IP
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... The Internet Group Management Protocol (IGMP) is used by IP hosts to
report their multicast group ...
... Like ICMP, IGMP is a integral part of IP. It is required to be
implemented by all hosts wishing to receive IP multicasts ...
... IP. It is required to be
implemented by all hosts wishing to receive IP multicasts. IGMP
messages are encapsulated in IP datagrams ...
... IP multicasts. IGMP
messages are encapsulated in IP datagrams, with an IP protocol number
of 2. All IGMP messages ...
... IGMP
messages are encapsulated in IP datagrams, with an IP protocol number
of 2. All IGMP messages described in this document are sent with IP
TTL ...
... IP protocol number
of 2. All IGMP messages described in this document are sent with IP
TTL 1, and contain the IP Router Alert option [RFC2113 ...
... of 2. All IGMP messages described in this document are sent with IP
TTL 1, and contain the IP Router Alert option [RFC2113] in their IP
header ...
... IP Router Alert option [RFC2113] in their IP
header. All IGMP messages of concern to hosts have the following
...
... bit one's complement of the one's complement
sum of the whole IGMP message (the entire IP payload). For computing
the checksum, the checksum field ...
... Group message, the group address
field holds the IP multicast group address of the group being
...
... IGMP checksum is always computed over the whole IP payload, not just
over the first 8 octets.
...
... Query message from a router with a lower IP address, it MUST become a
Non-Querier on that network ...
... Version 2 Membership
Report to the group, with IP TTL of 1. If the host receives another
host ...
... state transition
diagram below. A host may be in one of three possible states with
respect to any single IP multicast group on any single network
interface:
...
... timer set to
note the presence of another querier with a lower IP address on the
network expires.
...
... router with a lower | | present timer
IP address | | expired
(set other querier | ________________ | (send general
...
... groups have members, a router may
be in one of four possible states with respect to any single IP
multicast group on any single attached network:
...
...
A forged Query message from a machine with a lower IP address than
the current Querier will cause Querier ...