Multicast Networking

2 References Multicast Networking and Applications Miller, C. Kenneth Addison-Wesley, 1999 Computer Networking: A Top-Down Approach Featuring the Internet James F. Kurose, Keith W. Ross RFC

3 Introduction Unicast protocols Multicast protocols From one or more senders to a group of receivers bulk data, streaming continuous media, shared data applications, data feeds, interactive gaming

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5 Multicast applications

6 Multicast group address indirection class D ~

7 IPv6 128 bits flgs: three higher-order bits are set to zero scop: 0~F

8 Multicast address allocation

9 Network layer multicast protocol IGMP Multicast routing protocol Transport layer multicast protocol Reliable multicast protocol

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11 IGMP Joining particular multicast group is receiver-initiated using the Internet Group Management Protocol (IGMP) A dialog that occurs between routers supporting multicast routing and hosts on a subnet attached to that router

12 IGMP v1 RFC 1112 Nearest router Query messages Periodically from router to hosts Time To Live of 1 Membership reports from hosts Random back-off to avoid report messages implosion

13 IGMP v2 RFC 2236 Membership query General group Specific group Membership report Leave group

14 IGMP v3 Internet draft Select only specific sources of multicast traffic to receive Inclusion group-source report messages Exclusion group-source report messages Leave group messages Specify the IP addresses of any source-group pairs it wishes to leave

15 Multicast Routing Protocols Group-shared tree Steiner tree problem Source-based tree Distance vector Link state Shared tree

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17 DVMRP RFC 1075 Distance vector algorithm Reverse path forwarding(RPF) Pruning grafting

18 MOSPF RFC 1584 Link-state advertisements Complete topology information Edge routers with attached hosts belonging to various multicast groups

19 Protocol Independent Multicast-Dense Mode Internet draft Flood-and-prune Similar to DVMRP Protocol independent

20 Core-Based Trees RFC 2201,2189 Single core Join JOIN_REQUEST JOIN_ACK Maintain ECHO_REQUEST ECHO_REPLY

21 Protocol Independent Multicast-Sparse Mode RFC 2117 Rendezvous point Encapsulate data and unicast to the RP Switch from a group-shared tree to a source-specific tree

22 Interdomain Multicast Routing Interior gateway protocol (IGP) Exterior gateway protocol (EGP) Border Gateway Multicast Protocol (BGMP) Internet draft Group-shared tree approach Set up roots by MASC

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24 Wide Area Networks Asynchronous transfer mode Meshes of point-to-multipoint PVCs ATM-level multicast servers (MCS)

25 One-way satellite

26 TCP : point-to-point (unicast) UDP : multicast Reliable Multicast Technology

27 Research Activities and Topics in Reliable Multicast Request implosion Duplicate replies Recovery latency Recovery isolation (exposure) Adaptability to dynamic membership change

28 Reliable Multicast Protocols Create a generalized reliable multicast transport layer that can handle all reliable multicast applications timeliness, packet ordering, error correction, high scalability Focus the reliable multicast protocol on solving the needs of particular applications

29 Generalized Reliable Multicast Protocols Scalable Reliable Multicast (SRM) Repair by any receiver that has the data to achieve scalability by reducing administrative back-traffic to the source Suppression of duplicate requests via a random time period A random back-off timer is used before a repair is sent

30 No scope limit (exposure)

31 Reliable Multicast Transport Protocol (RMTP) Designated Receivers (DRs) Collect status messages from nodes in a local RMTP domain Provide repairs RMTP+ Transmit window Bit mask (selective repeat retransmission)

32 RMTP

33 Specialized Reliable Multicast Protocols Reliable Adaptive Multicast Protocol (RAMP) Group sizes less than 100, timeliness RFC 1458 Break up the data sent into bursts Burst mode Idle mode

34 Multicast File Transfer Protocol (MFTP) Internet draft NAK-based Block as large as possible