WO2009111990A1

WO2009111990A1 - Multicast controlling method, device and system

Info

Publication number: WO2009111990A1
Application number: PCT/CN2009/070776
Authority: WO
Inventors: 黄勇; 查敏
Original assignee: 华为技术有限公司
Priority date: 2008-03-13
Filing date: 2009-03-13
Publication date: 2009-09-17
Also published as: CN101534203B; CN101534203A

Abstract

A multicast controlling method, device and system, the method including steps: receiving an joining request of the first edge node to a multicasting group, or a leaving request of the first edge node to a multicasting group; when receiving the joining request, searching a latest joining copy node corresponding to the first edge node; when receiving the leaving request, searching a latest leaving copy node corresponding to the first edge node; allocating bandwidth resource between the found latest joining copy node and the first edge node, or releasing bandwidth resource between the found latest joining copy node and the first edge node.

Description

Method, device and system for multicast control

This application claims priority to Chinese Patent Application No. 200810026778.4, entitled "Method, Apparatus and System for Multicast Control", filed on March 13, 2008, the entire disclosure of which is incorporated by reference. In this application. The present invention relates to the field of communications technologies, and in particular, to a method, device, and system for multicast control. Background technique

At present, the TV-type service provided on the Internet is called IPTV. The IPTV service basically has two forms of video on demand (VoD, Video on Demand) and broadcast television (BTV, Broadcast TV), in which VoD transmits television programs through unicast. The BTV service specifically refers to a television program transmitted by broadcasting or multicast on an IP network. The video service occupies a lot of network bandwidth resources. When a large number of video programs are flooded on the network, it will randomly compete for the limited bandwidth of the network. To ensure the quality of services, the network needs to manage the resources occupied by the network. According to the idle status of the bandwidth resources, whether to allow a certain service to occupy network bandwidth or release network bandwidth is called resource admission and release control. The existing technology implements the resource admission and release control of the multicast service in the core network. The existing multicast protocol technology is to establish a multicast tree for the media stream corresponding to each multicast group. In the core network domain, when there is a huge amount of media streams, the multicast routers that perform multicast routing management will consume processing resources by a large number of multicast routing protocol packets, and the storage space will be occupied by a large number of multicast state records. Network capacity is difficult to expand due to these limitations. This problem is called scalability. In addition, in the prior art solution, the process of multicast transmission does not have a bandwidth guarantee mechanism. For an egress node that newly joins the multicast group, it is easy to wait for the bandwidth resource to be allocated for a long time, the media stream cannot be smoothly transmitted, or one is to leave. The egress node of a multicast group cannot release bandwidth resources in time, which may cause network congestion. SUMMARY OF THE INVENTION Based on the above deficiencies of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a multicast control method, device, and system, which implements unified management of multicast bandwidth resources, and responds to an edge node requesting to join or leave in time. A request from a multicast group dynamically allocates bandwidth resources.

An embodiment of the present invention provides a method for multicast control, including the following steps: receiving a request for joining a multicast group by a first edge node, or a request for leaving a multicast group by a first edge node; when receiving a join request Using the unicast route to send a lookup packet to the downstream node to find the nearest join copy point corresponding to the first edge node; or when receiving the leave request, use the unicast route to find the nearest leave copy point corresponding to the first edge node The search packet carries the label identifier of the first edge node, the multicast label of the multicast group, and the label identifier of the egress node of the multicast group; when the recently added copy point is found, Requesting to reserve bandwidth resources for the recently added replication point to the first edge node, and after receiving the resource acknowledgement response signal, modifying the multicast label of the multicast group to join the first edge node to the multicast Group; or when the recently left copy point is found, the request releases the bandwidth resource between the recently left copy point and the first edge node, and is in the connection After receiving the resource confirmation response signal, the multicast label of the multicast group is modified to delete the first edge node from the multicast group.

Correspondingly, an embodiment of the present invention further provides a network node, including:

a receiving unit, configured to receive a join request of the first edge node to the multicast group, or a leave request of the first edge node to the multicast group; and receive a resource reservation acknowledgement response or a resource release acknowledgement response;

a searching unit, configured to: according to the received join request to the multicast group, find the nearest join point of the first edge node on the forwarding link of the media stream of the multicast group; or according to the received pair of multicast groups The leaving request, on the forwarding link of the media stream of the multicast group, find the nearest leaving copy point of the first edge node;

a sending unit, configured to send a bandwidth resource reservation request between the found nearest joining copy point to the first edge node, or send a bandwidth resource release request between the found nearest leaving copy point to the first edge node;

a processing unit, configured to: after receiving the resource reservation confirmation response, modify the multicast label of the multicast group to join the first edge node to the multicast group; or after receiving the resource release confirmation response, modify the A multicast label of a multicast group to delete the first edge node from the multicast group.

a receiving unit, configured to receive a recent join of the first edge node that finds the request to join the multicast group The lookup message of the point, or the lookup message of the nearest leaving copy point of the first edge node that requests to leave the multicast group, the lookup message includes the label identifier of the first edge node and the current receiving multicast group. a label identifier of a network edge node of the media stream, and a multicast label of the multicast group;

a determining unit, configured to calculate, according to the received search message, a current multicast label by using a unicast route, and determine whether it is a recently added copy point or a recently left copy point;

The sending unit is configured to: when the judgment result is yes, send the node identifier of the node to the ingress node of the multicast group; when the judgment result is no, the device forwards the search packet to the downstream node according to the unicast route, and the search packet is searched. The multicast label in the modification is changed to the current multicast label.

Certainly, the embodiment of the present invention further provides a system for multicast control, including:

a first edge node, a second edge node, an intermediate node, and a network resource management node;

The first edge node is configured to send a join request to the multicast group, or send a leave request to the multicast group;

The second edge node is configured to receive a join request of the first edge node to the multicast group, or receive a leave request of the first edge node to the multicast group, according to the received first edge node joining the multicast group And sending, on the forwarding link of the media stream of the multicast group, a lookup packet for finding a recently added copy point; or, according to the received first edge node leaving the multicast group, the media stream in the multicast group On the forwarding link, the device searches for a lookup packet that has recently left the replication point; the lookup packet carries the label identifier of the first edge node, the multicast label of the multicast group, and all the exit nodes of the multicast group. a label identifier; after finding the nearest join copy point, requesting the network resource management node to reserve a bandwidth resource between the recently added replication point and the first edge node, and receiving the resource confirmation response sent by the network resource management node After the signal is modified, the multicast label of the multicast group is modified to join the first edge node to the multicast group; or when the nearest copy point is found, The network resource management node requests to release the bandwidth resource between the recently left replication point and the first edge node; and after receiving the network resource management node resource sending the acknowledgement response signal, modify the multicast label of the multicast group to The first edge node is deleted from the multicast group;

The intermediate node is configured to receive a lookup packet sent by the second edge node, calculate a current multicast label by using a unicast route according to the lookup packet, and determine whether the intermediate node itself is recently added to the replication point or recently left. Copying the point; if yes, reporting to the second edge node; if otherwise forwarding the lookup packet to the downstream node on the forwarding link of the media stream of the multicast group, changing the multicast label in the lookup message to the Current multicast label; The network resource management node is configured to perform bandwidth resource reservation after receiving a request for reserving bandwidth resources between the recently added replication point and the first edge node sent by the second edge node, and when the reservation is successful Transmitting a resource acknowledgment response to the second edge node; or receiving a request for releasing the bandwidth resource between the recently leaving the replication point and the first edge node sent by the second edge node, releasing the bandwidth resource, and releasing the resource after the resource is released The edge node sends a resource acknowledgment response.

Embodiments of the present invention have the following beneficial effects:

The process of uniformly managing multicast transmission can be implemented, especially when an egress node newly joins or quits a multicast group, and the nearest join copy point is reserved in time by searching for the nearest join copy point corresponding to the egress node or leaving the copy point recently. The bandwidth between the egress nodes, or the bandwidth that has recently left the replication point to the egress node, enables efficient and reasonable allocation of bandwidth resources. Increased network bandwidth utilization. DRAWINGS

1 is a schematic diagram of a method for implementing multicast admission control according to an embodiment of the present invention;

2 is a schematic diagram of a method for implementing multicast release control according to an embodiment of the present invention;

3 is a network diagram of a method for implementing multicast admission control according to an embodiment of the present invention; FIG. 4 is a flowchart of a method for implementing multicast admission control according to an embodiment of the present invention;

5 is a network diagram of a method for implementing multicast release control according to an embodiment of the present invention; FIG. 6 is a flowchart of a method for implementing multicast release control according to an embodiment of the present invention;

7 is a system block diagram of a multicast control according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of an entry node according to an embodiment of the present invention; FIG.

9 is a schematic structural diagram of an intermediate node according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a network resource management node according to an embodiment of the present invention. The embodiments of the present invention provide a method for implementing multicast resource admission and release control, which uses a Multi-Protocol Label Switching (MPLS) label to identify a multicast packet to be reached. All network egresses, a packet with an MPLS multicast label can identify the egress that the packet is currently pointing to at any node in the network. The multicast label changes with the process of forwarding, when an interface from a node Packet group sent by other interfaces of this node when sent to a specific exit The broadcast tag no longer contains the identity of the particular exit, thus automatically avoiding forwarding loops.

First, the method for implementing multicast admission control in the embodiment of the present invention is described in the principle. Referring to FIG. 1, in a network domain composed of nodes (1) to (11), a media stream having a multicast group <g, S> is transmitted according to a forwarding path of a current arrow connection, where the multicast group < 8 The entry node of > is the node

(1), the egress node is the nodes (8) and (11). When a new egress node (7) needs to join the multicast group, it must find the node with the shortest path on the existing media stream forwarding link. Thereby establishing a new multicast forwarding path.

In Figure 1, among all the nodes that have received the media stream, only the node (4) and the new egress node (7) have the shortest unicast forwarding path, so that the node (4) is the closest join point.

The recently added replication point is a node in the network domain and meets the following three conditions: a) The node has received the media stream of the multicast group when a new egress node requests to join the multicast group; b) the node is located on the current unicast forwarding path from the network ingress node corresponding to the multicast group to the new egress node joining the multicast group;

c) The unicast forwarding path of the node to the new egress node is the shortest.

The method for implementing multicast release control in the embodiment of the present invention is described in the principle. Referring to FIG. 2, in a network domain composed of nodes (1) to (11), a media stream having a multicast group <g, s> is transmitted according to a forwarding path of a current arrow connection, where the multicast group < 8 The entry node of > is node (1), and the egress node is node (7), (8), (9), (11). When an egress node (8) needs to leave the multicast group, it must find and existing On the media stream forwarding link, the shortest multicast forwarding branch node releases the bandwidth resource between the multicast forwarding branch node and the egress node (8).

In Figure 2, among all the multicast forwarding branch nodes that have received the media stream, only the unicast forwarding path from the node (4) to the egress node (8) is the shortest, so that the multicast forwarding node (4) is recently left. Copy the point. Although there is a node (5) between the node (4) and the egress node (8), the node (5) is not a multicast forwarding branch node that has received the media stream currently, that is, a hub node that forwards the media stream (in a group) The broadcast group forwards the media stream to the node on more than one downstream node), so the node (5) is not the closest to the replication point.

The recently left replication point is a multicast forwarding branch node in the network domain and meets the following three conditions:

a) the node has received the media stream of the multicast group when the egress node requests to leave the multicast group; b) the node is located from the network ingress node corresponding to the multicast group to the egress node of the leaving multicast group On the current unicast forwarding path;

C) There is no other multicast forwarding branch node on the multicast forwarding path of the node to the egress node leaving the multicast group.

As shown in FIG. 3, it is a schematic diagram of a network for implementing a multicast resource admission control method according to an embodiment of the present invention.

In the orthogonal label-based network domain, in order to identify each edge node and map the identifier to the label, a label identifier needs to be defined for each edge node, for example, defining labels for edge nodes eight, B, C, and D. The identifiers are 0x00001, 0x00002, 0x00004, 0x00008, and the label identifiers of all edge nodes are orthogonal, that is, the result of any two label identifiers is 0. The media stream of a multicast group <g, s> is sequentially transmitted from the path of the node B, Y, Z, D, wherein the ingress node of the multicast group <g, s> is the node B, and the egress node is the node D; The multicast label is the label of each egress node of the multicast group. That is, the multicast label of the multicast group <g, s> is the label ID 0x00008 of the egress node D.

As shown in Figure 4, when a new egress node A needs to join the multicast group, the method for implementing multicast admission control is as follows:

101. The request to join the multicast group <8> arrives at the exit node A.

102. The egress node A sends a request for joining the multicast group with the own tag identifier to the network resource manager RM, and the RM centrally stores all the ingress node information corresponding to the multicast group <8>.

103. After the network resource manager finds the ingress node B corresponding to the multicast group <g, s>, the RM forwards the request of the egress node A to the multicast group to the ingress node B.

The request of the egress node A to join the multicast group <g, s> is forwarded to the ingress node B through the network resource manager RM, which is formally a stream represented by a quintuple whose destination address is a multicast address. Of course, the request to join the multicast group may also be received by the RM from the other RM through the inter-domain interface, and then forwarded to the ingress node B; or sent directly by the node A to the ingress node B through unicast.

After receiving the request to join the multicast group <g, s>, the ingress node B sends a unicast route to send a packet to the nearest join point, where the lookup packet carries the egress node requesting to join the multicast group. The tag identifier of A is 0x00001 and the tag identifier of the egress node that has received the multicast group <8> media stream, that is, the tag identifier 0x00008 of the current egress node D, and the multicast tag 0x00008 of the multicast group <8>.

The ingress node B sends a lookup message for finding the most recently added copy point, and sends it to the downstream node to let all the nodes that have received the media stream perceive the processing. Therefore, the information carried in the search packet is also multicast. The tag of the ingress node B of <g,s> is 0x00002.

105. The downstream intermediate node Y receives the lookup packet, and determines whether it is the closest join copy point to the exit node A. Specifically, the intermediate node Y calculates the reachability of all the egress nodes by using the unicast route on each of the egress interfaces, and calculates the label of each egress interface label. The sum of all egress node label identifiers that are reachable on the outbound interface, and the label mask of the outbound interface. Since the lookup packet carries a multicast label, the intermediate node Y can know that the egress node A passes through the intermediate node Z according to the current unicast route. The intermediate node Y associates the label mask 0x00009 with the multicast label 0x00008 in the lookup 4, and obtains the exit label of the intermediate node Y to the egress node A as 0x00008, and the egress label is obtained after exchanging labels through the intermediate node Y. Current multicast label. Because the intermediate node Z is forwarding the media stream to the egress node D on the unicast forwarding path of the egress node A, the calculated current multicast label in the direction of the egress node A is not zero, indicating that the intermediate node Y to the egress node The unicast forwarding path of A is not the shortest. This can be judged that the intermediate node Y is not recently added to the copy point. The intermediate node Y then forwards the lookup packet to the downstream intermediate node Z. The multicast label in the lookup packet is the current multicast label 0x00008. The intermediate node Y determines the direction of the egress node as the node D according to the multicast label in the lookup packet, and calculates the label mask of the outbound interface in the direction of the node D. The egress interface label is the egress node (whether or not the egress node The sum of the tag identifiers in the multicast group, that is, the sum of the tag identifiers of the egress nodes A and D 0x00009.

106. After receiving the lookup message, the intermediate node Z also determines whether it is the closest join point to the exit node A. Specifically, the intermediate node Z calculates the label mask of the egress interface of the egress node A by using a unicast route to be 0x00001, and the label mask 0x00001 is matched with the received current multicast label 0x00008 to obtain the intermediate node Z to the egress. The egress label of node A is zero. The egress label is the current multicast label obtained after the intermediate node Z exchanges labels. The current multicast label to the egress node A is zero, which indicates that the intermediate node Z to the egress node A No media stream is forwarded on the unicast forwarding path, thereby determining that the intermediate node Z is the closest join copy point. The intermediate node Z sends a unicast response signal to the ingress node B according to the label identifier of the ingress node B, or other identifiers, and reports that it is the most recently added copy point of the current search.

107. After receiving the unicast response signal, the ingress node B sends a resource admission request to the network resource manager RM, requesting to reserve the multicast bandwidth resource from the intermediate node Z to the egress node A.

The intermediate node Z can also directly report to the network resource manager RM that it is the most recently added replication point of the current lookup, and sends a resource admission request, requesting the RM reservation from the intermediate node Z to the exit node A. Multicast bandwidth resources.

108. Network Resource Manager The RM completes resource reservation and gives a resource confirmation response signal.

109. After receiving the resource confirmation response signal, the ingress node B changes the multicast label corresponding to the multicast group <&8>, and also uses the newly added egress node A as an egress node of the multicast group <8> media stream. Thus, the multicast group media stream is forwarded from the intermediate node Z to the egress node A.

Correspondingly, as shown in FIG. 5, it is a schematic diagram of a network for implementing a multicast resource release control method according to an embodiment of the present invention.

In the orthogonal label-based core network, in order to identify each edge node and map the identifier to the label, an identifier needs to be defined for each edge node, for example, a label is defined for the edge nodes A, B, C, and D in advance. The identifiers are 0x00001, 0x00002, 0x00004, 0x00008, and the label identifiers of different edge nodes are orthogonal, that is, the result of any two label identifiers is 0. The media stream with a multicast group <g, s> is sequentially transmitted from the path of the node B, Y, Z, D and the path from the node: 8, Υ, Ζ, Α, where the entry of the multicast group <8> The node is the node B, and the egress node is the node D and the A. The multicast label of the multicast group is the sum of the identifiers of the egress node A and the D tag, that is, the multicast tag of the multicast group <8> is 0x00009.

Referring to FIG. 6, when an egress node A needs to leave the multicast group, the method for implementing multicast release control is as follows:

201. The request to leave the multicast group <g, s> reaches the exit node A.

202. The egress node A sends a request to leave the multicast group with the own tag identifier to the network resource manager RM, where the RM stores all the ingress node information corresponding to the multicast group.

203. The network resource manager, after finding the ingress node B corresponding to the multicast group <g, s>, sends the request of the egress node A to leave the multicast group to the ingress node B.

The request of the egress node A to leave the multicast group <g, s> is forwarded to the ingress node B through the network resource manager RM, which may be a stream represented by a quintuple whose destination address is a multicast address. Of course, the leaving multicast request may also be received by the RM from the other RM through the inter-domain interface, and then forwarded to the ingress node B; or sent by the egress node A to the ingress node B by unicast.

After receiving the request to leave the multicast group <g, s>, the ingress node B sends a packet to the nearest leaving replication point by using the unicast route, where the lookup packet carries the label identifier of the egress node A. 0x00001 and the label ID 0x00008 of the egress node D that has received the multicast group <g, s> media stream, and the multicast label 0x00009 of the multicast group <g, s>. The ingress node B sends a lookup message for the nearest leaving of the replication point, and sends it to the downstream node, so that all the nodes that have received the media stream are aware of the processing, so the information carried in the search packet also corresponds to the multicast group < 8 > The tag identifier of the ingress node B.

205. The downstream intermediate node Y receives the lookup packet, and determines whether it is the nearest leaving replication point to the egress node A. Specifically, the lookup packet carries the multicast label, and the intermediate node Y learns that the egress node A passes through the intermediate node Z according to the current unicast route, and the label mask of the outbound interface in the Z direction of the intermediate node is 0x00009. The label mask is the sum of the IDs of the egress node A and the D tag. The intermediate node Y calculates the reachability of all egress nodes through unicast routes on each outbound interface, and calculates the label mask of each egress interface. The sum of the label IDs of all egress nodes that are reachable on the outbound interface, and the label mask of the egress interface. The intermediate node Y determines the direction of the egress node as the node D according to the multicast label, and calculates the label mask of the outbound interface in the direction of the node D. The outbound interface label is the egress node (whether the egress node is in the multicast group or not) Irrelevant) The sum of the tag identifiers, that is, the sum of the tag identifiers of the exit nodes A and D 0x00009.

Then, the label mask 0x00009 is matched with the multicast label 0x00009 carried in the search text, and the exit label of the intermediate node Y to the exit node A is 0x00009. The egress label is the current multicast label obtained after the label is exchanged by the intermediate node Y. Because the path to the egress node A also has the multicast forwarding branch node Z forwarding the media stream to the egress node D, the current group is calculated. The broadcast tag is the sum of the two exit node A and D tag identifiers, which can determine that the intermediate node Y is not the closest to the copy point. The intermediate node Y forwards the lookup packet to the downstream intermediate node Z. The multicast label carried in the lookup packet is the current multicast label 0x00009.

206. The intermediate node Z is a multicast forwarding branch node. After receiving the lookup packet, it determines whether it is the closest leaving replication point to the egress node A. Specifically, the intermediate node Z calculates a label mask of the outbound interface to the exit node A by using a unicast route to be 0x00001, and the label mask is matched with the received current multicast label 0x00009, and the obtained exit label is 0x00001, the egress label 0x00001 is the current multicast label obtained after the intermediate node Z exchanges labels, because the value of the current multicast label in the direction from the intermediate node Z to the egress node A is equal to the label identification value of the egress node A. This means that no other multicast forwarding branch nodes are forwarding the media stream between the intermediate node Z and the egress node A, thereby determining that the intermediate node Z is the closest leaving the replication point. The intermediate node Z sends a unicast response signal to the ingress node B according to the label identifier of the ingress node B, and reports that it is the nearest leaving copy point of the current lookup.

207. After receiving the unicast response signal, the ingress node B sends the resource to the network resource manager RM. The release request requests to release the multicast bandwidth resource from the intermediate node to the egress node.

The intermediate node Z can also directly report to the network resource manager RM that it is the nearest leaving replication point of the current lookup, and send a resource admission request, requesting the RM to release the multicast bandwidth resource from the intermediate node Z to the egress node A.

208. The network resource manager sends a resource confirmation response signal after the RM completes the resource release.

209. After receiving the resource confirmation response signal, the ingress node B changes the multicast sending label of the corresponding multicast group <&8>, and deletes the egress node A from the multicast group <^8>. Thus, the intermediate node Z no longer forwards the media stream of the multicast group <g, s> to the egress node A.

A method for implementing multicast resource admission control or a method for implementing multicast resource release control provided by the embodiment of the present invention. The network resource management node can be used to uniformly manage the multicast transmission process, especially when an egress node newly joins or exits the multicast group, and finds the nearest join copy point corresponding to the egress node or recently leaves the replication point, and reserves in time. The bandwidth of the replication point to the egress node is recently added, or the bandwidth between the egress node and the egress node is released in time to realize dynamic and reasonable allocation of bandwidth resources. Increased network bandwidth utilization.

In addition, in this embodiment, the multicast forwarding process of each node does not depend on the multicast routing protocol, but identifies a network domain edge node, and uses the forwarding tree for a multicast group in the topology of the network domain from the portal. The forwarding topology of the node to the egress node is described. In this way, all multicast groups with the same forwarding topology in the network domain perform no separate multicast transmission in the network domain, thereby realizing multicast convergence. The identifier of the network edge node to be reached is uniformly placed in a multicast label and carried by the multicast packet traversing the network domain. The node can implement multicast forwarding by using the multicast label information. Based on this technology, the intermediate nodes do not need to maintain the forwarding state of each multicast group, which reduces the number of management packets.

To implement the above multicast control method, as shown in FIG. 7, the embodiment of the present invention further provides a multicast control system, where the network domain includes: a network resource management node, an ingress node, an intermediate node, and an egress node. The ingress node, the intermediate node, and the egress node may all be routers in hardware, but the functions implemented are different.

The egress node is configured to send a request to join the multicast group or leave the multicast group. Specifically, the egress node analyzes the requirement of the media stream that the user receives the multicast group, and sends a join request to the multicast group by using the sending unit. , or a request to leave a multicast group;

The ingress node is configured to send a lookup packet to the downstream node of the multicast group according to the received request that the egress node joins the multicast group, and find the latest join with the shortest forwarding path between the egress node. Copying a point; or sending a lookup packet to a downstream node of the multicast group according to the received request that the egress node leaves the multicast group, and searching for the closest leaving copy point with the shortest forwarding path between the egress node; The packet carries the multicast label of the multicast group and all the egress node label identifiers of the multicast group, and the label identifier of the egress node that requests to join or leave; after finding the nearest join point, the request is for the egress node to Reserving resources between recently joined replication points, or requesting to release resources between the egress node and the nearest leaving replication point after finding the nearest leaving replication point; and tampering with the group after receiving the resource reservation confirmation response The multicast label of the multicast group is added to the egress group of the multicast group to join the multicast group; or after receiving the resource release confirmation response, modify the multicast label of the multicast group to leave the request The egress node of the multicast group is deleted from the multicast group.

Specifically, the ingress node includes:

a receiving unit, configured to receive a request for joining the multicast group by the egress node, or a request for leaving the multicast group by the egress node;

a searching unit, configured to: according to the received join request of the egress node to the multicast group, search for the shortest recent join replication with the egress node on the forwarding link of the media stream of the multicast group Or: according to the received leaving request of the egress group to the multicast group, on the forwarding link of the media stream of the multicast group, searching for the closest leaving copy point with the shortest forwarding path between the egress node;

a sending unit, configured to send the discovered bandwidth resource reservation request between the recently added replication point to the egress node, or send the discovered bandwidth resource release request between the recently left replication point to the egress node To the network resource management node;

The processing unit is further configured to: after receiving the resource reservation confirmation response, modify the multicast label of the multicast group to join the egress group of the request to the multicast group to join the multicast group; or receive the resource After the acknowledgment response is released, the multicast label of the multicast group is modified, and the egress node that leaves the multicast group is deleted from the multicast group.

The search unit described above includes:

a packet generating unit, configured to generate a lookup packet, where the lookup packet includes a label identifier of the egress node, a label identifier of all network edge nodes that currently receive the media stream of the multicast group, and a group of the multicast group Broadcast label; may also include the label identifier of the entry node itself;

a message sending unit, configured to send the lookup message to a node on the multicast group media stream forwarding link; The response receiving unit is configured to receive the node identifier of the most recently joined replication point, or the node identifier of the most recently left replication point.

The intermediate node in the system is configured to calculate a current multicast label by using a unicast route according to the received search packet, and determine whether the intermediate node itself joins the recently copied point or recently leaves the copy point; if yes, the The ingress node of the multicast group reports that if the downstream node on the media stream forwarding link of the multicast group forwards the lookup packet, the multicast label in the lookup packet is modified to the current multicast label.

The intermediate node includes:

a receiving unit, configured to receive a lookup message for finding a recently added copy point or a recently left copy point, where the lookup message includes a label identifier of an egress node that requests to join the multicast group and a network that currently receives the multicast group media stream a label identifier of the edge node, or a label identifier of the egress node requesting to leave the multicast group and a label identifier of the network edge node currently receiving the multicast group media stream;

a determining unit, configured to calculate, according to the received lookup message, a current multicast label by using a unicast route, and determine whether it is the recently added copy point or the recently left copy point;

a sending unit, configured to: when the judgment result is yes, send the node identifier of the node to the ingress node of the multicast group; if the judgment result is no, the received search packet is forwarded according to the unicast route to the The media stream of the multicast group forwards the downstream node on the link.

The determining unit described above includes:

a multicast label switching unit, configured to: associate a label mask of an outgoing interface of the egress node with the multicast label of the multicast group, and obtain an exchanged multicast label; And calculating, according to the label identifier of the network edge node of the media stream that is currently receiving the multicast group in the packet, using the unicast route, calculating a label mask of the outbound interface on the forwarding path of the egress node, and the specific calculation method See method embodiment.

a comparison processing unit, configured to determine whether the current multicast label is zero, if yes, determine that it is the closest join point; or determine whether the current multicast label is equal to the label identifier of the egress node requesting to leave the multicast group, and if yes It is determined that it is the most recent departure point.

The network resource management node RM includes:

a receiving unit, configured to receive a bandwidth resource reservation request sent by the ingress node to the egress node, or receive a bandwidth resource release request between the egress node and the egress node sent by the ingress node; Receiving, by the egress node, a request for joining a multicast group, or a request for leaving the multicast group by the egress node; a processing unit, configured to reserve, according to the received bandwidth resource reservation request, a bandwidth resource that is recently added to a replication point to the egress node; or release the latest according to the received bandwidth resource release request Leaving the copy point to the bandwidth resource between the egress nodes.

The network resource management node further includes:

a forwarding unit, configured to search for an ingress node corresponding to the multicast group according to the received join request or leave request, and send the received join request of the egress node to the multicast group or the egress node to the multicast group Leaving the request, forwarding to the ingress node;

a bandwidth allocation confirmation unit, configured to send a resource reservation confirmation response to the ingress node after the processing unit reserves the bandwidth resource between the most recently added replication point and the egress node; or in the processing unit After releasing the bandwidth resource that has recently left the replication point to the egress node, a resource release confirmation response is sent to the ingress node. In a multicast control system, the network resource management node, the ingress node, the intermediate node, and the egress node are all connected by a link or connected by a wireless network, and the network resource management node may be a gateway. , or the interconnected border point gateway, or server, centrally stores information about all ingress nodes corresponding to the multicast group <g, S, such as the ingress node identifier.

The system has a simple structure. The multicast forwarding process of each node does not depend on the multicast routing protocol. That is, the intermediate node does not need to maintain the state of each group. This reduces the number of management packets and prevents network congestion. The system manages the multicast transmission process through the network resource management node. In particular, when an egress node joins or quits a multicast group, the multicast label is modified in time to dynamically allocate bandwidth resources.

To further illustrate a multicast control system of an embodiment, as shown in FIG. 8, an embodiment of the present invention further provides an ingress node 80, including:

The receiving unit 801 is configured to receive a request for joining the multicast group by the egress node, or a request for leaving the multicast group by the egress node, and is also used for receiving a resource reservation confirmation response or a resource release confirmation response sent by the network resource management node.

The searching unit 802 is configured to: according to the received join request of the egress group to the multicast group, search for a shortest nearest join copy point with the egress node on the forwarding link of the corresponding multicast group media stream; or And according to the received leaving request of the egress group to the multicast group, searching for the nearest leaving copy point with the shortest forwarding path between the egress node and the forwarding link of the corresponding multicast group media stream;

The sending unit 803 is configured to send the discovered bandwidth resource reservation request between the recently added replication point to the egress node, or send the discovered bandwidth resource between the recently left replication point and the egress node. Release a request to the network resource management node;

The processing unit 804 is configured to modify the multicast label of the multicast group according to the received resource reservation confirmation response, to join the egress node to the multicast group, or release an acknowledgment response according to the received resource Modifying the multicast label of the multicast group to remove the egress node from the multicast group.

The search unit 802 described above includes:

The message generating unit 8021 is configured to generate a lookup message, where the lookup message includes a label identifier of the egress node, a label identifier of a network edge node that currently receives the multicast group media stream, and a multicast group multicast group. The tag; may also include the tag identifier of the ingress node 80 itself.

a message sending unit 8022, configured to send the lookup message to a downstream node of a media stream forwarding link of the multicast group;

The response receiving unit 8023 is configured to receive the node identifier of the most recently joined copy point, or the node identifier of the closest leaving the copy point.

As shown in FIG. 9, the embodiment of the present invention further provides an intermediate node 90, including: a receiving unit 901, configured to receive a lookup packet for finding a recently added copy point or a recently left copy point, where the lookup message includes a request. The label of the egress node that joins and leaves the multicast group, the label of the network edge node that receives the media stream of the multicast group, and the multicast label of the multicast group. The search packet may also include the multicast group. The tag identifier of the ingress node 80.

The determining unit 902 is configured to calculate, according to the received search message, a current multicast label by using a unicast route, and determine whether it is the recently added copy point or the recently left copy point; the sending unit 903 When the judgment result is yes, the node identifier of the multicast group is sent to the ingress node of the multicast group; when the judgment result is no, the downstream node on the link is forwarded to the media stream of the multicast group according to the unicast route. Forward the search packet and change the multicast label in the lookup packet to the current multicast label.

The determining unit 902 includes:

The multicast label switching unit 9021 is configured to calculate, according to the label identifier of the network edge node of the media stream that currently receives the multicast group in the packet, use the unicast route to calculate the forwarding path to the egress node. The label mask of the interface is matched with the multicast label of the multicast group to obtain an exchanged multicast label, that is, the current multicast label. For the specific calculation process, refer to the method embodiment.

The comparison processing unit 9022 is configured to determine whether the exchanged multicast label value (current multicast label) is zero, and if it is zero, determine that it is the latest join copy point; or determine the exchange Whether the multicast tag value is equal to the tag identifier value of the egress node, and if equal, it is determined that it is the most recently left copy point.

The network nodes shown in Figures 8 and 9 can be the same type of network device, such as a router, so the network device can have the functions of an ingress node, an egress node, and an intermediate node at the same time, and can be set to be functionally selectable, so that the operator can For its own needs, there is no same device in the network, such as a router, which is set as an edge node or an intermediate node according to the location of the device.

As shown in FIG. 10, the embodiment of the present invention further provides a network resource management node 100, including:

The receiving unit 101 is configured to receive the join request of the egress node to the multicast group, or the egress request of the egress node to the multicast group; of course, the receiving unit is further configured to receive the latest join copy point sent by the ingress node to a bandwidth resource reservation request between the egress nodes, or a bandwidth resource release request between the egress node and the egress node;

The forwarding unit 102 is configured to forward the received join request of the egress node to the multicast group or the exit request of the egress node to the multicast group to the ingress node;

The processing unit 103 is configured to reserve, according to the received bandwidth resource reservation request, a bandwidth resource that is recently added to the replication point to the egress node, or release the content according to the received bandwidth resource release request. Recently leaving the replication point to the bandwidth resource between the egress nodes;

The bandwidth allocation confirmation unit 104 is configured to reserve, according to the processing unit, the bandwidth resource between the recently added replication point and the egress node, and send a resource reservation confirmation response to the ingress node; or according to the processing unit Release the bandwidth resource between the nearest leaving replication point to the egress node, and send a resource release confirmation response to the ingress node.

A system and a network node device for implementing multicast resource admission control or release control provided by the embodiments of the present invention can use the network resource management node to uniformly manage the multicast transmission process, especially when an egress node newly joins or exits. In the case of a multicast group, the bandwidth of the most recently added copy point to the egress node is reserved in time by searching for the nearest join copy point corresponding to the egress node or the nearest leave copy point, or releasing the recently left copy point to the The bandwidth between the egress nodes enables dynamic and reasonable allocation of bandwidth resources. Increased network bandwidth utilization.

The above is a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto. It should be noted that those skilled in the art can also omit the principles of the present invention without departing from the scope of the present invention. A number of improvements are made which are also considered to be within the scope of the invention.

Claims

Rights request

A method for multicast control, comprising the steps of:

Receiving a request for joining the multicast group by the first edge node, or a request for leaving the multicast group by the first edge node;

When receiving the join request, sending a lookup message to the downstream node by using a unicast route to find a nearest join copy point corresponding to the first edge node, or using the unicast when receiving the leave request The route sends a lookup packet to the downstream node to find the nearest leave replication point corresponding to the first edge node, where the search packet carries the label identifier of the first edge node, where the multicast group a multicast label and a label identifier of an egress node of the multicast group;

After finding the recently joined replication point, requesting to reserve bandwidth resources between the recently added replication point and the first edge node, and modifying the group of the multicast group after receiving the resource confirmation response signal Broadcasting a label to join the first edge node to the multicast group; or, after finding the most recently left copy point, requesting to release bandwidth resources between the recently left copy point and the first edge node; After receiving the resource confirmation response signal, modifying the multicast label of the multicast group to delete the first edge node from the multicast group.

2. A method of multicast control according to claim 1, wherein:

When the request for the join is received, the unicast route is used to send a lookup packet to the downstream node, and the latest join copy point corresponding to the first edge node is searched, which specifically includes:

When receiving the join request, the unicast route is used to send a lookup packet to the node on the media stream forwarding link of the multicast group, and determine whether the node on the multicast group media stream forwarding link is Adding a copy point recently;

When the detachment request is received, the unicast route is used to send a lookup packet to the downstream node to find the nearest leaving replication point corresponding to the first edge node, which specifically includes:

When the leaving request is received, the unicast route is used to send a lookup packet to the node on the multicast group media stream forwarding link, and it is determined whether the node on the multicast group media stream forwarding link is the Recently left the copy point.

3. A method of multicast control according to claim 2, wherein Determining whether the node on the forwarding group of the multicast group media stream is the closest join copy point, specifically:

Determining whether the multicast group media stream is forwarded on the shortest forwarding path of the node on the multicast group media stream forwarding link to the first edge node, and if not, determining the multicast group media. The node on the flow forwarding link is the recently added copy point;

Determining whether the node on the forwarding group of the multicast group media stream is the closest leaving replication point, specifically:

Determining whether there is another multicast forwarding branch node on the forwarding path of the node on the multicast group media stream forwarding link to the first edge node, and if not, determining that the multicast group media stream is forwarded on the link The node is the most recently left copy point.

The method of multicast control according to claim 2 or 3, wherein the determining whether the node on the forwarding link of the multicast group media stream is the most recently added copy point includes :

The node on the multicast group media stream forwarding link calculates the label mask of the outbound interface on the forwarding path of the first edge node according to the unicast route and the multicast label in the received lookup packet, and The label mask is matched with the multicast label of the multicast group carried in the search packet, and the exchanged multicast label is obtained. If the exchanged multicast label is zero, the multicast group medium is determined. The node on the stream forwarding link is the most recently added copy point;

The node on the multicast group media stream forwarding link calculates the label mask of the outbound interface on the forwarding path of the first edge node according to the unicast route and the multicast label in the received lookup packet, and The label mask is matched with the multicast label of the multicast group carried in the search packet, and the exchanged multicast label is obtained, if the exchanged multicast label value and the label of the first edge node are If the identifier values are equal, it is determined that the node on the multicast group media stream forwarding link is the most recently left replication point.

The method for multicast control according to claim 1 or 2, wherein before the request reserves bandwidth resources between the recently added copy point and the first edge node, Including, receiving the report sent by the recently added copy point is itself the most recent addition of the current search Information into the copy point;

Or before the request releases the bandwidth resource between the recently left replication point and the first edge node, the method further includes: receiving the report sent by the nearest leaving replication point, which is the nearest leaving replication point of the current search. information.

The multicast control method according to claim 5, wherein the recent join replication point satisfies the following condition: when the first edge node requests to join the multicast group, the latest Receiving the replication point has received the multicast group media stream; the recent join replication point is located on a current unicast forwarding path from the multicast group ingress node to the first edge node; The unicast forwarding path to the first edge node is the shortest;

The recent leaving replication point satisfies the following condition: when the first edge node requests to leave the multicast group, the most recent leaving replication point has received the multicast group media stream; From the multicast group ingress node to the current unicast forwarding path of the first edge node; there is no other multicast forwarding branch node on the multicast forwarding path of the nearest leaving replication point to the first edge node.

7. A network node, comprising:

a locating unit, configured to find, according to the received join request for the multicast group, the latest join replication with the shortest forwarding path between the first edge nodes on the forwarding link of the media stream of the multicast group Pointing; or, according to the received leaving request for the multicast group, finding the closest leaving copy point with the shortest forwarding path between the first edge nodes on the forwarding link of the media stream of the multicast group; a sending unit, configured to send a found bandwidth resource reservation request between the recently added replication point to the first edge node, or send the discovered bandwidth resource between the recently left replication point and the first edge node Release request

a processing unit, configured to: after receiving the resource reservation confirmation response, modify the multicast label of the multicast group to join the first edge node to the multicast group; or after receiving the resource release confirmation response, modify A multicast label of the multicast group to remove the first edge node from the multicast group. 8. A network node according to claim 7, wherein:

The searching unit includes:

a message generating unit, configured to generate a lookup message, where the lookup message includes a label identifier of the first edge node, and a label identifier of a network edge node that currently receives the multicast group media stream, and the multicast Group multicast label;

a message sending unit, configured to send the lookup message to a downstream node on a media stream forwarding link of the multicast group;

The response receiving unit is configured to receive the node identifier of the most recently joined replication point, or the node identifier of the most recently separated replication point.

9. A network node according to claim 7 or 8, characterized in that

The recent join replication point satisfies the following condition: when the first edge node requests to join the multicast group, the latest join replication point has received the multicast group media stream; From the multicast group ingress node to the current unicast forwarding path of the first edge node; the unicast forwarding path of the most recently added replication point to the first edge node is the shortest;

10. A network node, comprising:

a receiving unit, configured to receive a lookup message of a recently added copy point of the first edge node that requests to join the multicast group, or receive a lookup report of the nearest leaving copy point of the first edge node that requests to leave the multicast group The search packet includes a label identifier of the first edge node and a label identifier of a network edge node that currently receives the multicast group media stream, and a multicast label of the multicast group; Calculating the current multicast label by using the unicast route according to the received search packet, and determining whether it is the recently added copy point or the recently left copy point;

a sending unit, configured to send a node identifier of the node to the ingress node of the multicast group when the judgment result is yes; and when the judgment result is no, forward the link to the media stream of the multicast group according to the unicast route The upstream node forwards the lookup packet and modifies the multicast label in the lookup packet to the current multicast label.

11. A network node according to claim 10, characterized in that

The determining unit includes:

a multicast label switching unit, configured to calculate a forwarding path of the first edge node by using a unicast route according to a label identifier of a network edge node that currently receives the media stream of the multicast group in the search packet Label the label of the outgoing interface, and the label mask is matched with the multicast label of the multicast group to obtain the current multicast label.

a comparison processing unit, configured to determine whether the current multicast label is zero, and if yes, determine that the current multicast label is the closest join copy point; or determine whether the current multicast label is equal to the label identifier of the first edge node, If so, it is determined that it is the most recent leaving copy point.

A network node according to claim 10 or 11, characterized in that

The recent joining of the replication point satisfies the following condition: when the first edge node requests to join the multicast group, the recently joined replication point has received the media stream of the multicast group; Located on the current unicast forwarding path from the multicast group ingress node to the first edge node; the unicast forwarding path of the most recently added replication point to the first edge node is the shortest;

The recent leaving replication point satisfies the following condition: when the first edge node requests to leave the multicast group, the most recent leaving replication point has received the media stream of the multicast group; Located on the current unicast forwarding path from the multicast group ingress node to the first edge node; there is no other multicast forwarding branch node on the multicast forwarding path of the nearest leaving replication point to the first edge node .

A multicast control system, comprising: a first edge node, a second edge node, an intermediate node, and a network resource management node;

The second edge node is configured to receive a request for joining the multicast group by the first edge node, or receive a request for leaving the multicast group by the first edge node, according to the received first edge node pair A multicast group join request, on the forwarding link of the media stream of the multicast group, sending a search to join recently And a lookup message of the copy point; or, according to the received leaving request of the first edge node to the multicast group, sending a lookup packet for finding the nearest leaving copy point on the forwarding link of the media stream of the multicast group The search packet carries the label identifier of the first edge node, the multicast label of the multicast group, and the label identifier of all the egress nodes of the multicast group; when the recently added copy is found After the point, requesting, by the network resource management node, to reserve bandwidth resources between the recently added replication point and the first edge node, and after receiving the resource confirmation response signal sent by the network resource management node, modify the a multicast label of the multicast group to join the first edge node to the multicast group; or, after finding the most recently left copy point, requesting the network resource management node to be the closest leaving copy point to the first And releasing the bandwidth resource between the edge nodes; and after receiving the acknowledgement response signal sent by the network resource management node, modifying the multicast label of the multicast group, so as to The first edge node is deleted from the multicast group;

The intermediate node is configured to receive a lookup packet sent by the second edge node, calculate a current multicast label by using a unicast route according to the lookup packet, and determine whether the intermediate node itself is newly added to the replication point or Leaving the replication point recently; if yes, reporting to the second edge node, otherwise forwarding the lookup packet to the downstream node on the forwarding link of the media stream of the multicast group, and searching for the multicast label in the packet Modified to the current multicast label;

And the network resource management node is configured to perform bandwidth resource reservation after receiving the request for the bandwidth resource reserved by the second edge node to send the copy point to the first edge node, and reserve the bandwidth resource Sending a resource acknowledgment response to the second edge node when successful; or receiving a request for releasing the bandwidth resource between the recently left copy point and the first edge node sent by the second edge node, performing bandwidth resource release, and After the resource is released, a resource confirmation response is sent to the second edge node.

14. The system of claim 13 wherein:

The intermediate node specifically includes:

a receiving unit, configured to receive a lookup packet sent by the second edge node, where the lookup packet includes a label identifier of the first edge node and a label identifier of a network edge node that currently receives the multicast group media stream And the multicast label of the multicast group, where the multicast label switching unit is configured to use the unicast route according to the label identifier of the network edge node that currently receives the multicast group media stream in the lookup packet, Calculating a label mask of the outbound interface on the forwarding path of the first edge node, and matching the label mask with the multicast label of the multicast group to obtain a current multicast label; a comparison processing unit, configured to determine whether the current multicast label is zero, if yes, determine that it is the most recently added replication point; or determine whether the current multicast label value is equal to the label of the first edge node The flag, if yes, determines that it is the most recently left copy point.

15. A system according to claim 13 or claim 14 wherein:

The recent join replication point satisfies the following condition: when the first edge node requests to join the multicast group, the latest join replication point has received the multicast group media stream; From the second edge node of the multicast group to the current unicast forwarding path of the first edge node; the unicast forwarding path of the most recently added replication point to the first edge node is the shortest;

The recent leaving replication point satisfies the following condition: when the first edge node requests to leave the multicast group, the most recent leaving replication point has received the multicast group media stream; From the second edge node of the multicast group to the current unicast forwarding path of the first edge node; there is no other multicast forwarding on the multicast forwarding path of the nearest leaving copy point to the first edge node Branch node.