System and method of delivering multicast service system on mobile host computers

Abstract

The invention relates to a system and a method for a mobile host to carry out multicast services. In the present invention, each mobile host corresponds to a dynamic multicast agent, and the dynamic multicast agent needs to realize dynamic switching according to the path passed by the mobile host in the moving process, if the dynamic multicast agent of the mobile host is switched to the current subnet MSA, then the MSA directly joins the multicast group at this time, which optimizes the multicast transmission path. Therefore, the present invention can not only reduce the frequent reconstruction of the multicast tree caused by the movement of the host, but also effectively avoid the formation of an overly long tunnel between the dynamic multicast agent DMA and the MSA of the foreign subnet, and optimize the transmission path of the multicast group. In addition, the present invention can make full use of network resources, prevent the multicast agent from becoming the bottleneck of network communication, and at the same time avoid the occurrence of tunnel aggregation problems.

Description

technical field [0001] The invention relates to the technical field of network communication, in particular to a system and a method for a mobile host to carry out multicast services. Background technique [0002] Multicast technology is a routing technology that optimizes the use of network bandwidth. Multicast technology allows IP data streams to be sent from one source or multiple sources to multiple destinations. The use of multicast technology is beneficial to reduce backbone network traffic, so IP multicast has always been a hot issue in the field of Internet research. At present, in the mobile environment, it is urgent to combine IP multicast and mobile IP technology to provide multicast services for mobile nodes (ie, mobile hosts), that is, to realize mobile IP multicast technology. [0003] For mobile IP multicast, the multicast protocol not only needs to manage the multicast group members, establish and maintain the multicast forwarding tree, but also solve the d...

AI Technical Summary

Problems solved by technology

[0008] 1. Because the triangular route is used, it is not the optimal route, so there must be a disadvantage of large link overhead

Especially when the mobile node is far away from the home network and joins the local multicast group of the foreign link, the additional overhead introduced by this scheme will be very significant

[0009] 2. Since the home agent forwards multicast packets for each mobile node through the tunnel, it is done in the form of unicast, so when the home agent has multiple corresponding mobile nodes on the same foreign link, each A mobile node will establish a tunnel to this home agent, and each mobile node receives multiple duplicate multicast packets through different tunnels, which will cause "tunnel aggregation problem"

[0010] 3. Home Agents Become "Points of Failure"

[0013] 1. When the mobile node is a multicast receiver and handover occurs, due to the rejoining of the multicast group and the update of the multicast forwarding tree, the handover delay is relatively large, which will cause more multicast packet loss and affect the group broadcast application reliability

[0014] 2. When the mobile node is used as a multicast source, it can only be applied to the shared tree

So it will introduce a lot of protocol overhead

[0015] 3. Due to the different delays of receiving multicast packets in each subnet, the unique "synchronization loss" problem in the mobile environment occurs

This will inevitably add new overhead

[0020] 3. Multicast packet loss caused by DMSP reselection

[0023] 1. The multicast agent is close to the interface of the multicast backbone network. If it fails, the affected area is relatively large

[0024] 2. When the multicast tree is reconstructed, the multicast service is interrupted for a long time

[0025] To sum up, in mobile multicast, every time a node switches between subnets due to movement, it will rejoin the multicast tree as a new member, which will lead to frequent updates and replays of the multicast tree. This structure brings too much overhead to the management of multicast groups and the maintenance of multicast distribution trees, which increases the burden on the network, and also makes the communication recovery time of mobile nodes longer, which seriously affects the communication quality.

Although many schemes have been proposed, these schemes generally have many defects including triangular routing, tunnel aggregation, long switching delay, excessive packet loss, etc.

Images