[j-nsp] IPv6 MTU issue

[Gökhan Gümüş]

Dear all,

I have an issue with IPv6 MTU.

When i make a traceroute to one destination, the MTU size is reduced from
1500 to 1496, somehow...?

What makes it worse is that hop which drops the MTU does not send ICMP
"packet too long" message back..

gg# scamper -I "trace -P udp -M abc
traceroute from xxx to abc
 1  s  0.192 ms [mtu: 1500]
 2  d  0.356 ms [mtu: 1500]
 *3  f  1.422 ms [mtu: 1500]*
*  4  g  1.107 ms [*mtu: 1496]*
 5  h  1.145 ms [*mtu: 1496]


On the link where MTU drops, output is as follows,

 Protocol inet, MTU: 1500

 Protocol inet6, MTU: 1500



Software version is 10.0R4.7.



Anybody has an experience on this behaviour before.



Thanks and regards,

Gokhan