Juniper <-> Cisco IPv6 BGP peering

Randy Carpenter rcarpen at
Fri Dec 9 16:38:44 UTC 2011

----- Original Message -----
> On Thu, Dec 8, 2011 at 11:53 AM, Randy Carpenter
> <rcarpen at> wrote:
> > Tried that. I agree with others that it is an NDP issue. NDP for
> > the GUA is fine, but just not for the link local. Is there
> > something that would block only link local by default?
> >
> > I should add that I have another uplink to a different provider
> > that works perfectly. The other end is Juniper for that one.
> Just to begin with:
> 0) Does your Juniper device have the neighbor cache entry for Cisco
> link-local address? What is the state of the entry?

Sometimes it does, sometimes I can't seem to get it.

> Can you get packet capture on both sides?

We have done this.
> 1) is Cisco sending NS packets?


> 2) is your Juniper receiving them?

It does not appear to. Tracing v6 stuff on juniper seems to be hit or miss.

> 3) is Juniper device sending anything back?

No. (because of #2)

> 4) are those NA reaching Cisco?

No. (because of #2)

> Any switch on the path?

It is an L2 circuit that rides a couple of different pieces of gear before it lands at the other side.
> [lazy mode on] I'd also suggest:
>  - debug ipv6 nd on cisco
>  - checking for bugs for IOS and JunOS versions you are using

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