A customer discovered that some subscriber connected to MDU(MA5652G) have multicast stream freeze problem, to find out the cause they configured traffic mirror for vlan8(multicast vlan) on the uplink port on OLT, then the problem disappeared.
When the traffic mirror is deleted, the problem happens again.
Matches: Acl 4000 rule 5 running
Mirror to: port 0/20/1
OLT version: MA5600V800R005C32B150HP0001
1. Confirmed that this problem happens to all customers, no matter connected to MDU or ONT.
2. Confirmed that this problem happens to all programs configured.
3. According to above analysis, tried to disable multicast traffic suppress, problem solved.
There is a unknown multicast traffic suppress configured by default by the OLT which can be displayed with command:
MA5600T(config-if-giu-0/19)#display traffic-suppress all
Since this customer use double tagged vlan for multicast traffic, the OLT will broadcast these packets to GPBC boards as unknown multicast packets and thus affected by the suppress parameter.
The unknown multicast traffic suppress function is realized by acl 4000 rule ffff, and mirror function is also configured with acl 4000 rule 5, whose rule is permit with action mirror.
since the last configured rule will take effect first, so this mirror function permits all the traffic flow and the packets will not be discarded.
Disable multicast traffic suppress manually:
MA5600T(config-if-giu-0/19)#undo traffic-suppress 0 multicast