HP 6120XG HP ProCurve Series 6120 Blade Switches IPv6 Configuration Guide - Page 61
IPv6 Multicast Address Format, Multicast Group Identification
View all HP 6120XG manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 61 highlights
IPv6 Addressing Multicast Application to IPv6 Addressing IPv6 Multicast Address Format The multicast address format has three principal sections in the leading 16 bits: ■ identifier: ff (bits 1-8) ■ flags: 0xxx (bits 9-12) ■ scope: 0001 - 1110 (bits 13-16) For related information, refer to RFC 4291. Multicast Group Identification Multicast ID, Flags and Scope (16 bits) 1111 1111 0xxx xxxx : Group Identifier (112 bits) x...x : x...x : x...x : x...x : x...x : x...x : x...x ■ multicast identifier: The first eight high-order bits, set to ff, identify the address as multicast. ■ multicast flags: Bits 9-12 are multicast flags that provide additional information about the multicast address, as follows: Bit ID 9 10 (R) 11 (P) Options Use 0 reserved 0 multicast address without PIM-SM rendezvous point 1 multicast address with PIM-SM rendezvous point 0 multicast address without prefix information from the originating network 12 (T) 1 multicast address with prefix information from the originating network 0 multicast address is permanent (well-known, and not restricted by scope value) 1 multicast address is temporary (and used only within an identified scope) ■ multicast scope: Bits 13-16 set boundaries on multicast traffic distribution, such as the interface defined by the link-local unicast address of an area, or the network boundaries of an organization. Because IPv6 uses multicast technology in place of the broadcast technology used in IPv4, the multicast scope field also controls the boundaries for broadcast-type traffic sent in multicast packets. 3-22