P Multicast architecture Service model Hosts Host-to-router protocol (IGMP Routers Multicast routing protocols (various) Lecture11:10-3-2006
Lecture 11: 10-3-2006 6 IP Multicast Architecture Hosts Routers Service model Host-to-router protocol (IGMP) Multicast routing protocols (various)
Logical Naming Single name/address maps to logically related set of destinations Destination set multicast group Key challenge: scalability Single name/address independent of group growth or changes Lecture11:10-3-2006
Lecture 11: 10-3-2006 7 Logical Naming • Single name/address maps to logically related set of destinations • Destination set = multicast group • Key challenge: scalability • Single name/address independent of group growth or changes
Multicast Router responsibilities Learn of the existence of multicast groups (through advertisement) Identify links with group members Establish state to route packets Replicate packets on appropriate interfaces Routing entry Src, incoming interface List of outgoing interfaces Lecture11:10-3-2006
Lecture 11: 10-3-2006 8 Multicast Router Responsibilities • Learn of the existence of multicast groups (through advertisement) • Identify links with group members • Establish state to route packets • Replicate packets on appropriate interfaces • Routing entry: Src, incoming interface List of outgoing interfaces
P Multicast Service Model (rfc1112) Each group identified by a single IP address Groups may be of any size Members of groups may be located anywhere in the Internet Members of groups can join and leave at will Senders need not be members Group membership not known explicitly Analogy. Each multicast address is like a radio frequency, on which anyone can transmit, and to which anyone can tune-in Lecture11:10-3-2006
Lecture 11: 10-3-2006 9 IP Multicast Service Model (rfc1112) • Each group identified by a single IP address • Groups may be of any size • Members of groups may be located anywhere in the Internet • Members of groups can join and leave at will • Senders need not be members • Group membership not known explicitly • Analogy: • Each multicast address is like a radio frequency, on which anyone can transmit, and to which anyone can tune-in
P Multicast Addresses Class d IP addresses 224.0.0.0-239255.255.255 1110 Group ID How to allocated these addresses? Well-known multicast addresses assigned by lanA Transient multicast addresses assigned and reclaimed dynamically, e.g., by sdr program Lecture11:10-3-2006
Lecture 11: 10-3-2006 10 IP Multicast Addresses • Class D IP addresses • 224.0.0.0 – 239.255.255.255 • How to allocated these addresses? • Well-known multicast addresses, assigned by IANA • Transient multicast addresses, assigned and reclaimed dynamically, e.g., by “sdr” program 1 1 1 0 Group ID