Cisco SR224T Administration Guide - Page 193

Configuring Multicast Forwarding Defining Multicast Properties 15 The following versions are supported: • IGMP v1/v2/ v3 • MLD v1/v2 Multicast Address Properties Multicast addresses have the following properties: • Each IPv4 Multicast address is in the address range 224.0.0.0 to 239.255.255.255. • The IPv6 Multicast address is FF00:/8. • To map an IP Multicast group address to an Layer 2 Multicast address: - For IPv4, this is mapped by taking the 23 low-order bits from the IPv4 address, and adding them to the 01:00:5e prefix. By standard, the upper nine bits of the IP address are ignored, and any IP addresses that only differ in the value of these upper bits are mapped to the same Layer 2 address, since the lower 23 bits that are used are identical. For example, 234.129.2.3 is mapped to a MAC Multicast group address 01:00:5e:01:02:03. Up to 32 IP Multicast group addresses can be mapped to the same Layer 2 address. - For IPv6, this is mapped by taking the 32 low-order bits of the Multicast address, and adding the prefix of 33:33. For example, the IPv6 Multicast address FF00:1122:3344 is mapped to Layer 2 Multicast 33:33:11:22:33:44. Defining Multicast Properties The Properties page enables you to configure the Bridge Multicast filtering status. By default, all Multicast frames are flooded to all ports of the VLAN. To selectively forward only to relevant ports and filter (drop) the Multicast on the rest of the ports, enable Bridge Multicast filtering status in the Properties page. If filtering is enabled, Multicast frames are forwarded to a subset of the ports in the relevant VLAN as defined in the Multicast Forwarding Data Base. Multicast filtering is enforced on all traffic. By default, such traffic is flooded to all relevant ports, but you can limit forwarding to a smaller subset. Cisco Small Business 200 Series Smart Switch Administration Guide 194