CSCvk32439 - IPv6 - SISF main thread consumes high CPU DHCPv6/ICMPv6 SOLICIT - 4

[enyamutenha]

I can confirm that we are hitting this bug on a Cisco C9500-40X software version 16.6.4. I had both IPv6 and DHCP Snooping turned on; turned them both off and CPU dropped to normal levels. I still have a use case for IPv6 and DHCP snooping so I'm eagerly awaiting a fix.

[Riley3]

It is affecting our C9300-48P running 16.6.5 also.

[radics.tibor1974]

9200L with version 17.3.1, 17.3.2a hiting this BUG also.

[Stepan Vesely]

Old 2960G (12.2(55)SE12; 12.2(58)SE2...etc) hitting this bug too, when using switches like new 9200L in same network which sending ICMPv6, DHCPv6 packets.

9200L version 17.3.3 hitting too.

When using 2960 as main switch on building, access switch after this switch dont have high CPU. 

Not using "ip dhcp snooping" help fix this problem on 9200L to me, but not same on 2960.