WO2007009335A1

WO2007009335A1 - A method for realizing the multicast service in an automatic switch optical network

Info

Publication number: WO2007009335A1
Application number: PCT/CN2006/001212
Authority: WO
Inventors: Hao Zi
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-06-04
Filing date: 2006-06-05
Publication date: 2007-01-25
Also published as: CN100531117C; CN1874293A

Abstract

A method for realizing the multicast service in an automatic switch optical network, which distributes GroupID for multicast service, comprises: when the node in the ASON establishes the one-way service for multicast service, determines whether the LSP of GroupID of the current multicast included in the identifier information is existed in the node, if it is not, then the node establishes the one-way service according to the normal process, and the LSP identifier information of the established one-way service includes the GroupID of the multicast service, then finish the process; otherwise, the node judges whether the existent LSP is the same to the output link of the one-way service, if it is, after the one-way service establishes the LSP, the source and the target time slots and the interconnect of the existent LSP is used directly; if it is not, after the one-way service establishes the LSP, the source time slot of the existent LSP is used directly and the target time slot is distributed and the interconnect is needed to be established. The present invention realizes the share of the time slot of the multicast service, and improves the resource utilization factor and the operating efficiency of the network.

Description

Method for realizing multicast service in automatic switched optical network

Technical field

The present invention relates to digital information transmission technologies, and in particular, to a method for implementing multicast services in an automatic switched optical network.

Background technique

The services in the Automatically Switched Optical Network (ASON) mainly include one-way point-to-point, two-way point-to-point and one-way point-to-multipoint connection. The optical multicast service is a one-way point-to-multipoint connection, and refers to a set of one-way service connections with the same source end entry and different sink end exits.

The Resource Reservation Protocol (RSVP) includes the RSVP-TE (RSVP-TE, RSVP-Traffic Engineering) signaling protocol. The RSVP-TE signaling protocol is used as the signaling protocol of the ASON control plane, and its role is to establish and maintain services. For example, in ASON, a protocol packet such as RSVP-TE is used to establish a protocol data packet related to the service, and is transmitted to each node in the network through a channel such as an overhead byte of the SDH network in the control plane, and each node is The establishment of the service according to the content of the received protocol data packet, thereby completing the connection establishment of the entire service from the source node to the sink node. The establishment of the service is to establish a label switched path (LSP), and then the data can be transmitted through the established LSP to implement the service.

For the optical multicast service with unidirectional point-to-multipoint connection, the most direct way to implement the optical multicast service is to use the LSP establishment procedure of the RSVP-TE signaling protocol to establish a set of homologous different sinks and time slots. One-way business.

Figure 1 shows an established solution for optical multicast services. As shown in Figure 1, the optical multicast service actually establishes three unidirectional services. The three unidirectional services use different LSP links. The three LSP links are:

LSP1 : A->B->F _;

LSP2: A->B->C->D;

LSP3: A—>B—>C— >G.

As can be seen from the above description, although the RSVP-TE signaling protocol can be used in the ASON network. It is proposed to establish a set of unidirectional services allocated by different sets of different sinks and time slots to implement multicast services, but since each unidirectional service established is independent, the time slots in each link are also allocated, even if LSP1 The path of A->B in LSP2 and LSP3 is the same, and the time slot cannot be shared in the part of the path. Similarly, the path of B->C in LSP2 and LSP3 is the same, but the time slot cannot be shared. . Obviously this causes a waste of time slot resources.

Summary of the invention

In view of the above, the main purpose of the present invention is to provide a method for implementing a multicast service in an ASON, which implements time slot sharing of an optical multicast service and effectively utilizes time slot resources to overcome the waste of time slot resources in the prior art. Defects.

In order to solve the above problems, the present invention provides the following technical solutions:

A method for implementing a multicast service in an automatic switched optical network, the method first assigning a multicast group number (GroupID) to a multicast service, and the method further includes the following steps:

If the node in the ASON is configured to establish a unidirectional service for the multicast service, it is determined whether the LSP of the current multicast service group ID exists in the local device. If not, go to step b. Otherwise, go to step c. ;

The node establishes an LSP for the unidirectional service, allocates a source and a sink slot for the LSP, and establishes a cross-connection, and the identifier information of the established LSP includes the GroupID of the multicast service, and then the processing ends. Process;

The node determines whether the existing LSP is the same as the egress link of the unidirectional service to be established currently. If the LSP is the same, the LSP is directly used after the LSP is established for the unidirectional service. Source and sink timeslots and cross-connections; if different, after establishing an LSP for the unidirectional service, directly use the source time slot of the existing LSP, allocate a sink time slot, and establish a cross-connection.

The group ID assigned to the multicast service is: Assign a unique GroupID to all multicast services in the automatic switched optical network.

The group ID assigned to the multicast service is: assigning a unique GroupID to all multicast services under the same first node;

In step a, before the step c is performed, the node further includes: determining whether the first node of the existing LSP is the same as the first node of the one-way service that is currently to be established, and if yes, Go to step C, otherwise, go to step 13.

In the step a, before the performing step c, the node further comprises: determining whether the ingress link and the source time slot of the existing LSP are the same as the ingress link and the source time slot of the currently established unidirectional service. If they are all the same, step c is performed; if the ingress links are different, and/or the source time slots are different, the processing flow is ended.

In the step a, after determining that the ingress link is different, and/or the source time slot is different, and before ending the processing flow, the node further includes: performing an error reporting process.

The method may further comprise:

When the node in the ASON deletes the unidirectional service of the multicast service, it determines whether the other LSP exists in the local node, and the group ID included in the identifier information of the other LSP and the identifier information of the LSP of the unidirectional service are included. The groupID is the same, if it does not exist, go to step e, otherwise, go to step f;

e. The node directly deletes the LSP of the unidirectional service, deletes the source and sink time slots and the cross connection of the LSP, and ends the processing flow;

f. The node determines whether the unidirectional service has the same egress link as the other LSPs existing on the node, and if yes, deletes only the LSP of the unidirectional service; otherwise, deletes the unidirectional The LSP of the service, and only the slot slots and cross-connections are released.

In step d, before the step f is performed, the node further includes: determining whether the first node of the other LSP existing by the node is the same as the first node of the one-way service, and if yes, performing step f; otherwise , perform step ^

In the step d, before the step f is performed, the node further includes: determining whether the ingress link and the source time slot of other LSPs existing by the node are the same as the ingress link and the source time slot of the unidirectional service If they are all the same, step f is performed; if the ingress links are different, and/or the source time slots are different, the process flow ends.

In the step d, after determining that the ingress link is different, and/or the source time slot is different, and before ending the processing flow, the node further includes: performing an error reporting process.

The GroupID allocated for the multicast service is a non-zero value. The beneficial effects of the present invention are: in the present invention, the GroupID is allocated for the multicast service, and the GroupID of the multicast group is added to the identification information of the LSP, and the same group is determined by the judgment of the GroupID based on the processing of the existing LSP. slots shared between different multicast traffic unidirectional service, i.e., each service node of the link determination is performed, processing in accordance with the multicast service Gr _0U pID different unidirectional traffic, the inlet and outlet links link, etc., in order to achieve The time slot sharing of the multicast service effectively utilizes the time slot resources, which improves the resource utilization and operation efficiency of the network.

DRAWINGS

1 is a schematic diagram of application of the prior art;

2 is a schematic view of the application of the present invention;

3 is a schematic diagram of a process flow for establishing a unidirectional service by a node in the solution of the present invention;

FIG. 4 is a schematic diagram of a process flow of deleting a unidirectional service by a node in the solution of the present invention.

detailed description

Taking the ASON network shown in Figure 2 as an example, it is assumed that a multicast service needs to be established in the network, and the multicast service needs to include four unidirectional services, and the four unidirectional services respectively correspond to four LSPs. The LSP is as follows:

LSP1 : A->B->F

LSP2: A->B->C->G

LSP3: A->B->C->D->H

LSP4: A->B->C->D->E

If the route is to be created, the node sends a message according to the obtained routing information according to the obtained routing information, establishes an LSP, allocates a time slot for the LSP, and establishes a cross-connection of each node. That is, the connection of the source slot to the sink slot of the node is established. For the existing scheme, when allocating time slots and establishing a cross-connection, the A node and the B node in FIG. 2 need to allocate 4 source slots and sink slots, and establish 4 for the source slot and the sink slot. For the secondary cross-connection, the C-node needs to allocate 3 source slots and sink slots, and establish 3 cross-connections for the source slot and the sink slot.

In fact, in any one of the same multicast services, different LSPs of the same multicast service must have the same ingress link and source time slot. Therefore, when establishing each unidirectional service of the same multicast service, If the time slot is allocated for the LSP of the one-way service and the cross-connection is established, it can be confirmed If the LSP belongs to the same multicast service as the previously established LSP, the LSPs established by the node for the same multicast service can share at least the source time slot.

Of course, different LSPs of the same multicast service may have the same egress link at the node, as the A node in FIG. 2 has the same egress link, and the B node in FIG. 2 is between the node and the C node. This link also has the same egress link. Therefore, if the LSP is determined to belong to the same multicast service as the previously established LSP, and the LSP has the same egress link as the previously established LSP, before the LSP is allocated to the LSP and the cross-connection is established, The LSPs established by the node for the same multicast service can directly share the source and sink slots, and since the source and sink slots are all original slots, in this case, no cross-connection is established.

Based on the above analysis, when creating a multicast service, you need to assign a multicast group number (GroupID) to the multicast service. Therefore, when establishing the unidirectional service of the multicast service, in addition to setting the input parameters of the common LSP of the unidirectional service, the group ID of the multicast service to which the LSP belongs is also required to be added, so that each node according to the The GroupID determines whether the node has an LSP that belongs to the same multicast service. The identification information of the LSP, in addition to the original information, should also include a GroupID, where the original information usually includes: an IPv4/IPv6 tunnel end node address, a tunnel ID, an extended tunnel ID, an IPv4/IPv6 tunnel sender address, and The LSP ID, and the IPv4/IPv6 tunnel sender address is the address of the first node of the multicast service.

GroupID can be added to the current Path, Resv, PassErr, and ResvErr message data structures as an object. The group ID should be set. For example, if the group ID is set to 0, the corresponding LSP is not a multicast service. If the group ID is non-zero, the corresponding LSP is a multicast service. Belong to the same multicast service.

After the above group ID is set, each node should perform the processing shown in Figure 3 when establishing a one-way service for the multicast service. The processing corresponds to the following steps:

Steps 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301 301

In this step, the normal service establishment process is: allocate an LSP for the service, allocate a source and sink time slot for the LSP, and establish a cross-connection, and the identifier information of the established LSP should be included. The GroupID of the multicast service.

Steps 303 to 305: determining whether the egress link of the existing LSP is the same as the egress link of the unidirectional service to be established currently. If the LSP is the same, the existing LSP is directly used after the LSP is established for the unidirectional service. Source and sink timeslots and cross-connections of the LSP, that is, the shared source and sink time slots, and the cross-connection is not required to be established; if different, the source of the existing LSP is directly used after the LSP is established for the unidirectional service. Gap, but need to allocate sink slots, and need to establish cross-connections.

Through the above steps, it is possible to establish an LSP while ensuring that different LSPs of the same multicast service can share time slots as much as possible.

The above processing requirement can assign a unique GroupIDo to all multicast services in ASON.

Obviously, if there are many multicast services in the ASON, a GroupID may not be uniquely associated with a multicast service. Therefore, when identifying a multicast service, all multicast services under the same node in the ASON can be assigned uniquely. GroupID, the first node is the source ingress node of the multicast service. Based on the allocation scheme, before the step 303 is performed, the node needs to determine whether the first node of the existing LSP is the same as the first node of the unidirectional service to be established, and may be based on the IPv4/IPv6 in the LSP identification information. The tunnel sender address is judged. If the same, it indicates that the existing LSP belongs to the same multicast service as the current one-way service, so step 303 can be performed; but if the two head nodes are different, the The existing LSP has the same GroupID as the current unidirectional service, but does not belong to the same multicast service. Therefore, step 303 cannot be performed. The unidirectional service should be established according to the normal processing flow.

It can be seen from the above that when the GroupID is the same, the first node is the same, the source time slots are the same, and the ingress link and the egress link are the same, the LSPs of the unidirectional services in the multicast service share the source and sink slots. As shown in Figure 2, among the four businesses:

In Figure 1, where 1 is the A->B link, LSP1, LSP2, LSP3, and LSP4 share the source and sink slots;

In Figure 2, 2, that is, B->C link, LSP2, LSP3, and LSP4 share source and sink slots; in Figure 3, 3, that is, C->D link, LSP3, LSP4 share source and sink slots.

Since there may be some erroneous situations, for example, it is assumed that the node finds that the ingress link and the ingress slot of the unidirectional service to be established currently exist and the ingress link and the ingress slot of the existing LSP exist. In different cases, the difference may be different only for the ingress link, or only the ingress slot is different. Of course, the ingress link and the ingress slot are different, regardless of the unidirectional service to be established and the exit of the existing LSP. If the link is the same, the above situation should not exist under the guarantee of the routing multicast algorithm. Therefore, the node should end the process of establishing the one-way service in this case, and of course, can perform error processing.

After the multicast service is established, the multicast service is usually deleted, and the unidirectional service in the multicast service is deleted.

The LSP of the present invention is based on the LSP sharing time slot of the unidirectional service. Therefore, when the node initiates the deletion of a unidirectional service in the multicast service according to the RSVP protocol, the LSP of the unidirectional service and the local node are required. Whether other LSPs share time slots to determine whether to release the time slot and whether to delete the cross-connection while deleting the LSP of the one-way service.

The deletion will be described in detail below. As shown in FIG. 4, the deletion process corresponds to the following steps:

Steps 401 to 402: When the node needs to delete the unidirectional service of the multicast service, it determines whether there are other LSPs of the GroupID included in the identification information of the LSP including the unidirectional service in the identification information, and if not, directly follow the LSP. If the LSP is deleted, the LSP of the unidirectional service is deleted, the source and sink slots are released, and the cross-connection is deleted. Otherwise, step 403 is performed.

Steps 403 to 405, further determining whether the unidirectional service has the same egress link as the other LSPs existing. If yes, the source and sink slots are not released, and the cross-connection is not deleted, but the one-way service needs to be deleted. LSP; otherwise, only the slot is released, but the source slot is not released, but the corresponding cross-connection needs to be deleted, and the LSP to be deleted is deleted.

The LSP deletion of the multicast service is implemented through the above processing.

As mentioned above, the GroupID may uniquely identify a certain multicast service in the ASON, and may also identify multiple multicast services in the ASON. If it is the former case, the flow shown in Figure 4 can be directly executed. If the latter case is performed, before performing the above step 403, that is, whether to determine whether the same egress link is present, whether the unidirectional service and the other LSPs existing have the same head node, and if so, Then, the determination process of step 403 is performed; otherwise, the deletion is performed according to the normal situation, that is, the LSP of the one-way service is deleted, the source and sink time slots are released, and the cross-connection is deleted. When deleting a multicast service, there may be some erroneous situations. For example, it is assumed that the node finds that the ingress link of the unidirectional service to be deleted is different from the ingress link of other existing LSPs, and/or is to be deleted. The ingress slot of the unidirectional service is different from the ingress link of other existing LSPs. Regardless of whether the egress link is the same, this situation should not exist under the guarantee of the routing multicast algorithm, so the node can end the current Deleting the processing of one-way services, of course, can also perform error handling.

While the invention has been described by the embodiments of the invention in the embodiments of the invention Request to limit.

Claims

Claim

A method for implementing a multicast service in an automatic switched optical network, characterized in that a multicast group number GroupID is allocated for a multicast service, and the method further comprises the following steps:

If the node in the automatic switching optical network ASON establishes a unidirectional service for the multicast service, it determines whether the LSP of the current multicast service group ID exists in the identity information. If not, execute step b. Otherwise, , performing step c;

The node establishes an LSP for the unidirectional service, allocates a source and sink time slot for the LSP, and establishes a cross-connection, and the identifier information of the established LSP includes the GroupID of the multicast service, and then the processing ends. Process;

The node determines whether the existing LSP is the same as the egress link of the unidirectional service to be established currently. If the LSP is the same, the LSP is directly used after the LSP is established for the unidirectional service. Source and sink time slots and cross-connections; if different, after establishing an LSP for the unidirectional service, directly use the source time slot of the existing LSP, allocate a sink time slot, and establish a cross-connection.

The method according to claim 1, wherein the group ID assigned to the multicast service is: assigning a unique GroupE to all multicast services in the automatic switched optical network.

The method according to claim 1, wherein the group ID assigned to the multicast service is: assigning a unique GroupID to all multicast services under the same first node;

In step a, before the step c is performed, the node further includes: determining whether the first node of the existing LSP is the same as the first node of the one-way service that is currently established, and if yes, performing step 0, otherwise, performing step 1?.

The method according to any one of claims 1 to 3, wherein in the step a, the node further comprises: determining the ingress link and source of the existing LSP before performing step c Whether the time slot is the same as the ingress link and the source time slot of the unidirectional service to be established currently, if they are all the same, step c is performed; if the ingress link is different, and/or the source time slot is different, the process is terminated.

The method according to claim 4, wherein in the step a, after determining that the ingress link is different, and/or the source time slot is different, and before ending the processing flow, the node further Including: Perform error handling.

The method according to claim 1, wherein the method further comprises: d. determining, by the node in the ASON, whether the node has other LSPs when deleting the unidirectional service of the multicast service, and the other LSP The group ID included in the identification information is the same as the GroupID included in the identification information of the LSP of the unidirectional service. If not, step e is performed, otherwise, step f is performed;

e. The node directly deletes the LSP of the unidirectional service, deletes the source and sink timeslots and cross-connections of the LSP, and ends the processing flow;

f. The node determines whether the unidirectional service has the same egress link as the other LSPs already existing on the node, and if yes, deletes only the LSP of the unidirectional service; otherwise, deleting the one-way service The LSP of the service, and only the slot slots and cross-connections are released.

The method according to claim 6, wherein the group ID assigned to the multicast service is: assigning a unique GroupID to all multicast services under the same head node;

In step d, the node, before performing the step, further includes: determining whether the first node of the other LSP existing by the node is the same as the first node of the one-way service, and if yes, performing step f; otherwise, Go to step 6.

The method according to claim 6 or 7, wherein in the step d, the node further comprises: determining the ingress link and the source time slot of other LSPs existing by the node before performing the step £ Whether it is the same as the ingress link and the source time slot of the unidirectional service, if they are all the same, step f is performed; if the ingress links are different, and/or the source time slots are different, the process flow ends.

The method according to claim 8, wherein in the step d, after determining that the ingress link is different, and/or the source time slot is different, and before ending the processing flow, the node further includes : Perform error handling.

The method according to claim 1, wherein the GroupID allocated for the multicast service is a non-zero value.