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Mobile IP Multicasting with Host Mobility Locality. Gihwan Cho ghcho@cs.chonbuk.ac.kr Chonbuk University. Outline. Internet host mobility support Multicasting Problems identified Existing works Host movement locality approach. Reference
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Mobile IP Multicasting with Host Mobility Locality Gihwan Cho ghcho@cs.chonbuk.ac.kr Chonbuk University APCC : Wireless Internet Nov. 2, 2000
Outline • Internet host mobility support • Multicasting • Problems identified • Existing works • Host movement locality approach Reference 1. A. Acharya, A. Bakre and B. R. Badrinath, “IP Multicast Extensions for Mobile Internetworking,” IEEE INFOCOM’96, 1996, pp.67-75 2. V. Chikarmane et al. “Multicast Support for Mobile Hosts Using Mobile IP: Design Issues and Proposed Architecture,” ACM/Baltzer Mobile Networking and Applications, 3(4), pp.365-379, Jan. 1999 3. S. Deering, “Host Extensions for IP Multicasting,” RFC 1112, Aug. 1989 4. C. Perkins, “IP Mobility Support,” RFC 2002, Oct. 1996 APCC : Wireless Internet Nov. 2, 2000
Internet Host Mobility Support • Prerequisite • sender may (need) not know the destination is moving • datagrams are routed based on IP address • Mobile IP • aims to allow transparent routing of datagrams to mobile hosts in the Internet • Three protocol steps • agent discovery • location registration • datagram tunneling APCC : Wireless Internet Nov. 2, 2000
Tunneling {MH k, MA s} Registration {MH k, MA s} Discovery MH k MH k MH k MH k MH k MH k {MH k, MA s} Triangle Routing Internet MA a MA p MA s MA k {MH a, *} {MH k, *} {MH k, -} MH a APCC : Wireless Internet Nov. 2, 2000
Multicasting • Transmitting the same information to a selective set of destination • aims to resource saving by arranging for network links to be shared • Two building blocks • membership management : IGMP • multicast routing protocol : DVMRP, CBT, PIM • DVMRP • composes a multicast tree of the reverse shortest paths from each destination to the source APCC : Wireless Internet Nov. 2, 2000
MR MR MR MR MR MR MR MR MR Membership query and reply graft Membership query and reply prune IGMP & DVMRP APCC : Wireless Internet Nov. 2, 2000
Tunnel Convergence Problem • When multicasting meets Internet host mobility support MR MA_a MA_s MA_k MH_s2 MH_a MH_s1 APCC : Wireless Internet Nov. 2, 2000
In Addition, • With mobility, delay and disconnection received twice MA i MH i1 orphan packet MH k1 MA k MH k2 partially received MH k3 disconnection partially received MA n not received MA p APCC : Wireless Internet Nov. 2, 2000
Arup’s Approach • Deliver datagrams to all subnets • do not need to rebuild the multicast tree for host moves MR MA_a MA_s MA_k MH_s2 MH_a MH_s1 APCC : Wireless Internet Nov. 2, 2000
Designated Tunneling server Designated Tunneling server Vineet’s Approach • Designated multicast service server • tried to resolve the tunnel convergence problem MR MA_a MA_s MA_k MH_s2 MH_a MH_s1 APCC : Wireless Internet Nov. 2, 2000
Host Mobility Locality • Boring professor model Computing Center (1/2 day) Computing Science (4 days) Company (1 day) APCC : Wireless Internet Nov. 2, 2000
Basic Idea • Find just the places where it is highly likely to be effectively utilized for packet routing • Local region for each mobile host • a set of subnets which the mobile host moves often • as a technical definition, a set of subnets that are visited by the host during the most recent time, t • then, our approach is to keep multicast paths for each of these subnets during t • as a result, the multicast routes may remain unchanged upon the host’s move, as long as the host moves around within the local region APCC : Wireless Internet Nov. 2, 2000
Local Region MR HA_a HA_s MA_k MH_s2 MH_a MH_s1 Local Region for MH_a APCC : Wireless Internet Nov. 2, 2000
Protocol Overview • Each MA maintains a group view table • <group_id, {mh, life_time, forwarding_time}> • Each MH maintains a group view list • <group_ids> • Each subnet within a local region maintains the corresponding group view table until the life_time expires • When a host moves out its local region, the previous MA forwards in-flight datagrams to current MA until the forwarding_time expires APCC : Wireless Internet Nov. 2, 2000
Handoff Procedure Current MA Previous MA MH HA Registration Req. Registration Rep. Compares {MH’s gourp list, MA’s group view} Forwarding Req. Multicast tree join period Starts Join operation Forwarding Rep. Refreshes forwarding_time Forwarding period from the previous MA Finish Join operation Expire forwarding_time Creates MH’s group view APCC : Wireless Internet Nov. 2, 2000
Summary • Internet multicast supporting host mobility brings new challenges as: • tunnel convergence • triangle routing • delivery semantics: not, duplicated, partial • orphan packet APCC : Wireless Internet Nov. 2, 2000