IPv6 packet losses - 20% normal on traceroute6s?

[Pekka Savola]

On Sat, 2 Mar 2002, Michael Kjorling wrote:
> When I use the 6tap IPv6 traceroute service, it seems like I get a
> consistent some 20% packet loss. Pinging the same host from the same
> site does not show anywhere near this loss.
> 
> Even routers very close to 6tap's server (first and second hop shows
> one out of three dropped packets each) show this problem. Tracerouting
> back to 3FFE:700:20:3::1 (first hop from 6tap towards me), while not
> giving much information (only three hops being listen, as opposed to
> six the other way) still shows a rather consistent 33% loss between
> UUNet's router and 6tap's.
> 
> Is this considered normal?

This is most probably caused by hare-brained ICMP error rate-limiting; you 
can detect old Cisco's from the crowd as they drop about every other 
traceroute.  It has been fixed in recently released 12.2(8)T, and remedied 
in the ICMP6 draft standard candidate draft.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords