Symptom
After performing upgrade from 5.3.3 to 6.4.2, customer noticed the IPv6 traffic was not transiting this router which got upgraded.
Further checking ISIS database, we observed below. We had overload bit set for IPv6 Unicast alone, but not for the main LSP.
RP/0/RP0/CPU0:pop-crs-2-as65324#sh isis data pop-crs-2-as65324.00-00 det
Tue Mar 26 19:26:24.097 EST
IS-IS 65324 (Level-2) Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
pop-crs-2-as65324.00-00* 0x000051ca 0xaaf9 932 0/0/0 <<<
Area Address: 49.0001
Metric: 10 IP 172.16.11.0/31
NLPID: 0xcc
NLPID: 0x8e
IP Address: 172.16.11.1
Hostname: pop-crs-2-as65324
MT: Standard (IPv4 Unicast)
MT: IPv6 Unicast 0/0/1 <<<
IPv6 Address: 2001:1998:212::2
Metric: 10 MT (IPv6 Unicast) IPv6 2001:1998:210:4::34:4/127
Metric: 0 MT (IPv6 Unicast) IPv6 2001:1998:212::2/128
Conditions
This bug is only applicable to router running 6.4.2 release(fix committed to other releases are enhancement for show commands, etc).. Router reload from software upgrade
