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An efficient dynamic multicast agent approach for mobile IPv6 multicast. <draft-zhang-mipshop-multicast-dma-01.txt>. Enhui Liu Spencer Dawkins Huawei Technologies Co., Ltd. Hongke Zhang Bo Shen Bingyi Zhang Beijing Jiaotong University. Challenges to Mobile IPv6 Multicast.
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An efficient dynamic multicast agent approach for mobile IPv6 multicast <draft-zhang-mipshop-multicast-dma-01.txt> Enhui Liu Spencer Dawkins Huawei Technologies Co., Ltd. Hongke Zhang Bo Shen Bingyi Zhang Beijing Jiaotong University
Challenges to Mobile IPv6 Multicast • Mobile nodes are different from fixed terminals for their roaming features. What address is used for MNs to join the multicast group membership? Home-Address or Care-of-Address? • One basic method is MIP-BT. Mobile nodes join the multicast group with their Home-Address and receive the multicast data from their home agent via Bidirectional Tunnels. [Disadvantages: triangle routing, long tunnels, large number of tunnels, tunnel congregating, packet latency… ] • Another basic method is MIP-RS. Mobile nodes join the multicast group with their Care-of-Address and receive the multicast data from their foreign agent via Remote Subscription. [Disadvantages: frequent rejoin/leave the multicast group due to CoA changes, the resulting frequent multicast tree restructuring, handover latency, packet loss… ]
Mobile IPv6 Multicast with DMA Concepts: • MSA -- Multicast Subnet Agent, which is the access router running multicast protocols in a subnet and forwarding the subscribed multicast data to the MN that visits the subnet. • DMA -- Dynamic Multicast Agent, which is the current MSA or one of the previous MSAs of the MN acting as the leaf router in a multicast delivery tree the MN subscribed and forwarding the subscribed multicast data to the MN through its current MSA.
Mobile IPv6 Multicast with DMA Multicast Source Internet DMA2 (MSA3) DMA1 (MSA1) MSA2 MN_A MN MN MN_A MN_A MN MN moves from DMA1 to MSA2, (Supposing MN within roaming distance)MN moves from MSA2 to DMA2, (Supposing MN beyond roaming distance)
Mobile IPv6 Multicast with DMA Main Idea: • The MN joins the multicast group membership with its care of address. • When a MN first subscribes a multicast group G, its current MSA becomes its initial DMA. • Within an acceptable roaming distance, the DMA of a MN will not change although its visited MSA changes if its visited MSA doesn't yet have the group G membership in the subnet. • Beyond this acceptable roaming distance, the MN's DMA will be switched to the new MSA that the MN currently is visiting. • When the MN's current MSA is different from its DMA, its current MSA receives the group G multicast data from its DMA via a short tunnel, and then forwards the multicast data to the MN.
Mobile IPv6 Multicast with DMA When the MN's current MSA is different from its DMA,…… Source Multicast Traffic • Multicast Routing Protocol • MLD Report • Multicast Traffic HA PIM Join Msg DMA MSA MN
DMA switch decision-making algorithm Main Principle: • There shouldn’t be any DMA switch for an MN within an acceptable roaming distance if the MN’s visited MSA doesn’t yet have the group G membership in the subnet. Decision-making Algorithm in DMA: • Algorithm is base on movement and distance. It could be simple or precise. • DMA maintains a table to record the MN’s recent attachment history, which is used for decision making. • In the document we just provide a simple algorithm via checking the path increment of the recently joined MSA. It’s distance-based.
Conclusion • The MN joins the multicast group membership with its care of address. • One purpose is to avoid the disadvantage of MIP-BT method: such as triangle routing, long tunnels, large number of tunnels, tunnel congregating, packet latency… • The other purpose is to avoid the disadvantage of MIP-RS method: such as frequent rejoin/leave the multicast group due to CoA changes, the resulting frequent multicast tree restructuring, handover latency, packet loss…
Questions about the draft in the mail list (1) What the difference is between your draft with other similar drafts? There are three main different points: (a) There is a algorithm in our draft. The dynamic and flexible DMA can be selected through this algorithm. (b) They are different in how to switch multicast agent. One method is to select some multicast agent before MN moving. Our method is to select some MSA before MN moving. However the MSA not always become a multicast agent. (c) In our draft, MN do not attend the selection of multicast agent.
The computation of the threshold can be simple or precise. In the version 00, the threshold is computed based on the distance of MN movement. (2) In your draft, how do you compute the threshold?
Thanks for your attention and Suggestion! <draft-zhang-mipshop-multicast-dma-01.txt> Contact info: Spencer Dawkins <sdawkins@futurewei.com> Hong-Ke Zhang <hkzhang@center.njtu.edu.cn>