in Figure 1, an MPLS network connects three customer networks, and the IP routing protocol running in the three customer networks relies on IP addresses to find routes; while in the MPLS network, it relies entirely on MPLS labels to find routes. At this time, the label edge router (LER) at the edge of the MPLS network is responsible for establishing the corresponding relationship between the routing information based on the IP address and the routing information based on the MPLS label. In other words, on the ingress LER device, all client reports The text is marked with MPLS, and the previously added MPLS mark is removed on the egress LER device, and the label switching router (LSR) in the middle of the MPLS network only needs to switch according to the MPLS mark. The path from LER0 to LER1 via LSR in Figure 1 is called a label switching path (LSP). In Layer 2 VPN applications, MPLS is used as a bearer layer, which can encapsulate data frames of various networks.

这种二层VPN的特点在于提供服务的MPLS网络不关心用户的第三层即网络层信息，服务网络根据用户网络的第二层即链路层信息进行MPLS转发关系配置，用户网络的数据可以是以太网、点对点协议(PPP)、ATM、帧中继(FR)等，这样多种链路层的网络都可能借助MPLS实现链路层业务的传送。由于链路层的不同，其净荷类型也不同。而MPLS机制本身并不能区分，因此目前的做法是限定一条LSP中只能传送一种类型的净荷。在LSP静态配置方式下，需要人工指定该LSP承载的净荷类型；在LSP动态配置方式下，需要通过设备之间运行的路由协议和标记分发协议来协商确定某一条LSP承载的净荷类型。因此，在现有解决方案中存在如下不足：1.不同类型的净荷不能在同一条LSP中共存，因此需要消耗大量的LSP数目，且不易扩展；2.建立LSP前需要对业务类型进行协商，实现方式复杂，且需要网络中所有设备都运行相同协议才能协商成功，对设备的依赖性较高；3.当错误的将不同类型的净荷封装到同一条LSP中，MPLS无法对其类型进行识别，因此不具有纠错机制。The characteristic of this kind of Layer 2 VPN is that the MPLS network that provides the service does not care about the user's third layer, that is, the network layer information. The service network configures the MPLS forwarding relationship according to the second layer of the user network, that is, the link layer information. It is Ethernet, Point-to-Point Protocol (PPP), ATM, Frame Relay (FR), and so on. Such various link-layer networks may use MPLS to realize the transmission of link-layer services. Due to the difference in the link layer, its payload type is also different. However, the MPLS mechanism itself cannot distinguish, so the current practice is to limit that only one type of payload can be transmitted in one LSP. In the static LSP configuration mode, the payload type carried by the LSP needs to be manually specified; in the dynamic LSP configuration mode, the payload type carried by a certain LSP needs to be negotiated and determined through the routing protocol and label distribution protocol running between devices. Therefore, there are the following deficiencies in the existing solutions: 1. Different types of payloads cannot coexist in the same LSP, so a large number of LSPs need to be consumed, and it is not easy to expand; 2. Business types need to be negotiated before establishing an LSP , the implementation method is complex, and all devices in the network need to run the same protocol to negotiate successfully, which is highly dependent on the device; 3. When wrongly encapsulating different types of payloads into the same LSP, MPLS cannot match the type identification, so there is no error correction mechanism.

发明内容Contents of the invention

有鉴于此，本发明的目的在于：提供一种对MPLS网络中净荷类型进行识别的方法，应用该方法，能使一条LSP中承载多种类型的净荷。为实现上述目的，具体技术方案为：In view of this, the object of the present invention is to provide a method for identifying payload types in an MPLS network, and by using the method, multiple types of payloads can be carried in one LSP. In order to achieve the above purpose, the specific technical scheme is as follows:

A、入口标记边缘路由器根据从用户网络接收报文的接口类型，确定该报文的净荷类型，用一个类型编码表示该净荷类型，然后将该编码封装到MPLS报文中；A, the ingress marking edge router determines the payload type of the packet according to the interface type receiving the packet from the user network, represents the payload type with a type code, and then encapsulates the code into the MPLS packet;

B、出口标记边缘路由器接收到MPLS报文后，根据MPLS报文中的类型编码识别出净荷类型。B. After receiving the MPLS message, the egress-marked edge router recognizes the payload type according to the type code in the MPLS message.

所述步骤B之后，还可以进一步包括：根据该净荷类型，将所述的MPLS报文中的净荷转换为原用户网络对应的报文，并根据MPLS报文头的标签确定出接口，如果净荷类型和对应出接口的类型一致，则将该报文经由对应类型的接口发送至目标用户网络，如果净荷类型和对应出接口类型不一致，则不发送该报文并通知出口标记路由器的控制平面，以便控制平面进行进一步的处理来解决报文类型和接口类型不一致的问题。After the step B, it may further include: according to the payload type, converting the payload in the MPLS message into a message corresponding to the original user network, and determining the outgoing interface according to the label of the MPLS message header, If the payload type is consistent with the type of the corresponding outgoing interface, the message will be sent to the target user network through the corresponding type of interface, if the payload type is inconsistent with the corresponding outgoing interface type, the message will not be sent and the egress label router will be notified The control plane, so that the control plane can perform further processing to solve the problem of inconsistency between the packet type and the interface type.

标记边缘路由器都存有预设的报文类型编码表，该报文类型编码表存储了净荷类型与编码的对应关系。All marked edge routers store a preset packet type encoding table, which stores the correspondence between payload types and encodings.

步骤A中，入口标记边缘路由器根据来自用户网络的报文的净荷类型，通过查找所述报文类型编码表得到该类型对应的净荷类型编码；步骤B中，出口标记边缘路由器根据MPLS报文中的净荷类型编码，通过查找所述报文类型编码表得到该编码对应的净荷类型。In step A, the ingress marking edge router obtains the payload type encoding corresponding to the type by searching the message type encoding table according to the payload type of the message from the user network; For the payload type encoding in the text, the payload type corresponding to the encoding is obtained by searching the message type encoding table.

所述的报文类型编码表是人工指定的或由标准组织确定。The packet type encoding table is manually specified or determined by a standard organization.

步骤A中封装MPLS报文时，将类型编码存储在位于MPLS标记栈底部的控制字的保留位中；所述步骤B中，出口标记边缘路由器读取MPLS报文中上述的控制字，获得该报文的类型编码，由该类型编码得到对应的净荷类型。When encapsulating the MPLS message in step A, the type code is stored in the reserved bit of the control word positioned at the bottom of the MPLS label stack; in the step B, the egress label edge router reads the above-mentioned control word in the MPLS message to obtain the The type code of the message, and the corresponding payload type is obtained from the type code.

较佳地，该类型编码宽度为4比特。该类型编码的宽度可以根据实际情况进行相应的调整，可能小于4比特，也可能大于4比特。Preferably, the coding width of this type is 4 bits. The width of this type of encoding can be adjusted accordingly according to the actual situation, and may be less than 4 bits or greater than 4 bits.

或者采用以下替代方案：在所述标记边缘路由器中预设某一种净荷类型为默认类型，在封装MPLS报文时，在位于MPLS标记栈底部的控制字的保留位中选择一定宽度存储净荷类型指示码，所述步骤A为：入口标记边缘路由器根据接收到报文的接口类型识别出不同报文的净荷类型，若净荷类型为默认类型，则在净荷类型指示码中写入默认类型标识，若净荷类型不是默认类型，则入口标记边缘路由器在净荷类型指示码中写入非默认类型标识，在MPLS报文头部和净荷之间另外开辟一定字节宽度的净荷类型域存储净荷类型编码；Or adopt the following alternatives: preset a certain payload type in the label edge router as the default type, and select a certain width to store the payload in the reserved bit of the control word at the bottom of the MPLS label stack when encapsulating the MPLS message. Load type indicator code, the step A is: the ingress mark edge router recognizes the payload types of different messages according to the interface type of the received message, if the payload type is the default type, then write in the payload type indicator code Enter the default type identifier. If the payload type is not the default type, the ingress mark edge router will write the non-default type identifier in the payload type indicator code, and open a certain byte width between the MPLS packet header and the payload. The payload type field stores the payload type code;

较佳地，所述净荷类型指示码宽度为1比特，净荷类型编码宽度为2字节(即16比特)；该净荷类型指示码和类型编码的宽度可以根据实际情况分别进行相应的调整。Preferably, the width of the payload type indicator code is 1 bit, and the width of the payload type code is 2 bytes (i.e. 16 bits); Adjustment.

所述步骤B为：出口标记边缘路由器从MPLS报文中读取净荷类型指示码，如果指示码为默认类型标识，则将所述的MPLS报文中的净荷转换为默认类型的报文；The step B is: the egress mark edge router reads the payload type indicator code from the MPLS message, if the indicator code is the default type identification, then converts the payload in the MPLS message into a message of the default type ;

如果指示码为非默认类型标识，则出口标记边缘路由器读取净荷类型域中的类型编码，由该类型编码得到对应的净荷类型，并删除净荷类型域，再由MPLS报文头部标签确定对应的出接口类型，然后删除MPLS报文头，即将所述的MPLS报文中的净荷转换为原用户网络对应类型的报文。If the indicator code is a non-default type identifier, the egress marked edge router reads the type code in the payload type field, obtains the corresponding payload type from the type code, deletes the payload type field, and then uses the MPLS packet header The label determines the corresponding outgoing interface type, and then deletes the MPLS message header, that is, converts the payload in the MPLS message into a message of the corresponding type in the original user network.

如果指示码为默认类型标识，则在步骤B之后，增加如下步骤：将由转换得到的默认类型的净荷发送至默认类型的接口；If the indicator code is the default type identification, after step B, add the following steps: send the converted default type payload to the default type interface;

如果指示码为非默认类型，则在步骤B之后，增加如下步骤：对净荷类型和对应出接口类型的一致性进行校验，如果净荷类型和对应出接口的类型一致，则将该报文经由对应类型的接口发送至目标用户网络，如果净荷类型和对应接口类型不一致，则不发送该报文并通知出口标记路由器的控制平面，以便控制平面进行进一步的处理来解决报文类型和接口类型不一致的问题。If the indicator code is a non-default type, after step B, add the following steps: check the consistency between the payload type and the corresponding outgoing interface type, and if the payload type is consistent with the corresponding outgoing interface type, send the report The message is sent to the target user network through the interface of the corresponding type. If the payload type is inconsistent with the corresponding interface type, the message will not be sent and the control plane of the egress marking router will be notified, so that the control plane can perform further processing to resolve the difference between the message type and the corresponding interface type. The problem of inconsistent interface types.

根据本发明所提出的方法，出口端的标记边缘路由器根据从MPLS报文中提取出的类型编码，可以识别出该报文的净荷类型并进行相应的转发处理，因此一条LSP中能同时承载多种类型的报文。这样一来，在MPLS网络中LSP的数目大大减少，并且建立LSP前无需对每条LSP所承载的净荷类型专门进行协商，因此大大降低网络处理过程的复杂程度和网络内设备间的依赖程度。同时，由于本发明提出的方法对净荷类型进行自动识别，具备一定的纠错机制，降低了出现错误的可能性。According to the method proposed by the present invention, the label edge router at the egress can identify the payload type of the message according to the type code extracted from the MPLS message and perform corresponding forwarding processing, so one LSP can simultaneously carry multiple types of messages. In this way, the number of LSPs in the MPLS network is greatly reduced, and there is no need to negotiate the payload type carried by each LSP before establishing an LSP, thus greatly reducing the complexity of network processing and the degree of dependence between devices in the network . At the same time, since the method proposed by the invention automatically identifies the payload type, it has a certain error correction mechanism, which reduces the possibility of errors.

附图说明Description of drawings

图1所示为基于MPLS的二层VPN的应用网络示意图；Figure 1 shows a schematic diagram of an application network based on MPLS-based Layer 2 VPN;

图2为MPLS二层VPN封装以太网数据帧格式示意图；Fig. 2 is a schematic diagram of the MPLS two-layer VPN encapsulation Ethernet data frame format;

图3所示为本发明实施例一在PWE3中通过控制字直接指示净荷类型的MPLS报文示意图；FIG. 3 is a schematic diagram of an MPLS message directly indicating a payload type through a control word in PWE3 according to Embodiment 1 of the present invention;

图4所示为本发明实施例一在PWE3中通过控制字直接指示净荷类型的MPLS报文工作流程图；Fig. 4 shows that embodiment 1 of the present invention is in PWE3 directly indicates the MPLS message working flow chart of payload type through control word;

图5所示为本发明实施例二在PWE3中通过控制字间接指示净荷类型的MPLS报文示意图；FIG. 5 is a schematic diagram of an MPLS message indirectly indicating a payload type through a control word in PWE3 in Embodiment 2 of the present invention;

图6所示为本发明实施例二在PWE3中通过控制字间接指示净荷类型的MPLS报文工作流程图。FIG. 6 is a flow chart of the MPLS message in which the payload type is indirectly indicated through the control word in the PWE3 according to Embodiment 2 of the present invention.

具体实施方式Detailed ways

为使本发明的目的、技术方案和优点更加清楚，下面结合具体实施例对本发明作进一步地详细说明。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific examples.

英特网工程任务组(IETF)定义的端到端伪线仿真(PWE3)，被认为是二层VPN将最可能采用的封装协议。使用PWE3机制，运营商可以将所有的传送业务转移到一个融合的网络(如IP/MPLS)之中。从用户的角度来看，可以认为PWE3模拟的虚拟线是一种专用的链路或电路。在PWE3技术里，在MPLS标记栈的底部增加一个32比特的控制字CW，其中有12比特的保留位。本发明的关键就是利用这12比特的保留位，在MPLS网络入口处利用该保留位记录报文净荷的类型，在MPLS网络出口处根据保留位中的记录确定报文净荷的类型。The end-to-end pseudowire emulation (PWE3) defined by the Internet Engineering Task Force (IETF) is considered to be the most likely encapsulation protocol that Layer 2 VPN will adopt. Using the PWE3 mechanism, operators can transfer all transmission services to a converged network (such as IP/MPLS). From the user's point of view, it can be considered that the virtual wire simulated by PWE3 is a dedicated link or circuit. In the PWE3 technology, a 32-bit control word CW is added at the bottom of the MPLS label stack, including 12 reserved bits. The key of the present invention is to use the 12-bit reserved bits to record the type of the message payload at the entrance of the MPLS network, and determine the type of the message payload at the exit of the MPLS network according to the records in the reserved bits.

以下举两个技术实施例进行详细说明。其中实施例一通过控制字的保留位直接指示净荷类型。其MPLS报文示意图如图3所示，本实施例中将保留位中的4比特作为填写标识净荷类型的类型编码的位置，而该字节长度也可根据实际需要进行调整。MPLS网络入口端设备根据识别出来的净荷类型填写对应的类型编码，出口端设备在根据该类型编码识别和校验净荷类型。工作流程的具体步骤如图4所示：Two technical embodiments are given below to describe in detail. In the first embodiment, the payload type is directly indicated through the reserved bits of the control word. The schematic diagram of its MPLS message is shown in Figure 3. In this embodiment, 4 bits in the reserved bits are used as the position for filling in the type code identifying the payload type, and the byte length can also be adjusted according to actual needs. The ingress device of the MPLS network fills in the corresponding type code according to the identified payload type, and the egress device identifies and verifies the payload type according to the type code. The specific steps of the workflow are shown in Figure 4:

步骤401：从MPLS入口端标记边缘路由器LER0到出口端标记边缘路由器LER1建立一条标记交换路径LSP；Step 401: Establish a label switching path LSP from the MPLS ingress label edge router LER0 to the egress label edge router LER1;

步骤402～步骤403：在MPLS网络的入口端，来自用户网络的报文经由入口端标记边缘路由器LER0的对应类型接口接入LER0，这些接口可能是以太网、PPP、ATM或FR等类型。每种接口传输与之对应的特定净荷类型的报文。LER0根据传送报文的接口的类型识别出该报文的净荷类型，并在将净荷封装到MPLS报文中的同时，通过查找一个预设的报文类型编码表确定该净荷类型对应的类型编码并将该类型编码填入控制字CW保留位中规定的位置。该报文类型编码表如表1所示：净荷类型类型编码以太网 0 PPP 1 ATM 2 FR 3 ...... ...... Steps 402 to 403: At the ingress of the MPLS network, packets from the user network are connected to LER0 through corresponding interfaces of the ingress labeled edge router LER0. These interfaces may be Ethernet, PPP, ATM or FR. Each interface transmits packets of a specific payload type corresponding to it. LER0 identifies the payload type of the message according to the type of the interface that transmits the message, and at the same time encapsulates the payload into the MPLS message, and determines the corresponding payload type by searching a preset message type encoding table. The type code and fill the type code into the position specified in the reserved bit of the control word CW. The packet type encoding table is shown in Table 1: payload type type encoding ethernet 0 PPP 1 ATMs 2 FR 3 … …

表1 Table 1

若净荷类型编码占用的比特数为n，则该表中右边一列是0至2ⁿ-1的数字或其中一部分数字的任意的一种排列。本实施例中，净荷类型编码占用的比特数为4，则净荷类型编码表中右边一列是0至15或其中一部分数字的任意一种排列。其内容可以由人工配置或者由标准组织建立的标准来规定。If the number of bits occupied by the payload type encoding is n, the right column in the table is any arrangement of numbers from 0 to 2 ⁿ -1 or some of them. In this embodiment, the number of bits occupied by the payload type encoding is 4, and the right column in the payload type encoding table is any arrangement of 0 to 15 or a part thereof. Its content can be manually configured or specified by standards established by standards organizations.

步骤404：MPLS报文在MPLS网络经由标记交换路径LSP发送到出口端LER1；Step 404: The MPLS message is sent to the egress port LER1 via the label switching path LSP on the MPLS network;

步骤405：当出口端LER1收到一个MPLS报文时，根据报文中控制字CW的保留位中写入的类型编码，通过查找内容与表1完全相同的一个报文类型编码表来找到该编码对应的净荷类型。该查找过程以类型编码为索引，查找的结果是净荷类型。出口端LER1根据MPLS报文头部标签选择对应类型的出接口。出口端LER1将MPLS标记除去，即将MPLS报文中的净荷转换为对应类型的报文，并对净荷类型和对应的出接口类型的一致性进行校验。Step 405: When the egress port LER1 receives an MPLS message, according to the type code written in the reserved bit of the control word CW in the message, find the message type code table by searching a message type code table whose content is exactly the same as that in Table 1. Encode the corresponding payload type. The search process uses the type code as an index, and the result of the search is the payload type. The egress end LER1 selects the corresponding type of egress interface according to the MPLS packet header label. The egress end LER1 removes the MPLS label, that is, converts the payload in the MPLS packet into a corresponding type of packet, and checks the consistency between the payload type and the corresponding outgoing interface type.

步骤406～步骤407：如果净荷类型和出口端LER1的接口类型一致，则将报文经由LER1对应的接口发送到用户网络，否则不发送，同时通知控制平面，控制平面可以据此进行进一步处理来解决净荷类型和接口不一致的问题。Step 406-Step 407: If the payload type is consistent with the interface type of the egress port LER1, then send the message to the user network via the interface corresponding to LER1, otherwise not send, and notify the control plane at the same time, and the control plane can further process accordingly To solve the problem of inconsistent payload type and interface.

以上实施例是采用控制字的保留位直接指示净荷类型的方法，以下的实施例二则是用控制字间接指示净荷类型。MPLS报文的示意图如图5所示，在控制字保留位中采用一个1比特的净荷类型指示域来指示MPLS报文头和净荷之间是否还有另外一个2字节的净荷类型域来存储净荷类型编码。具体操作步骤如图6所示：The above embodiment uses the reserved bit of the control word to directly indicate the payload type, and the second embodiment below uses the control word to indirectly indicate the payload type. The schematic diagram of the MPLS message is shown in Figure 5. A 1-bit payload type indication field is used in the reserved bit of the control word to indicate whether there is another 2-byte payload type between the MPLS message header and the payload. field to store the payload type encoding. The specific operation steps are shown in Figure 6:

步骤601：从MPLS入口端标记边缘路由器LER0到出口端标记边缘路由器建立一条标记交换路径LSP，并指定一种类型的净荷为该LSP的默认类型；Step 601: Establish a label switching path LSP from the MPLS ingress label edge router LER0 to the egress label edge router, and specify a type of payload as the default type of the LSP;

步骤602-步骤605：在MPLS网络的入口端，LER0根据接口的类型识别出报文的净荷类型，如果该净荷为默认类型，则在净荷类型指示域中填入0；如果该净荷不是默认净荷，则在净荷类型指示域中填入1，在MPLS报文的净荷和MPLS报文头之间开辟一个2字节的净荷类型域；通过查找类型编码表，在净荷类型域中写入该净荷类型对应的类型编码；Step 602-Step 605: At the ingress port of the MPLS network, LER0 identifies the payload type of the message according to the type of the interface, if the payload is the default type, then fill in 0 in the payload type indication field; if the payload type If the payload is not the default payload, fill in 1 in the payload type indication field, and open up a 2-byte payload type field between the payload of the MPLS message and the MPLS message header; by looking up the type encoding table, in Write the type code corresponding to the payload type in the payload type field;

步骤606：MPLS报文在MPLS网络中通过LSR转发，最后到达出口端；Step 606: The MPLS message is forwarded through the LSR in the MPLS network, and finally reaches the egress port;

步骤607-步骤612：当出口端LER1收到一个MPLS报文时，读取净荷类型指示域中的内容，如果是0，则除去MPLS标记后直接按照默认类型将净荷转发到默认接口；如果是1，再读取净荷类型域的类型编码，通过检索类型编码表得到该净荷的类型，并删除该净荷类型域。接着先除去MPLS标记，将净荷转换为对应类型的报文，出口端LER1根据MPLS报文头部标签选择对应类型的出接口，再对净荷类型和对应出接口类型的一致性进行校验，如果净荷类型和接口类型一致，则将报文经由LER1对应的接口发送到用户网络，否则不发送，同时通知控制平面，控制平面可以据此进行进一步处理来解决净荷类型和接口不一致的问题。Step 607-step 612: When the egress port LER1 receives an MPLS message, read the content in the payload type indication field, if it is 0, then remove the MPLS mark and directly forward the payload to the default interface according to the default type; If it is 1, then read the type code of the payload type field, obtain the type of the payload by retrieving the type code table, and delete the payload type field. Then remove the MPLS label first, convert the payload into the corresponding type of message, the egress port LER1 selects the corresponding type of outbound interface according to the MPLS message header label, and then checks the consistency between the payload type and the corresponding outbound interface type , if the payload type is consistent with the interface type, the message will be sent to the user network via the interface corresponding to LER1, otherwise it will not be sent, and the control plane will be notified at the same time, and the control plane can further process accordingly to resolve the inconsistency between the payload type and the interface question.

这种替代方案比较适合在MPLS网络中，某一种净荷类型的业务量相对其他类型较大的情况。This alternative solution is more suitable for the case where the service volume of a certain type of payload is relatively large compared with other types in the MPLS network.

值得注意的是，以上所举实施例中，其中类型编码在控制字中的位置和宽度包括但不限于上述描述。以上实施例虽然是以MPLS网络二层VPN中采用PWE3技术的应用为例，但本发明所述的处理方法与具体的封装协议无关，只要是基于MPLS网络的二层VPN都可适用。It should be noted that, in the above-mentioned embodiments, the position and width of the type code in the control word include but are not limited to the above description. Although the above embodiments are based on the application of PWE3 technology in Layer 2 VPN of MPLS network as an example, the processing method described in the present invention has nothing to do with the specific encapsulation protocol, as long as it is based on Layer 2 VPN of MPLS network, it is applicable.

Claims

1, a kind of method that load type is identified in multi-protocol label switching MPLS network, it is characterized in that, this method comprises the following steps:

A, the ingress marking edge router determines the payload type corresponding to the packet according to the interface type receiving the packet from the user network, represents the payload type with a type code, and then encapsulates the code into the MPLS packet;

B. After receiving the MPLS message, the edge router with the egress label recognizes the corresponding payload type according to the type code in the MPLS message.

2. The method according to claim 1, characterized in that, after the step B, the following steps are added: converting the payload in the MPLS message into a message corresponding to the original user network, and according to the MPLS The label in the packet header determines the outgoing interface. If the payload type is consistent with the corresponding outgoing interface type, the packet will be sent to the target user network via the corresponding type of interface. If the payload type is inconsistent with the corresponding outgoing interface type, the Send this message and notify the control plane of the egress tagged edge router.

3. The method according to claim 1, wherein the tag edge routers all store a preset packet type coding table, and the packet type coding table stores the correspondence between payload types and codes.

4. The method according to claim 3, wherein in step A, the ingress label edge router obtains the payload type corresponding to the packet type by searching the packet type encoding table according to the payload type of the packet from the user network. load type code;

In step B, the egress label edge router obtains the payload type corresponding to the code by looking up the message type code table according to the payload type code in the MPLS message.

5. The method according to claim 3, characterized in that said message type encoding table is manually specified or determined by a standard organization.

6. The method according to claim 1, 2, 3, 4 or 5, characterized in that, when encapsulating the MPLS message in step A, the type code is stored in the reserved bit of the control word at the bottom of the MPLS label stack;

In the step B, the egress marking edge router reads the above-mentioned control word in the MPLS message, obtains the type code of the message, and obtains the corresponding payload type from the type code.

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

8. The method according to claim 1, 3, 4 or 5, characterized in that a certain payload type is preset as the default type in the label edge router, and when encapsulating MPLS packets, the Select a certain width to store the payload type indicator code in the reserved bit of the control word at the bottom of the mark stack,

The step A is: the ingress mark edge router recognizes the payload types of different messages according to the interface type of the received message, if the payload type is the default type, then write the default type identifier in the payload type indicator code, If the payload type is not the default type, the ingress mark edge router writes the non-default type identifier in the payload type indicator code, and additionally opens up a payload type field storage with a certain byte width between the MPLS packet header and the payload payload type encoding;

The step B is: the egress mark edge router reads the payload type indicator code from the MPLS message, if the indicator code is the default type identification, then converts the payload in the MPLS message into a message of the default type ;

If the indicator code is a non-default type identifier, the egress marked edge router reads the type code in the payload type field, obtains the corresponding payload type from the type code, deletes the payload type field, and then uses the MPLS packet header The label determines the corresponding outgoing interface, and then deletes the MPLS message header, that is, converts the payload in the MPLS message into a message of the corresponding type in the original user network.

9. The method according to claim 8, wherein if the indicator code is a default type identifier, after step B, the following steps are added: sending the converted payload of the default type to the interface of the default type;

If the indicator code is a non-default type, after step B, add the following steps: check the consistency between the payload type and the corresponding outgoing interface type, and if the payload type is consistent with the corresponding outgoing interface type, send the report The message is sent to the target user network through the interface of the corresponding type. If the payload type is inconsistent with the corresponding interface type, the message is not sent and the control plane of the egress router is notified;

10. The method according to claim 8, wherein the width of the payload type indicator code is 1 bit, and the width of the payload type code is 2 bytes.