D-Link DES-3326 - Manual (Page 58)

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
224.0.0.2 All Routers on this subnet
224.0.0.3 Unassigned
224.0.0.4 DVMRP Routers
224.0.0.5 OSPF IGP Routers
224.0.0.6 OSPF IGP Designated Routers
224.0.0.7 ST Routers
224.0.0.8 ST Hosts
224.0.0.9 All RIP2 Routers
224.0.0.10 All IGRP Routers
224.0.0.11 Mobile Agents
224.0.0.12 DHCP Servers and Relay Agents
224.0.0.13 All PIM Routers
224.0.0.14 RSVP Encapsulation
224.0.0.15 All CBT Routers
224.0.0.16 Designated Sbm
224.0.0.17 All Sbms
224.0.0.18 VRRP
224.0.0.19
through
224.0.0.225
Unassigned
224.0.0.21 DVMRP on MOSPF
Table 5-10. Reserved Multicast Address Assignment
Internet Group Management Protocol (IGMP)
End users that want to receive multicast packets must be able to inform nearby routers that they want
to become a multicast group member of the group these packets are being sent to. The Internet Group
Management Protocol (IGMP) is used by multicast routers to maintain multicast group membership.
IGMP is also used to coordinate between multiple multicast routers that may be present on a network
by electing one of the multicast routers as the ‘querier’. This router then keep track of the membership
of multicast groups that have active members on the network. IGMP is used to determine whether the
router should forward multicast packets it receives to the subnetworks it is attached to or not. A
multicast router that has received a multicast packet will check to determine if there is at least one
member of a multicast group that has requested to receive multicast packets from this source. If there
is one member, the packet is forwarded. If there are no members, the packet is dropped.
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