Cabletron Systems SmartSwitch 6E122 Supplement Manual

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Cabletron Systems SmartSwitch 6E122 Supplement Manual Manual pdf 75 page image

IGMP/VLAN Configuration ScreenLocal Management Supplement1-57The 802.1Q VLAN Configuration Menu screen displays 6 menu items,including the following new menu item:IGMP/VLAN CONFIGURATIONUsed to enable or disable IGMP (Internet Group Management Protocol)on selected VLANs. For details, refer to Section 1.23.1.23 IGMP/VLAN CONFIGURATION SCREENThe IGMP/VLAN Configuration screen, Figure 1-22, allows the user toenable or disable IGMP (Internet Group Management Protocol,RFC 2236) on selected VLANs.IGMP provides a solution for handling multicast streams in layer 2switching devices. IGMP is for hosts on multi-access networks to informlocally attached switches of their Multicast group membershipinformation. This is performed by hosts multicasting IGMP HostMembership Reports. Multicast switches listen for these messages andthen pass them to routers. This allows distribution trees to be formed todeliver multicast datagrams.Information from the IGMP packets is used to send the multicast streamonly to the end stations that request it. IGMP is enabled or disabled byVLAN, not port-by-port.The following multicast routing protocols are transparently supported andare used only to detect the location of routers (see the Release Notes forany changes or additions to this list):• DVMRP (Distance Vector Multicast Routing Protocol, RFC 1075)• PIM (Protocol Independent Multicast) version 1 and 2• CBT (Core Based Trees)• MOSPF (Multicast OSPF, RFC 1583)NOTECertain versions of firmware will not allow the switch to be aquerier. Please check your release notes for furtherinformation. Refer to RFC 2236, Section 8, for moreinformation on IGMP, and also Appendix A.