[f-nsp] ANY IDEAS - IP6 multicast traffic causing severe CPU load issue (on ICX)

[Justin Keery]

Hi folks, any ideas about this?

The switches affected by this include ICX6540, 6610 and 6650 all of which
were involved in transporting the VLAN described below.

IP6 multcast traffic (less than 20Mbit/sec, discovered with wireshark on a
mirror port) on VLAN682 was causing >40% CPU load on all switches where
this VLAN was configured, even though there is no IP virtual interface in
this VLAN. At one point there was a brief but serious OSPF failure whilst
this condition was present.

With the ingress port shut down the CPU load returned to 1%.

We tried to disable IP4 and IP6 igmp / mld snooping, this had no effect. We
then added a router-interface so we could add an IP6 ACL to filter *all*
IP6 traffic - again no effect

vlan 682 name KARMARAMA_L2_ONEA809159_682 by port
 tagged ethe 1/2/1 to 1/2/3
 router-interface ve 682 <- added later so we could implement an ACL
 multicast disable-igmp-snoop <- did not help
 multicast6 disable-mld-snoop <- did not help

*We need a way to make sure that IP6 multicasts on a VLAN won't overload
the CPU on any switch with that VLAN present - ideally filter that VLAN
from the CPU altogether!*

Any ideas?

Thanks

Justin
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