Ticket Number: HEA-NOC/20040519-11 Ticket Status: UPDATE
Ticket Type: unscheduled Resolver: HEA-NOC
Ticket Opened: 20040519 12:11 UTC+1 Problem Start: 20040519 12:00 UTC+1
Ticket Update: 20040723 14:51 UTC+1 Problem End:
There is intermittent IPv6 packet loss on the network backbone.
Causes netsaint to log errors as packets are dropped.
20040519 12:08 JL
Investigations have shown that packet loss is indeed present and is
unlikely to be a problem with netsaint. First change to be made was ICMP
error interval which was added to all routers. Errors still there. During
investigation it was noticed that IPV6 CEF wasnt switched on on many of
our routers so stopping forwarding in FIB and subsequently hardware.
Preparing list of routers which need CEF enabled.
20040520 12:10 JL
IPv6 CEF needs to be enabled on Andel, Salinger, Leabhair, Tempus &
Lucien. Will add IPv6 cef to these routers on Wednesday 26th 09:00 during
20040524 12:22 JL
IPv6 CEF to be enabled on all routers listed, should not be service
20040526 09:11 JL
IPv6 CEF enabled on the listed routers. Monitoring performance.
20040611 10:14 JL
Enabling IPv6 has not fixed the problem. Further investigation has showed
that each of the links being pinged is taking a similiar route through the
Netsaint alarms are also occurring for the three problem links in 12 hour
intervals. Continuing to investigate.
20040615 10:36 CMC More ping6 alarms observed, however experimentation
reveals that a traceroute6 brings the path alive again however a ping6
does not. ICMP with incrementing ttl's was tried and also had no effect,
looks like a genuine UDP Vs ICMP difference.
20040616 17:17 CMC More ping6 alarms observed. Confirm UDP Vs ICMP issue
using "nc6 -u". Verbose mail sent to [log in to unmask]
20040716 16:46 JL
Lancomms still investigating issue. Possible IOS upgrade needed on Dublin
20040720 11:10 CW escalating case after discussions with Cisco
20040723 14:15 CW making config changes under direction from Cisco TAC
20040723 14:46 CW Cisco identify bug (CSCec15559), due to linecard resets
some disruption to connectivity in the Dublin POP but traffic did divert
via the backup UBR path to Citywest.
This ticket can be monitored at http://www.hea.net/tickets/20040519-11