CN102387070A - Data protection method for T-MPLS (transport multi-protocol switching) shared protection ring before failure recovery - Google Patents

Abstract

The invention discloses a data protection method before recovery of a T-MPLS shared protection ring. The T-MPLS shared protection ring includes an initial node for sending data and a destination node for receiving data. The nodes at both ends of the faulty path are the former node and the back node, before the failure occurs, the front node transmits data to the back node; the data protection method includes: the data sent by the start node is divided into two types of TDM data and non-TDM data, and after the failure occurs, the start node The last frame of data sent is marked, then the TDM data is cached, and the non-TDM data is transmitted to the destination node in the opposite direction; at this time, the data sent by the starting node is loopback protected, and then switched to source routing protection after the end. The invention combines the advantages of the loopback protection mode and the source routing protection mode, adopts the loopback protection mode for the data sent by the starting node, and adopts a method of different treatment for the data of the source node, which improves the recovery speed of the fault and reduces the risk of failure. Small packet loss rate.

Description

Data Protection Method Before T-MPLS Shared Protection Ring Fault Recovery

technical field

The invention relates to the technical field of network communication, in particular to a data protection method before recovery of a fault in a T-MPLS shared protection ring.

Background technique

With the IP-based telecommunication services, the services carried by the transport network are changing from time-division multiplexing (TDM,) to IP-based, and the Synchronous Digital Hierarchy (SDH)-oriented TMD service transport network technology has been difficult to adapt to the needs of services. Transmission requirements, the existing Ethernet technology cannot meet the transmission requirements well, and the multi-protocol label switching technology (MPLS) is also beyond its capabilities. In order to adapt to carrier-class service transmission, carrier-class operation, management and maintenance (OAM) and protection, connection-oriented packet transport network technology is required, which will also be the development trend of packet transport network technology in the future.

With the emergence of a large number of new services on the transmission network and the rapid expansion of the network scale, the convergence trend of the communication industry is becoming more and more prominent. Among them, on the basis of the original network, the development has higher speed, more reliable survivability, and higher Packet transport network with better performance, more flexible control and management capabilities is the main direction of development, as one of the key technologies of next-generation PTN, transport multi-protocol switching (T-MLPS) combines the characteristics of circuit transport network and packet transport network . It has a good development prospect, so how to improve its reliability and management and maintenance has become a research hotspot, especially how to recover when the network fails, and how to reduce the data loss during the recovery process. package etc.

T-MPLS is a key technology of PTN. T-MPLS is a connection-oriented packet transmission technology developed on the basis of MPLS. T-MPLS simplifies and transforms MPLS technology. Switching and OAM functions, it has the common core technical features of PTN technology, namely the lowest transmission cost per T-MPLS bit, multi-service support based on packet services, determinable quality of service, powerful OAM management mechanism and network management capabilities, etc. Compared with MPLS technology, T-MPLS eliminates unnecessary IP-oriented processing, which effectively reduces costs for operators; it has complete service expansion capabilities and supports the transmission of different signals. At the same time, it is also in line with the trend of network transformation. It is connection-oriented and has a higher survivability than traditional networks; it can use a common control plane to ensure interconnection and interworking with the current transport network.

The ring network protection modes of T-MPLS mainly include two modes: linear protection, switchover and shared protection ring. Shared protection ring (T-MPLS Shared Protection Ring, TM-SPRing) is a ring network constructed by logical structure of T-MPLS LSP transmission. Adjacent nodes are bidirectionally connected, which can be a physical connection or a logical connection. connection relationship. The transmission channel entity used to transmit services between ring network nodes is implemented based on a group of LSPs based on T-MPLS. The protection of TM-SPRing is aimed at adjacent node segments. In order to prevent adjacent node segments from failing, In the case of TM-SPRing, in order to realize fast data protection, the following two protection mechanisms are formulated, source routing (Steering) mode and loopback (Wrapping) mode.

The Wrapping protection mode is that when a node on the network detects a network failure, the adjacent node on the fault side sends a switching request to the adjacent node through the APS protocol. When a node detects a failure or receives a switching request, the services forwarded to the failed node will go in another direction.

As shown in Figure 1, when the network is working normally, the path from node A to node D, assuming that the path between node C and node D in the network fails, the Wrapping protection mode is that the data bypasses the faulty node, as shown in Figure 2, at this time The service signal returns from node C, passes through node B, node A, node G, node F, node E, and finally reaches node D. Through the loopback path method, the business data finds a suitable path again. The disadvantage of using this Wrapping protection method to deal with network faults is that due to the loopback of faulty nodes, paths will be increased, and the routed path is not an optimal path.

Steering protection means that when the network detects a network failure, all nodes on the ring send switching requests through the APS protocol. Each source node of a point-to-point connection performs switching, and all T-MPLS connections affected by network failure are switched from the working direction to the protection direction. When the network fails or the APS protocol disappears, all affected services return to the original path . As shown in Figure 3, when the network detects a failure between node C and node D, the data from node A is no longer sent to node D via node B and node C, but is directly switched to another path. The disadvantage of this switching method is that the packet loss rate is high.

Contents of the invention

The invention provides a data protection method before recovery of a fault in a T-MPLS shared protection ring, which solves the problems of long paths in the traditional Wrapping protection mode and high packet loss rate in the Steering protection mode.

A data protection method before recovery of a T-MPLS shared protection ring failure, the T-MPLS shared protection ring includes a starting node for sending data and a destination node for receiving data, and the nodes at both ends of the faulty path are the front node and the back node respectively , before the fault occurs, the front node transmits data to the back node; the data protection method includes:

The originating node divides the sent data into TDM data and non-TDM data. After a fault occurs, the originating node marks the last frame of data sent, then caches the TDM data and transmits the non-TDM data in the opposite direction to Destination node (this mechanism does not affect the transmission of non-TDM data, which improves the efficiency of non-TDM business data transmission); the former node transmits the received data to the destination node in a loopback mode. During this process, when the initial When a node receives its own marked data frame, it transmits the cached TDM data and newly received data to the destination node in the opposite direction;

The reverse direction is the direction opposite to the direction of data transmission between the originating node and the destination node before the fault occurs.

After the originating node receives the data marked by itself, the data it transmits includes buffered TDM data, newly received TDM data and non-TDM data.

Preferably, the previous node marks the received first frame of data sent by the starting node before the fault occurs, thus.

The present invention combines the advantages of the loopback protection mode and the source routing protection mode, adopts the loopback protection mode for the data sent by the starting node, reduces packet loss, and adopts the Source routing mode protection optimizes the transmission path.

Description of drawings

Figure 1 is a schematic diagram of data flow from node A to node D during normal operation;

Fig. 2 Schematic diagram of Wrapping protection mode when node C and node D fail;

Fig. 3 Schematic diagram of Steering protection mode when node C and node D fail;

Fig. 4 is a schematic diagram of a structure of a protection request frame.

Fig. 5 is a flow chart of switching from Wrapping protection to Steering protection in the present invention.

Detailed ways

As shown in Figure 1, the T-MPLS shared protection ring is composed of seven nodes A~G, and two-way communication can be realized between two adjacent nodes. The management and maintenance module of the communication system periodically detects the connection status of the ring network, which can be in the form of connectivity detection and loopback detection.

If no fault is detected, it means that the network is in a normal working state and enters the next detection cycle. If a fault is detected, it means that the loop is disconnected. Notify the relevant nodes of the switchover information, and communicate with another faulty node to complete the switchover in the loopback mode.

As shown in Figure 2, the path of data transmission at this time is Node A-Node B-Node C-Node D. When a fault occurs between Node C and Node D, Node C and Node D start to send protection request frames, and the The automatic switching information notifies the relevant nodes, and at the same time, node C marks the first frame of the data sent by node A before the failure. The marking method is to mark the reserved bytes of the received data frame.

As shown in Figure 4, the data frame generally includes the function type, label header, reserved bytes, and data information. The last two bytes of the reserved bytes of the first frame of data received by node C after the failure occurs Set it to "01", and at the same time transmit the data after the failure to node D in a loopback mode. The transmission path is node C-node B-node A-node G-node F-node E-node D. It can be seen that These data will route to node A.

The transmission of the protection request frame is generally transmitted from the node to the next node, and its content field contains the ID of the starting node and the ID of the destination node. After the next node receives the protection request frame, it will compare it with its own ID. If not The originating node or the destination node will transmit the protection request frame until the originating node receives the request frame and stops transmitting to the next node.

When the initiating node receives the protection request frame, the initiating node divides the sent data into two categories, among which the TDM data is buffered and the transmission is suspended, while the non-TDM data continues to be transmitted to node D in the opposite direction, and the transmitted The last frame of data is marked, and the marking method is to set the last two bits of the reserved byte to "11".

As shown in Figure 3, when node A receives the first frame of data marked by node C, it starts to prepare to switch the protection mode, because at this time it indicates that the last frame of data marked by it will also arrive, until node A receives the data marked by it In the last frame of data, node A transmits the cached TDM data and newly received data to node D in the opposite direction, and switches to the source routing protection mode.

Claims (2)

1. A data protection method before recovery of a T-MPLS shared protection ring failure, the T-MPLS shared protection ring includes a starting node for sending data and a destination node for receiving data, and the nodes at both ends of the faulty path are respectively previous nodes and The rear node, before the fault occurs, the front node transmits data to the rear node; the data protection method includes: The originating node divides the sent data into TDM data and non-TDM data. After a fault occurs, the originating node marks the last frame of data sent, then caches the TDM data and transmits the non-TDM data in the opposite direction to Destination node; the previous node transmits the received data to the destination node in a loopback mode. In the process, when the starting node receives the data frame marked by itself, it will cache the TDM data and the newly received data along the Transmit in the opposite direction to the destination node. 2. The data protection method according to claim 1, wherein the previous node marks the received first frame of data sent by the starting node before the fault occurs.

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