WO2006042472A1

WO2006042472A1 - A method for implementing fair transmission of flow in the mpls ring network

Info

Publication number: WO2006042472A1
Application number: PCT/CN2005/001723
Authority: WO
Inventors: Yuli Shi; Huaixue Wan; Xingyue Quan; Yang Yang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-10-20
Filing date: 2005-10-20
Publication date: 2006-04-27
Also published as: CN1764149A; CN100387025C

Abstract

A method for implementing fair transmission of flow in the MPLS ring network, includes: firstly, determine best-effort service messages according to the information carried in the MPLS messages; then, calculate the fair bandwidth that said messages can occupy using the fair algorithm, and transmit the messages based on said fair bandwidth in the MPLS ring network. Therefore, the present invention can firstly identify corresponding best-effort services on the node of the MPLS ring network, then, allocate bandwidth that said best-effort services can occupy using the fair algorithm fairly, so that ensure that each best-effort service transmitted by each network node in the MPLS ring network can fairly occupy the remainder bandwidth resource of high priority level services effectively.

Description

Method for realizing fair transmission of traffic in MPLS ring network

The present invention relates to the field of multi-protocol label switching (MPLS) technology, and in particular, to a method for implementing fair delivery of traffic in an MPLS ring network. Background of the invention

The Multi-Service Transport Node (MSTP) based on the Synchronous Digital Sequence (SDH) system can well support Time Division Multiplexing (TDM) voice services and Digital Data Network (DDN) leased line services, but the support for IP packet services is poor. The uncertainty and unpredictability of IP traffic itself makes the use of traditional SDH equipment to provide IP packet transmission services with lack of bandwidth dynamic adjustment capability, low resource utilization, poor network scalability, complex equipment implementation, and weak topology management capabilities. And so on.

Ethernet technology can support IP packet services very well. It is characterized by simplicity, easy expansion, and low price. It has been widely used in LAN and metropolitan area networks. However, Ethernet technology does not meet the reliability and scalability requirements of metropolitan area networks due to the lack of carrier-class quality of service (QoS), network fast protection, recovery, and sophisticated operation and management (OAM). Correspondingly, the automatic discovery of the media access control (MAC) layer topology is slow and inefficient.

Resilient Packet Network (RPR) technology combines the advantages of Ethernet technology, Asynchronous Transfer Mode (ATM) technology, and SDH technology. Through the fair algorithm, the reuse problem of bandwidth between sites is well solved; the protection of loopback (Wrapping) and source routing (Steering) is provided, and the protection time is limited to 50ms; at the same time, high, medium and low are provided. A differentiated service with business priorities and a relatively complete OAM function is a more economical metro (MAN) solution. However, with the continuous development of information network technology and the rapid spread of the Internet, the concept of Next Generation Network (NGN) transport network has gradually formed, and the types, formats, and service requirements of network information flows have become increasingly rich, by SDH, asynchronous. The data transmission networks dominated by transmission mode (ATM), MSTP, and wavelength division multiplexing (WDM) technology are gradually becoming inadequate in handling the scheduling and exchange of transport layer services. NGN transport layer networks urgently need to be able to uniformly carry multiple services. A type of transport ring network technology that provides better QoS, is suitable for MAN and wide area network (WAN) applications, and is flexible and low-cost. To this end, the corresponding MPLS ring network technology has emerged.

Congestion is a common phenomenon in communication systems, but in the existing MPLS ring network technology, there is no control for congestion.

In the service node of the MPLS ring network, when the bandwidth of the high-priority service available in the link is as good as possible, the remaining bandwidth of the service is less than the total bandwidth of the best-effort service, so that when congestion occurs, if multiple best-effort transmissions are transmitted, Trying to transmit the characteristics of the service itself to preempt the bandwidth will cause some of the bandwidth that the best-effort transmission service can occupy, while other efforts to transmit the service can only occupy the remaining bandwidth required by itself, resulting in the node trying to transmit the service. Unfair transmission. Further, in the case of congestion, due to unfair transmission, it is often the case that one or several of the best efforts to transmit the traffic cannot be transmitted. In the communication network, the general service shield does not require the best-effort service, but if a best-effort service fails to transmit at a certain node, it is unbearable for the user.

This is illustrated below by a specific example.

As shown in FIG. 1, the three nodes S1, S2, and S3 all transmit traffic to the node S4. Assume that the total bandwidth of the link is 10M. As shown in Figure 2, node S1 sends 6M service, node S2 sends 5M service, node S3 sends 2M service, and the service is trying to transmit service. Bandwidth characteristics, on the S2 node, the 5M service to be sent by the S2 node is only Can get 4M bandwidth. On the S3 node, since the total bandwidth of the link 10M has been completely preempted by the services sent by the S1 node and the S2 node, and no bandwidth is allocated to the 2M service to be sent by the node, the 2M service cannot be sent to the S4. It can be seen from the above example that the unfair transmission phenomenon of the best-effort transmission service occurs in the S2 and S3 nodes where congestion occurs, and the phenomenon that the traffic of the 2M service to be transmitted cannot be transmitted to the S4 at the S3 node. Summary of the invention

In view of the above problems in the prior art, an object of the present invention is to provide a method for implementing fair delivery of traffic in an MPLS ring network, which can implement fair transmission of best effort transmission services in an MPLS ring network.

The object of the invention is achieved by the following technical solutions:

The present invention provides a method for implementing fair delivery of traffic in an MPLS ring network, including:

A. Determine, according to the information carried in the MPLS packet, a packet that attempts to transmit the service;

B. Determine the fair bandwidth that the packet that is trying to transmit the service can occupy, and try to transmit the service packet based on the fair bandwidth in the MPLS ring network.

The information carried in the MPLS packet may be: a service transmission value set in an EXP field of an experimental domain in an MPLS packet;

Then step A is:

When the service transmission value carried in the EXP field of the packet received by the MPLS ring network node is smaller than a preset threshold, it is determined that the packet is a packet that tries to transmit the service.

The information carried in the MPLS packet may also be: a best-effort service flag set in the best-effort service packet;

Then step A is:

When the received message carries the best effort service flag, it is determined that the message is exhausted. Force to transmit business messages.

Preferably, said best effort delivery service flag is set in a fixed bit of the message EXP field. The information carried in the MPLS packet may also be: an LSP label value;

Then step A is:

When the label exchange path LSP label value of the received packet is a pre-configured dedicated label value of the LSP transmitting the best effort transmission service, it is determined that the message is a best effort transmission service message.

The information carried in the MPLS packet may also be: an LSP label value and a service transmission value set in an EXP field of the packet;

Then step A is:

When the service transmission value carried in the EXP field of the received packet is smaller than a threshold corresponding to the LSP label value of the packet, it is determined that the packet is a packet that tries to transmit the service.

Preferably, the step B may include:

Bl. Calculate the fair rate of the best-effort transmission service by using a fairness algorithm on the MPLS ring network node where the traffic jam occurs;

B2, adjusting the bandwidth of the best-effort service of the local upper ring according to the calculated fair rate, and transmitting the calculated fair rate to the upstream ring network node;

B3. The upstream ring network node that knows the fair rate adjusts the bandwidth of the corresponding best-effort service based on the fair rate, and transmits the best-effort service packet according to the bandwidth.

Further, the step B2 may include:

The hop count of the packet being forwarded and the identifier of the MPLS ring network node are sent to the upstream ring network node together with the fair rate.

Preferably, the information sent to the upstream ring network node is carried by the flow control message. Preferably, the information sent to the upstream ring network node is transmitted through an LSP channel that transmits control information. Preferably, in the step B3, the upstream ring network node that knows the fair rate adjusts the bandwidth of the corresponding best effort service packet based on the fair rate:

B31. The upstream ring network node calculates, by using a fairness algorithm, a fair rate of the best-effort transmission service according to the received information.

B32. The upstream ring network node adjusts the bandwidth of the best-effort service of the local upper ring according to the calculated fair rate, and sends the calculated fair rate to the upstream ring network node of the upstream ring network node.

Further, the step B32 may include: performing an initial ring network node of the upstream ring network node that receives the fair rate, and performing step B31 and step B32.

The method for adjusting the traffic of the best-effort service of the local upper ring according to the calculated fair rate may be:

Send link layer flow control information to the service source to adjust the transmission traffic of the best-effort service.

The method for adjusting the traffic of the best-effort service of the local upper ring according to the calculated fair rate may also be:

Packets in the local upper ring service that exceed the fair rate portion are discarded.

The link layer flow control information is sent to the service source direction, and the transmission traffic of the best-effort transmission service is adjusted; and the data packet exceeding the fair rate portion of the local uplink service is discarded.

It can be seen from the technical solution provided by the present invention that the present invention can identify the best-effort transmission service according to the information carried by the packet on the node of the MPLS ring network, and then use the fairness algorithm to perform the best-effort transmission. The bandwidth that can be occupied by the service is distributed fairly, so as to ensure that each of the best-effort transmission services transmitted by each network node in the MPLS ring network can occupy the remaining bandwidth resources of the high-priority service fairly and reasonably. The invention effectively The problem that the services of some nodes that may occur in the prior art cannot be sent out at the same time is solved. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of MPLS network service transmission;

2 is a schematic diagram of preempting bandwidth of each service in FIG. 1;

3 is a process flow diagram of the method of the present invention;

Figure 4 shows the format of an MPLS packet. Mode for carrying out the invention

The core idea of the present invention is to identify the best-effort transmission service in the MPLS ring network, and allocate the bandwidth available to the best-effort transmission service for all the best-effort transmission services, so as to ensure that each best-effort transmission service can fairly occupy the remaining high-priority service. Bandwidth resources.

The invention will now be described in detail by way of specific examples.

A specific embodiment of the method for implementing fair delivery of traffic according to the present invention is shown in FIG. 3, and mainly includes the following steps:

Step 31: Determine, on the MPLS ring network node, the best-effort service according to the information carried in the received packet. That is, when the ring network node is congested, the corresponding best-effort service packet is determined from the packet received by the ring network node, so that the best-effort transmission service is processed based on the traffic fair delivery.

In this step, the experimental domain ( EXP ) field reserved in the MPLS packet label Label can be used to identify the best-effort transmission service by carrying the service transmission value in the field. When the best effort transmission service is identified according to the service transmission value of the EXP field, it is necessary to manually configure a threshold in the MPLS ring network node. In addition, when the value of the EXP field in the message label is set for the best effort delivery service, the value is set to be smaller than the above threshold, and the report is set for the non-best effort transmission service. When the value of the EXP field in the text tag is set to a value greater than or equal to the above threshold. Then, when the service transmission value carried by the EXP field in the packet received by the MPLS ring network node is smaller than a preset threshold in the node, the packet is determined to be a packet for best effort transmission. The structure of the MPLS packet label is shown in Figure 4. As can be seen from the figure, the EXP field has 3 bits, and the field can take a value of 0 to 7.

In addition, in this step, a fixed bit in the EXP field may also be utilized, and the fixed bit is set to the best effort service flag for the best effort transmission service in the service transmission process to distinguish it from other services. For example, for the first bit of the EXP field, if the bit is set to 0 if it is a best effort service, then this 0 is the best effort service flag; if it is a non-best effort service, the bit is set to 1. In this way, the MPLS ring network node can judge whether the received service packet is a best-effort service according to the value of the bit.

The service packet discussed in the present invention is a service packet transmitted in the MPLS ring network. Therefore, the MPLS ring network node can also identify the best-effort service packet according to the label value of the LSP. To this end, each node in the MPLS ring network needs to set a dedicated label value of a group of LSPs that transmit the best-effort transmission service, and when transmitting the best-effort transmission service, the best-effort transmission service is transmitted by using the configuration-dedicated LSP, so that The ring network node can determine the best-effort service packet in the received service packet according to the label value.

Of course, in the present invention, whether the service packet received by the ring network node is a best-effort service packet is determined according to the combination of the label value and the EXP field value of the LSP. For example, for a service transmitted by an LSP corresponding to a preset set of LSP label values, a judgment threshold according to whether it is a best-effort transmission service is 5; for an LSP corresponding to another set of LSP label values, The service, based on the judgment of whether it is trying to transmit the service, is based on a judgment threshold of 3.

Step 32: In the MPLS ring network, calculate, according to a fairness algorithm, a bandwidth that the best effort transmission service can occupy, that is, a transmission rate of the allowed best effort transmission service.

In this step, for the inner ring and the outer ring of the MPLS ring, two different loop directions, each ring The calculations are performed independently by using the fairness algorithm. Since the calculation method performed on each ring and the subsequent steps performed are the same, they are not separately described in this embodiment.

The specific fairness algorithm uses the IEEE 802.17 RPR standard algorithm, which includes the following two steps:

(1) First, traffic statistics and supervision (called per-byte);

(2) Then, calculate the corresponding transfer rate based on the traffic counted during the set time. The transmission rate calculated by the above algorithm is the transmission rate of each best effort transmission service allowed, that is, the bandwidth that each best effort transmission service can occupy. Since the algorithm for calculating the rate is basically the same as the existing standard algorithm, it will not be described in detail here.

Step 33: The MPLS ring network node controls the traffic of the local uplink service according to the calculated fair rate, and carries the bandwidth information that can be occupied by the calculated best-effort service in the flow control message to the upstream node in the MPLS ring network. Transfer.

In this step, the traffic control of the local uplink service mainly refers to the processing of the part of the local upper ring service that exceeds the fair bandwidth. The following two different processing methods can be adopted:

(1) transmitting the link layer flow control information in the direction of the service source, and adjusting the transmission traffic of the best-effort transmission service; for example, the method of transmitting the PAUSE frame in the IEEE802.3 protocol may be adopted;

(2) The packet loss mode is to discard the data packet that exceeds the fair bandwidth part of the local uplink service. Specifically, the weighted random early detection (WRED) technology can be used to discard the packet.

The above two methods can be used alone or simultaneously.

In addition, in this step, the bandwidth information that can be occupied by the determined best-effort transmission service is carried in the flow control message and transmitted to the upstream node in the MPLS ring network, so as to adjust the best-effort transmission sent by the upstream node to the failed node. Traffic to the business. Since all neighboring nodes on the MPLS ring network create a bidirectional LSP channel, this step is transmitted in this channel. A flow control packet carrying a calculation result of the fairness algorithm, where the flow control packet may include the following fields:

The fair rate of announcement calculated using the fairness algorithm, that is, the transfer rate calculated in step 32;

The number of hops that were relayed by the message;

The identity of this node;

Of course, other information can be included as needed.

Step 34: After receiving the flow control packet, the upstream node in the MPLS ring network controls the traffic of the best-effort service packet according to the information carried in the packet.

The upstream node that receives the flow control packet in this step can directly control the local ring-ring service according to the fair rate in the packet. The control mode is the same as that of the local ring-ring service in the step 33; The received flow control message is forwarded to the upstream node.

In addition, the upstream node that receives the flow control message in this step may also perform flow control after calculating the fair bandwidth of each best effort transmission service in the node according to the fairness algorithm. The specific control mode is the same as that of the step 33, that is, the flow control of the local uplink service is performed, and the flow control message is sent to the upstream node to control the traffic of the best-effort service sent by the upstream node.

Thereafter, the upstream node that receives the flow control message performs step 34. The specific needs of the physical situation. Therefore, it is to be understood that the specific embodiments of the present invention are intended to be illustrative only and not to limit the scope of the invention.

Claims

Claim

A multi-protocol label switching method for implementing fair delivery of traffic in an MPLS ring network, characterized in that the method comprises:

B. Determine a fair bandwidth that the packet of the best-effort service can occupy, and transmit the packet of the best-effort service based on the fair bandwidth in the MPLS ring network.

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 1, wherein the information carried in the MPLS packet is: a service transmission value set in an EXP field of an experimental domain in an MPLS packet. ;

Then step A is:

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 1, wherein the information carried in the MPLS packet is: a best effort service flag set in a best effort service packet;

Then step A is:

When the received message carries the best-effort service flag, it is determined that the message is a message that tries to transmit the service.

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 3, wherein the best effort transmission service flag is set in a fixed bit of a message EXP field.

The method for implementing the fair delivery of the traffic in the MPLS ring network according to claim 1, wherein the information carried in the MPLS packet is: label switching path LSP label value;

Then the step A is: When the label exchange path LSP label value of the received packet is a pre-configured dedicated label value of the LSP transmitting the best effort transmission service, it is determined that the message is a best effort transmission service message.

The method for implementing the fair delivery of the traffic in the MPLS ring network according to claim 1, wherein the information carried in the MPLS packet is: an LSP label value and a service transmission set in an EXP field of the packet. Value

Then step A is:

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 1, wherein the step B includes:

The method for implementing the fair delivery of the traffic in the MPLS ring network according to claim 7, wherein the step B2 further includes:

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 7 or 8, wherein the information sent to the upstream ring network node is carried by a flow control message.

10. The party for realizing fair delivery of traffic in the MPLS ring network according to claim 7 or 8. Method, wherein the information sent to the upstream ring network node is transmitted through the control information

LSP channel transmission.

The method for implementing fair delivery of traffic in an MPLS ring network according to claim 7, wherein in the step B3, the upstream ring network node that knows the fair rate adjusts the corresponding best effort based on the fair rate. The bandwidth for transmitting service packets includes:

The method according to claim 11, wherein the step B32 further comprises: the upstream ring network node of the upstream ring network node receiving the fair rate performing step B31 and step B32.

The method for realizing fair delivery of traffic in an MPLS ring network according to claim 7 or 11, wherein the method for adjusting the traffic of the best-effort service of the local upper ring according to the calculated fair rate is:

Discard the local ring service

The method for realizing fair delivery of traffic in an MPLS ring network according to claim 7 or 11, wherein the method for adjusting the traffic of the best-effort service of the local upper ring according to the calculated fair rate is: The link layer flow control information is sent to the service source direction, and the sending traffic of the best-effort transmission service is adjusted; and the data packet exceeding the fair rate portion of the local uplink service is discarded.