Traffic Measurement and Modeling in IP multicast Wenbo Liu Wenbo Liu Communication Laboratory, HUT Supervistor : Seppo J Halme Supervistor : Seppo J Halme Instructor: Tapani Nieminen

Content  Background Information Mutlticast, Unicast, Broadcast IGMP, Mbone, Multicast Routing Protocols  Practical Task IP Mulitast traffic measurement, observation and modeling

Multicast

Multicast Vs Broadcast,Unicast   At multicast, one host sending packet to multiple selected destination (group of hosts). -Class D ( ~ ) -Point-to-multipoint. -Join or leave multicast group anytime, anywhere. -Probably hosts may belong to various kinds of network type.

 Unicast is one source host sending packet to one destination host. -Point-to-point.-Non-real-time. -Best-effort-delivery service of IP.  At B roadcast, a host transmitting a packet to all attached hosts.  Even simpler than unicast for the application to implement

IGMP  Use IGMP message to join Multicast group  Internet Group Management Protocol  It allows hosts to communicate their desired group memberships to their local router memberships to their local router  The Internet Group Management Protocol (IGMP) is used by IPv4 system(hosts and routers) to report their IP multicast group memberships to any neighboring multicast router  IGMP v1 is defined RFC1112  IGMP v2 is defined RFC2236  IGMP v3 is defined RFC2933  IP Datagram: IP hearder (20 Bytes) + IGMP Message (8 Bytes)

Mbone  Internet Multicast Backbone  Mbone is a virtual network, it is layered on top of part of the physical Internet to support routing of IP multicast packet.  Virtual point-to-point links is called ’Tunnels’  With Mbone, a single packet can have multiple desinations

Multicast Routing Protocols Dense ModeSparse Mode Distance Vector Link StateShared Tree DVMRPPIM-DMMOSPFPIM-SMCBT Multicast Routing Protocols  DVMRP- Distance Vector Multicast Routing Protocol PIM-DM- Protocol Independent Multicast, Desnse Mode  MOSPF- Multicast Open Shorest Path First  PIM-SM- Protocol Independent Multicastt Sparse ModeCBT-Core Based Tree

Interoperability and Delivery   Interoperability between existing unicast and emerging multicast-capable routers.   Interoperability between the various approaches to multicast routing.   Data-driven Muliticast, Broadcast and prune strategy. Send data untill the destination do not want to get more. .  Demand-driven Multicast, Router joins to forwarding tree before datagrams has transfered to destination finished already in its network.

Measurement, Observations of IP multicast  The basic measurement of IP multicast is generated between Otaverkko and Funet.  Tcpdump program, SDR softwre are used during this task.  Tcpdump is a network-monitoring program, that can dump traffic on the network.  Case Study: Resource: tilt-gw.mediapoli.fi Destination: OSPF-ALL.MCAST.net or other destination multicast host. other destination multicast host.

16:35: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet: S : (0) win 8192 (DF) 16:35: alpha.hut.fi.telnet > tilt-mc2.mediapoli.com.1924: : (0) ack win (DF)5: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet:. ack 1 win 8760 (DF) 16:35: alpha.hut.fi.3907 > tilt-mc2.mediapoli.com.auth: S : (0) win (DF) 16:35: tilt-mc2.mediapoli.com.auth > alpha.hut.fi.3907: R 0:0(0) ack win 0 16:35: alpha.hut.fi.telnet > tilt-mc2.mediapoli.com.1924: P 1:16(15) ack 1 win (DF) [tos 0x10] 16:35: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet: P 1:4(3) ack 16 win 8745 (DF) 16:35: :0:1d:b0:16:ce 1:0:1d:0:0:0 81fd 75: f f d e00 001d d e00 001d b016 b d b016 b d f f :35: alpha.hut.fi.telnet > tilt-mc2.mediapoli.com.1924:. ack 4 win (DF) [tos 0x10] 16:35: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet: P 4:16(12) ack 16 win 8745 (DF) 16:35: alpha.hut.fi.telnet > tilt-mc2.mediapoli.com.1924: P 16:22(6) ack 16 win (DF) [tos 0x10] 16:35: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet: P 16:27(11) ack 22 win 8739 (DF) 16:35: alpha.hut.fi.telnet > tilt-mc2.mediapoli.com.1924: P 22:37(15) ack 27 win (DF) [tos 0x10] 16:35: tilt-mc2.mediapoli.com.1924 > alpha.hut.fi.telnet: P 27:30(3) ack 37 win 8724 (DF) 16:35: tilt-mc2.mediapoli.com.netbios_ns > tltnt10.hut.fi.netbios_ns: udp 50 16:35: alpha.hut.fi.telnet > tilt- mc2.mediapoli.com.1924:. ack 30 win (DF ) [tos 0x10]

IP Mulitcast Application –SDR software  SDR is session direction tool, which means that it lists session to be multicast on the Mbone rather than programmers broadcast on radio and TV  At SDR, the subscriber can creat session join existing one and choose some parameters.  This tool choose free Multicast addresses and ports