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Internet Group Management Protocol
(IGMP)
Internet group management protocol (IGMP) is a Layer 3 multicast protocol that hosts use to join or leave
a multicast group.
Multicast is premised on identifying many hosts by a single destination IP address; hosts represented by
the same IP address are a multicast group. Multicast routing protocols (such as protocol-independent
multicast [PIM]) use the information in IGMP messages to discover which groups are active and to
populate the multicast routing table.
IGMP Implementation Information
• Dell Networking Operating System (OS) supports IGMP versions 1, 2, and 3 based on RFCs 1112, 2236,
and 3376, respectively.
• Dell Networking OS does not support IGMP version 3 and versions 1 or 2 on the same subnet.
• IGMP on Dell Networking OS supports 95 interfaces on S4810 and S4820 and an unlimited number of
groups on all other platforms.
• Dell Networking systems cannot serve as an IGMP host or an IGMP version 1 IGMP Querier.
• Dell Networking OS automatically enables IGMP on interfaces on which you enable a multicast
routing protocol.
IGMP Protocol Overview
IGMP has three versions. Version 3 obsoletes and is backwards-compatible with version 2; version 2
obsoletes version 1.
IGMP Version 2
IGMP version 2 improves on version 1 by specifying IGMP Leave messages, which allows hosts to notify
routers that they no longer care about traffic for a particular group.
Leave messages reduce the amount of time that the router takes to stop forwarding traffic for a group to
a subnet (leave latency) after the last host leaves the group. In version 1 hosts quietly leave groups, and
the router waits for a query response timer several times the value of the query interval to expire before it
stops forwarding traffic.
To receive multicast traffic from a particular source, a host must join the multicast group to which the
source is sending traffic. A host that is a member of a group is called a receiver. A host may join many
groups, and may join or leave any group at any time. A host joins and leaves a multicast group by sending
an IGMP message to its IGMP Querier. The querier is the router that surveys a subnet for multicast
receivers and processes survey responses to populate the multicast routing table.
IGMP messages are encapsulated in IP packets, as shown in the following illustration.
354
Internet Group Management Protocol (IGMP)
Содержание S6000-ON
Страница 1: ...Dell Configuration Guide for the S6000 ON System 9 9 0 0 ...
Страница 505: ...Figure 60 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 505 ...
Страница 508: ...Figure 62 Inspecting a LAG Port on BRAVO Using the show interface Command 508 Link Aggregation Control Protocol LACP ...
Страница 509: ...Figure 63 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 509 ...
Страница 552: ...mac address table static multicast mac address vlan vlan id output range interface 552 Microsoft Network Load Balancing ...
Страница 557: ...Figure 80 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 557 ...
Страница 558: ...Figure 81 Configuring PIM in Multiple Routing Domains 558 Multicast Source Discovery Protocol MSDP ...
Страница 562: ...Figure 83 MSDP Default Peer Scenario 1 562 Multicast Source Discovery Protocol MSDP ...
Страница 563: ...Figure 84 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 563 ...
Страница 564: ...Figure 85 MSDP Default Peer Scenario 3 564 Multicast Source Discovery Protocol MSDP ...
Страница 665: ...Policy based Routing PBR 665 ...
Страница 672: ...ip pim bsr border Remove candidate RP advertisements clear ip pim rp mapping 672 PIM Sparse Mode PIM SM ...
Страница 818: ...Figure 110 Single and Double Tag TPID Match 818 Service Provider Bridging ...
Страница 819: ...Figure 111 Single and Double Tag First byte TPID Match Service Provider Bridging 819 ...
Страница 995: ...Figure 140 Setup OSPF and Static Routes Virtual Routing and Forwarding VRF 995 ...