3Com 4200G 12-Port Configuration Manual

Also see for 3CR17660-91: Quick reference guide Datasheet

Contents

3Com 4200G 12-Port Configuration Manual Manual pdf 263 page image

29 IGMP SNOOPING CONFIGURATIONOverview of IGMPSnoopingIGMP SnoopingFundamentalsIGMP Snooping (Internet Group Management Protocol Snooping) is a multicastcontrol mechanism running on Layer 2 switch. It is used to manage and controlmulticast groups.When the IGMP messages transferred from the hosts to the router pass through theLayer 2 switch, the switch uses IGMP Snooping to analyze and process the IGMPmessages.By listening to IGMP messages, the switch establishes and maintains MAC multicastaddress tables at data link layer, and uses the tables to forward the multicast packetsdelivered from the router.As shown in Figure 79, multicast packets are broadcasted at Layer 2 when IGMPSnooping is disabled and multicasted (not broadcasted) at Layer 2 when IGMPSnooping is enabled.Figure 79 Multicast packet transmission with or without IGMP SnoopingTable 219 IGMP message processing on the switchReceived messagetype Sender Receiver Switch processingIGMP host reportmessageHost Switch Add the host to the correspondingmulticast group.IGMP leave message Host Switch Remove the host from the multicastgroup.InternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo stream Video streamVideo streamMulticastgroup member Non-multicastgroup memberNon-multicastgroup memberVideo streamVideo streamInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo streamMulticastgroup member Non-multicastgroup memberNon-multicastgroup memberVideo streamVideo streamMulticast packet transmissionwithout IGMP SnoopingMulticast packet transmissionwith IGMP SnoopingInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberMulticast packet transmissionwithout IGMP SnoopingInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo stream Video streamVideo streamMulticastgroup member Non-group memberNon-group memberVideo streamVideo streamInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo streamMulticastgroup member Non-group memberNon-group memberVideo streamVideo streamMulticast packet transmissionwithout IGMP SnoopingMulticast packet transmissionwith IGMP SnoopingInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberMulticast packet transmissionwithout IGMP SnoopingInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo stream Video streamVideo streamMulticastgroup member Non-multicastgroup memberNon-multicastgroup memberVideo streamVideo streamInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo streamMulticastgroup member Non-multicastgroup memberNon-multicastgroup memberVideo streamVideo streamMulticast packet transmissionwithout IGMP SnoopingMulticast packet transmissionwith IGMP SnoopingInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberMulticast packet transmissionwithout IGMP SnoopingInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo stream Video streamVideo streamMulticastgroup member Non-group memberNon-group memberVideo streamVideo streamInternetVideo stream VOD serverLayer 2 Ethernet sw itchMuliticast routerVideo streamMulticastgroup member Non-group memberNon-group memberVideo streamVideo streamMulticast packet transmissionwithout IGMP SnoopingMulticast packet transmissionwith IGMP SnoopingInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberInternetVideo streamMuliticastMulticastgroup member Non-group memberNon-group memberMulticast packet transmissionwithout IGMP Snooping