Method for avoiding message loop

A loop and message technology, applied in the field of virtual private network, can solve problems such as LDPrequest message loop, and achieve the effect of improving operating efficiency

CN1874290AActive Publication Date: 2006-12-06HUAWEI TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2006-12-06

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Abstract

The method is designed for use in a network with multi multi-jumping pseudo wire switch nodes, and comprises the following steps: each multi-jumping pseudo wire switch node sends a label request message carrying loop detection data to a multi-jumping pseudo wire switch node at next jumping; according to the loop detection data, each multi-jumping switch node decides if a message loop is generated in order to determine the label request message discarded at the time of generating the message loop. The invention can avoid forming loop of label request message between switch nodes caused by improper configuration in multi-jumping condition, when networking of PWE3 network is applied.
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Description

technical field

[0001] The invention relates to virtual private network technology in the field of data communication, more specifically, to a method for preventing message loops. Background technique

[0002] As a traditional business of telecom operators, leased lines can provide enterprises with Layer 2 link communication networks, but they have disadvantages such as high construction costs, long cycle times, inability to share lines, and difficult management, making them unsuitable for enterprise users The characteristics of many branches and fast increase, therefore, with the development of ATM (Asynchronous Transfer Mode, abbreviation for Asynchronous Transport Mode) and Frame Relay (Frame Relay, hereinafter abbreviated as FR) technology, telecom operators began to use virtual circuits (Virtual Circuits) Circuit) way to provide customers with point-to-point layer-2 connection services, on which the enterprise builds its own layer-3 network to carry IP (Internet Protoco...

Examples

Embodiment 1

[0046] Under multi-hop environment, utilize the first embodiment of the inventive method exactly, comprise the IP address of the S-PE that message passes through in the LDP Request message exactly, its IP address uses pseudowire switching node type length value structure (PWswitching point TLV) Record. The data structure details of PW switching point TLV are as follows:

[0047] 0 1 2 3

[0048] 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

[0049] +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

[0050] |1|0| PW sw TLV (0x096B) | PW sw TLV Length |

[0051] +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

[0052] | Type | Length | Variable Length Value |

[0053] +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

[0054] | Variable Length Value |

[0055] | ″ |

[0056] +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

[0057] in:

[0058] -PW sw TLV Length, spe...

Embodiment 2

[0074] By applying the method provided by the present invention, a new data type definition can be added to PW switching point TLV, and its type code can be assigned by IANA, assuming 0x04, which is used to record the number of S-PEs passed by the LDP Request message. . The new data structure is defined as follows

[0075] Type Length Description

[0076]0x04 1 Hop Count of PW Switching Point traversed

[0077] The steps of detecting message loop in embodiment 2 are as follows:

[0078] 1. When the S-PE sends an LDP request message, it adds 1 to the count in the PW switching point TLV;

[0079] 2. When the S-PE receives the LDP request message, it checks whether the count in the PW switching pointTLV reaches the configured maximum value;

[0080] 3. If it reaches the maximum value, it means that a loop occurs, and the S-PE immediately discards the LDP request message. Otherwise, continue processing the message.

[0081] Wherein, the setting of the maximum value of the al...

Embodiment 3

[0083] Embodiment 3 is by carrying the message of PW switching point TLV, in the multi-hop environment, the expected survival time is automatically counted down, and the countdown result is stored in the countdown unit, which is our PW switching The definition of a new data type TTL (time to live) added to the point TLV, its type code can be assigned by IANA, assuming it is 0x05, and the length is 1, which is used to record the time to live of the LDPRequest message. The specific description is as follows:

[0084] Type Length Description

[0085] 0x05 1 TTL (Time To Live) field value

[0086] In embodiment 3, the steps of detecting whether there is a message loop in a multi-hop environment are as follows:

[0087] 1. When the LDP request message is sent for the first time, the originating S-PE sets an initial value greater than 0 in the countdown unit;

[0088] 2. When any S-PE receives the LDP request message, it first judges whether the data value of the countdown counte...