Verifying Multicast Mcache for Multicast Groups which Share the Same Multicast MAC Address (IGMP snooping)
If there are two multicast groups
(225.1.1.1 and 234.1.1.1) which map to the same multicast MAC address, the
show ip multicast mcache
command output for one of the groups will be empty. Note: These steps are to be used when
snooping is MAC-based for IPv4. IGMP snooping is MAC-based for the ICX 7150-C08
device, but it is IP-based for all other devices.
- Get the mapped multicast MAC
address for the interested multicast group (use 23 as the bit value for an exact
match).
device# show ip multicast group 234.1.1.1 match-last-bits 23 Display groups sharing same mac address 0100.5e01.0101 with group 234.1.1.1 for all vlans on all ports. p-:physical, ST:static, QR:querier, EX:exclude, IN:include, Y:yes, N:no VL4089 : 11 groups, 23 group-port group p-port ST QR life mode source 1 234.1.1.1 lg1 no yes 240 EX 0 2 234.1.1.1 e1/1/8 no yes 260 EX 1 3 225.1.1.1 lg1 no yes 240 EX 0 4 225.1.1.1 e1/1/8 no yes 260 EX 1 - Using the multicast MAC address
( 0100.5e01.0101), get the multicast group address with which the mcache is
programmed.
device# show ip multicast mac-mcache 0100.5e01.0101 Example: MAC = xxxx.xxxx.xxxx Vlan = #, l2mc = # , ref_cnt = # IP Multicast Group : Mcast Group, Src Addr OIF: 1/1/22 TR(1/1/32,1/1/33), TR is trunk, 1/1/32 primary, 1/1/33 output Total Multicast Mac Cache: 1 vlan 4089, 10 caches 1 MAC=0100.5e01.0101, vlan=4089, l2mc=257, ref_cnt=1 IP Multicast Group (* 225.1.1.1) OIF: 1/1/2 1/1/8 lg1 Total Multicast Mac Cache: 1 - Verify whether the multicast
mcache is present for the multicast group 225.1.1.1.
device# show ip multicast mcache 225.1.1.1 Example: (S G) (MAC ADDR) cnt=: SRC and GRP IPv4/IPv6 address, Multicast Mac address, cnt is number of SW processed packets OIF: 1/1/22 TR(1/1/32,1/1/33), TR is trunk, 1/1/32 primary, 1/1/33 output IPv4 Multicast Forwarding Mode: MAC Total Multicast Cache: 10 vlan 4089, 10 caches. 1 (* 225.1.1.1) (0100.5e01.0101) cnt=226 OIF: tag e1/1/2 tag e1/1/8 tag lg1 age=26s up-time=141s, change=141s l2mc=257 (ref-cnt=1