CN1558636B - Synchronous switching method of source and sink in service flow rerouting - Google Patents

Abstract

The invention relates to a synchronization switching method for source end and host end in business flow route, wherein an expanse field domain MRI is defined in the present existing general purpose framing procedure (GFP). The invention also provides a method for realizing client service route hardware synchronization switching to frames composed thereby by utilizing the said expense, wherein the related instruction / network administration can be cooperated to guarantee the smooth transmission of business flow in the route procedure.

Description

Synchronous switching method of source and sink in service flow rerouting

technical field

The invention belongs to the category of network technology, is a method for ensuring smooth rerouting of service flows in a transmission network, and is a technology applied to a new generation of transmission network that can dynamically provide adjustable bandwidth to customer services, ensuring customer service rerouting In the process, it is a method to achieve lossless transmission when the transmission channel mapping relationship is switched.

Background technique

Due to the suddenness, randomness, and unpredictability of traffic in today's widely used IP services, it is required that the transport network has the function of dynamically providing adjustable bandwidth to customer services. This requires the transport network to have the ability to reroute customer service flows (establish a new transport channel). The traditional implementation method is: after the network management unit or the control plane completes the application for bandwidth resources, notify the source and sink network elements The control/management module is used to configure related software and hardware to realize the switching of business flows between different transmission channels. In this method, the configuration process of the source end and the sink end cannot be synchronized by hardware, so packet loss will occur during the process of switching the transmission path of the data stream. In order to solve this problem, relevant organizations and research and development institutions are conducting relevant research.

Contents of the invention

The present invention adopts a new method to solve the problem of packet loss caused by rerouting in the transport network; this method includes two levels: on the control level, the rerouting-related control level signaling or management level configuration is responsible for the new Select the path and establish a transmission channel connection for it, but the difference from the traditional implementation method is that in the signaling/configuration process, only the source end is switched and configured for the mapping relationship in the electrical layer processing module of the sink end; At the level of data framing, the general framing procedure (GFP) for encapsulation framing and adaptation is extended and supplemented, and the Spare field that has not been defined in ITU-T G.7041 is used to redefine it as MRI (Mapping Realtion Indication) field, as the overhead byte of the GFP client data frame, this field transmits the mapping relationship indication information required for rerouting, and provides a hardware synchronization mechanism between the source end and the sink end of the adaptation—that is, through the GFP frame The overhead byte implements the configuration operation of switching the mapping relationship of the electrical layer processing module at the sink end, thereby ensuring the smooth transmission of the service flow during the rerouting process.

The specific rerouting steps are:

1) Extend and supplement the ITU-T G.7041 GFP standard, use the Spare field that has not been used in the GFP linear extension header, and define it as a mapping relationship indication field, that is, Mapping Realtion Indication (MRI), which is applicable to The configuration source end transmits the mapping relationship indication to the sink end, which provides a means for synchronizing the mapping relationship between the adaptation source end and the sink end, so as to realize smooth rerouting of traffic.

The mapping relationship indicator field, that is, MRI, contains 8 bits and is located in the original Spare field of the GFP linear extension header. Its content is the mapping relationship indicator, which is an overhead byte written by the GFP adaptation source and sent to the GFP receiver. By transmitting the MRI, the source end can send the configuration information of the mapping relationship change to the sink end. This information is sent together with the GFP client data frame as the frame header overhead byte, and when the receiving end unframes the GFP, it will first check this overhead byte, and immediately change the mapping relationship when the local end unframes , and then perform the operation of extracting the GFP client data frame payload and sending it to the client receiving end. This hardware synchronization mechanism makes the change of the mapping relationship between the GFP adaptation source end and the sink end synchronous, so the client data flow carried by it is smooth during the rerouting process.

2) In order to realize the smooth transmission of business flows during the rerouting process, a slight change is made to the traditional control signaling/network management configuration in the rerouting process: for service flow rerouting requests, the network control plane/management unit completes the application for bandwidth resources After that, notify the control/management module in the network element of the source end and the sink end, which will realize the configuration of the relevant software, and only the control/management module of the source end will configure the relevant hardware, that is, apply for rerouting in the hardware Change/switching of the mapping relationship in the service flow to the transmission channel;

3) When the GFP framing, adaptation, and transmission are performed on any channel of customer service flow to the transmission channel, the MRI overhead is provided in the GFP, that is to say, the overhead is transmitted together with the customer data. When the sink end deframes the GFP frame, it will determine the mapping relationship from the transmission channel to the client receiving end according to the MRI domain provided by the current frame, so as to perform deframing. In this way, the adaptation relationship between the client data flow and the transmission channel will be updated in real time along with the client data frame, thus ensuring the hardware synchronization of the adaptation relationship between the source end and the sink end, and effectively avoiding switching transmission paths Packet loss occurs during the process.

As mentioned above, the present invention newly defines an overhead field by extending and supplementing ITU-T G.7041_GFP, and proposes a method for using this overhead to realize hardware synchronous switching when rerouting its framed client services, Cooperating with relevant signaling/network management to ensure smooth transmission of service flows during rerouting, the invention can be applied to a new generation of transport networks that dynamically provide adjustable bandwidth to customer services using traffic-driven or UNI methods. This method has the characteristics of easy implementation, strong flexibility and full utilization of network resources.

Description of drawings

Figure 1 is a schematic diagram of the original GFP linear expansion head and the expanded GFP linear expansion head

Figure 2 is a schematic diagram of the network environment for the application of customer service flow rerouting technology

Figure 3 is a schematic diagram of the rerouting operation using control plane signaling in the transport network

Figure 4 is a schematic diagram of the service transmission situation after the end of operation 2) in step 1 of the customer service flow rerouting technology

Figure 5 is a schematic diagram of the business transmission situation after the operation of 2) in step 2 of the customer service flow rerouting technology

Figure 6 is a schematic diagram of the service transmission situation after the operation of step 3 of the customer service flow rerouting technology

Detailed ways

The rerouting is mainly for the customer service flow carried in the transport network. For the currently widely used IP service, the data traffic from the customer network is sudden, random and unpredictable. Therefore, the transport network should It has the ability to adjust the corresponding bandwidth and even reroute it (establish a new transmission channel for it) according to the change of the service flow from the customer network, so as to realize the efficient utilization of bandwidth resources in the transmission network and provide services that meet customer requirements . Here, the edge node traffic monitoring module of the transport network is responsible for monitoring the service traffic from the customer network, and makes a request for rerouting to the transport network control plane according to the usage status of the path bandwidth resources that have been applied for; or based on UNI signaling , the UNI-C initiates a bandwidth adjustment request as a trigger condition for bandwidth adjustment or rerouting in the transport network; or makes a rerouting request in other possible ways. Once a rerouting request is made, the relevant signaling of the control plane or the network management configuration message will realize the rerouting of the service according to the remaining resources of the network, and configure the nodes, source nodes, and sink nodes that the new channel passes through ; The relevant hardware specifically completes the operation of switching the service flow from mapping to the original transmission channel to mapping to the newly established channel, thereby realizing the whole process of rerouting.

With the widespread application of the general framing technology GFP in the network, a new method of using some overhead bytes of GFP to solve the above problems is proposed.

A specific example of the network environment where this method is applied will be described below with reference to the accompanying drawings.

The general framing procedure is used to transmit the services from the customer data network on the transport network basically in the manner shown in Fig. ) is multiplexed (to achieve traffic aggregation) and framed by the general framing procedure, and then transmitted in the channel (such as WDM channel, etc.) provided by the transport network, and the GFP frame is deframed and demultiplexed at the sink end node. And then sent to the destination customer network. The customer link in the figure takes GbEthernet as an example. The Data/GFP/Transport node includes n-channel customer link GbEthernet line cards. The framing module and the mapping function of m transmission channels. The m transmission channels are dynamically provided by the transmission network, that is, the transmission network can dynamically provide adjustable bandwidth to customer services. In Figure 2, the current transport network only provides one transport channel for services from Data/GFP/Transport node 1 to Data/GFP/Transport node 2, that is, path 1; from router 1, router 2...router n The business flow is multiplexed into frames at Data/GFP/Transport node 1, transmitted in path 1, deframed and demultiplexed at Data/GFP/Transport node 2, and sent to router 1', router 2'... ...router n'.

As the traffic from Router 1 increases, when the sum of the service traffic of n paths is greater than the bandwidth of Path 1, Data/GFP/Transport node 1 will propose to the network control plane to adjust the bandwidth or reroute the traffic from Router 1 ask. If the bandwidth resource of Path 1 is not enough to meet the bandwidth adjustment requirements after analysis, the control plane reroutes the service flow from Router 1 according to the existing resources in the network. The rerouting process is as follows:

Step 1: Control/management plane operations during service traffic rerouting

The control/management plane operation process during service traffic rerouting is as follows:

1) Initiate a rerouting request for a service flow.

Available methods are:

●Based on the intelligent bandwidth monitoring of the edge nodes of the transport network, the bandwidth monitoring program of the edge nodes of the transport network (that is, the source node) proposes a request for service flow rerouting to the control/management plane of the transport network

●Based on UNI signaling, that is, UNI-C sends a bandwidth adjustment request to UNI-N, and UNI-N makes a service flow rerouting request to the transport network control/management plane

●Use other possible methods

2) The control/management plane of the transport network performs a rerouting operation for the request

That is, a new transmission channel is established by means of signaling control or network management configuration, and the client signal that needs to be rerouted is mapped to the newly established transmission channel and the bandwidth occupied by the original transmission channel is released. It should be noted that for the operation of mapping the client signal that needs to be rerouted to the newly established transmission channel and releasing the bandwidth occupied in the original transmission channel, the control and configuration here are only responsible for the relevant software part, not for the relevant hardware. To control and configure, that is to say, only in the software part of each network element, the client signal that needs to be rerouted is mapped to the newly established transmission channel and the bandwidth occupied in the original transmission channel is released, but it is not actually executed on the hardware.

Available methods are:

●Centralized network management is adopted, and the configuration is performed by the network management

Figure 3 shows a schematic diagram of the rerouting operation using control plane signaling in the transport network when the intelligent bandwidth monitoring program of the edge node of the transport network proposes a rerouting request.

After the operation 2) in the above step 1 is completed, the service transmission situation changes as shown in FIG. 4 . Although path 2 has been established in the transmission network, in the hardware of Data/GFP/Transport node 1 and Data/GFP/Transport node 2, the mapping of the client signal that needs to be rerouted to the newly established transmission channel and The operation of releasing the bandwidth occupied in the original transmission channel, so the mapping relationship between GbE and the transmission channel has not changed, and the customer service flow D1 applying for rerouting is still mapped to path 1 for transmission at this time.

Step 2: Configure the relevant hardware at the source end, and use the newly defined GFP overhead to transmit mapping relationship information

1) Configure the relevant hardware at the source end, that is, map a certain route or some service flows applying for rerouting to the newly established transmission channel in the hardware and release the bandwidth occupied in the original transmission channel; Do not configure.

2) When GFP adaptation is performed on any customer service flow to the transmission channel, the Mapping RelationIndication transmission mapping relationship indication field is provided in GFP.

After the operation 2) in the above step 2 is completed, the service transmission situation changes as shown in FIG. 5 . The mapping relationship between GbE and transmission channel in Data/GFP/Transport node 1 has changed, but the mapping relationship between GbE and transmission channel in Data/GFP/Transport node 2 has not changed. On hardware, this When the data/GFP/Transport node 1 at the source end has already mapped the client signal that needs to be rerouted to the newly established transmission channel and released the bandwidth occupied by the original transmission channel, the customer service flow D1 that applied for rerouting is mapped at this time Transfer to the newly established path 2. When the service flow has not yet reached the Data/GFP/Transport node 2 at the sink end, the mapping relationship between the GbE and the transmission channel at the sink end has not changed.

Step 3: As the GFP frame encapsulating the customer service flow and carrying the mapping relationship indication overhead arrives at the sink end, configure the relevant hardware at the sink end to complete the whole process of rerouting. When the GFP frame encapsulating the customer service flow applying for rerouting and carrying the mapping relationship indication overhead arrives at the sink end, the sink end extracts the mapping relationship indication contained in it when deframing the GFP frame, and accordingly converts the current GFP frame The client service payload is sent to the corresponding terminal.

After the above step 3 is completed, the service transmission situation changes as shown in FIG. 6 . Among them, the mapping relationship between GbE and the transmission channel in Data/GFP/Transport node 2 has been changed. On the hardware, the client signal that needs to be rerouted is received from the newly established transmission channel and released on the original transmission channel. The bandwidth occupied by the operation. So far, the whole process of rerouting is completed.

Claims (4)

1. A method for synchronous handover of source and sink in service flow rerouting, characterized in that: the method comprises two levels: on the control level, rerouting-related control level signaling or management level configuration is responsible for the new In the signaling/configuration process, only the source end and not the mapping relationship in the electrical layer processing module of the sink end are switched and configured; at the data framing level, encapsulation will be realized The general framing procedure for framing and adaptation is extended and supplemented, and the remaining field that has not been defined in ITU-T G.7041 is used to redefine it as a mapping relationship indication field, which is used as the overhead byte of the client data frame of the general framing procedure , this field transmits the mapping relationship indication information required for rerouting, and provides a hardware synchronization mechanism between the adapted source end and the sink end, that is, realizes the electrical layer processing of the sink end through the frame overhead byte of the general framing procedure The module performs the configuration operation of switching the mapping relationship, thereby ensuring the smooth transmission of the service flow in the process of rerouting; the steps of rerouting are as follows: 1) Control/management plane operations during service traffic rerouting a) Initiate a rerouting request for a service flow; b) The control/management plane of the transmission network performs rerouting operation for the request, that is, establishes a new transmission channel by means of signaling control or network management configuration, and maps the client signal that needs to be rerouted to the newly established transmission channel and releases the request. The bandwidth occupied in the original transmission channel; but the above operations are only at the control/management level, not the data transmission level, that is, only the software part of each network element maps the client signal that needs to be rerouted to the newly established transmission channel and Release the bandwidth occupied in the original transmission channel without actually executing it on the hardware; 2) Configure the relevant hardware at the source end, and use the newly defined general framing procedure overhead to transmit the mapping relationship information a) Configure the relevant hardware at the source end, that is, map a certain route or some service flows that apply for rerouting to the newly established transmission channel in the hardware and release the bandwidth occupied in the original transmission channel; for the relevant hardware at the sink end Do not configure; b) Provide and transmit the mapping relationship indication field in the general framing procedure when any channel of customer service flows to the transmission channel for general framing procedure adaptation; 3) When the general framing procedure frame encapsulating the customer service flow and carrying the mapping relationship indication overhead arrives at the sink end, the sink end extracts the mapping relationship indication contained in it when deframing the general framing procedure frame, and related to the sink end The hardware is configured to complete the whole process of rerouting. 2. The method for synchronous handover of source and sink in service flow rerouting according to claim 1, characterized in that: said mapping relationship indication field includes 8 bits, which is located in the original remaining field position in the general framing procedure linear extension header , its content is the mapping relationship indication, which is the overhead byte written by the adaptation source end of the general framing procedure and sent to the receiver end of the general framing procedure. The data frame is sent together. 3. The method for synchronous handover of source and sink in service flow rerouting according to claim 1, characterized in that: when encapsulating the customer service flow applying for rerouting and the general framing procedure frame with mapping relationship indicating overhead arrives The sink end, when the sink end deframes the general framing procedure frame, extracts the mapping relationship indication contained in it, and then when the receiving end deframes the general framing procedure frame, it will first check the overhead bytes and change them immediately The mapping relationship when the local end unframes, and then extracts the general framing procedure client data frame payload and sends it to the client receiving end. 4. According to the method for synchronous handover of source and sink in service flow rerouting according to claim 3, the general framing procedure is used for framing, adaptation and transmission in the transmission channel of any customer service flow in the general framing procedure The mapping relationship indicator field overhead is provided in the Frame, that is to say, the overhead is transmitted along with the client data. When the sink deframes the frame of the general framing procedure, it will determine the secondary transmission channel according to the mapping relationship indicator field provided by the current frame. The mapping relationship between client data stream and transmission channel will be updated in real time along with the client data frame.

Images