IP Multicast Service Model(Cont Many-to-many k Not only one-to-many No central state 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. 2021/2/11
IP Multicast Service Model (Cont.) Many-to-many Not only one-to-many No central state 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. 2021/2/11 12
IP Multicast Group Address * IPv4 Multicast Group Addresses *224.00.0-239255.255.255 Class "D"Address space High order bits of 1st octet =1110 Reserved Link-local Addresses *22400.0-224.00.255 k transmitted with ttl 1 Examples 224.0.0.1 All systems on this subnet 224.0.0.2 All routers on this subnet 224.0.0 4 DVMRP routers *224.005 OSPF routers k 224.0.0.13 PIMv2 routers 2021/2/11 13
IP Multicast Group Address IPv4 Multicast Group Addresses 224.0.0.0–239.255.255.255 Class “D” Address Space High order bits of 1st Octet = “1110” Reserved Link-local Addresses 224.0.0.0–224.0.0.255 Transmitted with TTL = 1 Examples: 224.0.0.1 All systems on this subnet 224.0.0.2 All routers on this subnet 224.0.0.4 DVMRP routers 224.0.0.5 OSPF routers 224.0.0.13 PIMv2 routers 2021/2/11 13
IP Multicast Group Address(Cont Administratively scoped Addresses *23900.0-239.255.255.255 Private address space k similar to rFc1918 unicast addresses k not used for global Internet traffic k Used to limit scope of multicast traffic Same addresses may be in use at different locations for different multicast sessions Examples k Site-local scope: 239.253.0.0/16 Organization-local scope: 239. 192.0.0/14 2021/2/11 14
IP Multicast Group Address (Cont.) Administratively Scoped Addresses 239.0.0.0–239.255.255.255 Private address space Similar to RFC1918 unicast addresses Not used for global Internet traffic Used to limit “scope” of multicast traffic Same addresses may be in use at different locations for different multicast sessions Examples Site-local scope: 239.253.0.0/16 Organization-local scope: 239.192.0.0/14 2021/2/11 14
IP Multicast MAC Address Mapping 32 Bits 1110 28 Bits 239.2550.1 5 Bits Lost 01005e-710001 25 Bits 23 Bits 48 Bits 2021/2/11 15
IP Multicast MAC Address Mapping 2021/2/11 15 32 Bits 28 Bits 25 Bits 23 Bits 48 Bits 01-00-5e-7f-00-01 1110 5 Bits Lost 239.255.0.1
IP Multicast APl Sender-same as before Receiver-two new operations k Join(group) k Leave(group) Receive multicast packets for joined groups via formal IP-Receive operation k Implemented using socket options 2021/2/11
IP Multicast API Sender – same as before Receiver – two new operations Join(group) Leave(group) Receive multicast packets for joined groups via normal IP-Receive operation Implemented using socket options 2021/2/11 16