[c-nsp] IPv6, neighbor detection, BGP and my nerves...

[Aftab Siddiqui]

hello elmar,

actually this is normal because ALL the routes you are receving from your
ebgp neighbor will be having the FE80 as next hop of out going (or you can
say incoming) interface i.e. fa1/1 in your case. Why the router doesn't see
the FE80 address when it is of the outgoing interface of the same router?

or I have totally missed your point here? because this is working perfectly
fine for me but ofcourse with a tunnel broker.

Regards,

Aftab A. Siddiqui


On Thu, Mar 4, 2010 at 6:57 PM, Elmar K. Bins <elmi at 4ever.de> wrote:

> Hello everybody,
>
> here's the setup:
>
> Router model is 7301+PA-2FE-TX with IOS 12.3(14)T3. For those
> who shout "upgrade!" already - same problem with 12.4s.
>
> Router is connected to HKIX via FastEthernet1/1.
>
> No problems whatsoever in IPv4, but here's what I have in IPv6:
>
>  1. IPv6 BGP saves routes with a prefix source of <official
>     IPv6 address>, but stores the next hop out of FE80::/8.
>
> [ipv6 bgp]
> BGP routing table entry for 2001:4F8::/32, version 42465
> ...
>  6939 1280
>    2001:7FA:0:1::CA28:A19E (FE80::212:F2FF:FE9C:2150) from
> 2001:7FA:0:1::CA28:A19E (216.218.252.180)
>      Origin IGP, localpref 100, valid, external, best
>
> [ipv6 route]
> B   2001:4F8::/32 [20/0]
>     via FE80::212:F2FF:FE9C:2150, FastEthernet1/1
>
>
>  2. The trouble is that the router does not "see" some of the
>     FE80::/8 addresses most of the time, meaning that IPv6 nd
>     does not resolve (router gets no answer) and leaves "INCMP"
>     entries in the neighbor table.
>
>     At other times (quite rarely), the FE80:: address is reachable
>     and IPv6 ND resolves.
>
>     The official IP address of the partner is always "visible".
>
> [ipv6 nei]
>
> 2001:7FA:0:1::CA28:A19E                     0 0012.f29c.2150  REACH Fa1/1
> FE80::212:F2FF:FE9C:2150                    0 -               INCMP Fa1/1
>
>
> Clearing the ipv6 neighbor table does not help...
>
> Can anyone help me with these following questions:
>
>  Towards 1. above - can I keep the FE80 addresses out of the equation
>  entirely and have BGP save the neighbor address as the next hop?
>
>  Towards 2. above - has anyone seen same behaviour and/or have a
>  - workaround
>  - lead to a bug id?
>
>
> Any help is much appreciated...
>
> Yours,
>        Elmar.
>
>
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