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Community Member

IS-IS and IPv6 in equal cost path topology

Network of 7609s running 12.2(18)SXE3. Two

equal cost path links between each 7609. IS-IS Level 2 routers only. When pinging an off campus IPv6 host every other packet is lost. It seems like the equal cost paths prevent an alternative path off campus but that path isn't working.

We cannot figure out where to look next.

Any thoughts ? Is this possibly an IS-IS

issue ?

Thanks

3 REPLIES
Cisco Employee

Re: IS-IS and IPv6 in equal cost path topology

It certainly looks like one of the two paths is not working properly. Could you please be a bit more descriptive about the path between the source and the destination in this scenario.

Thanks,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Community Member

Re: IS-IS and IPv6 in equal cost path topology

OK. I'll try. We have 5-7609s running 12.2(18)SXE3.

Each 7609 has a variety of 100/1000Base Ethernet

interfaces. They each also have one WS-X6704-10GE out

of which connections to our primary and secondary

backbones originate. This is how the routers are

interconnected.

Three of the five core routers are currently running

IS-IS. If we ssh into any router and ping

www.netbsd.org every other packet is lost.

At the end of the network are two 6506 switches each

with a 10GE module and a 1GE module.

Attached to the 1GE module are fiber links two

two different Juniper M10s which also run IS-IS

and through which we get upstream connectivity

to our provider.

All of our routers are level 2 routers in the same area.

Does this help? If not please let me know what else

you would need.

Thanks,Steve

Cisco Employee

Re: IS-IS and IPv6 in equal cost path topology

A traceroute should help in pinpointing which one of the two paths is not functioning properly.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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