IPv6 routing protocols

Nick Hilliard nick at foobar.org
Fri Jun 10 12:26:09 UTC 2011

On 10/06/2011 11:37, Iljitsch van Beijnum wrote:
> So it depends a little, but I still don't see any implementation leeway in RFC 2545:

On all competently constructed interior networks, ibgp will use loopbacks 
as the session endpoints.  This means that the loopback address will be 
carried as the next-hop in the UPDATE messages rather than the link local 
address.  Ok, you can do physical interface to physical interface on ibgp 
if you want, and if you do, good luck with that idea.

For those bgp sessions which use directly connected subnets (e.g. most ebgp 
and badly configured interior networks), this is implementation dependent. 
  Some stacks by default provide both the link-local and the global 
address; others provide just the global address;  others still will provide 
link-local depending on interface configuration (e.g. the per-interface 
"ipv6 enable" command on IOS).

Once the router has learned the next-hop, it may or may not choose to 
display it differently when you're displaying ipv6 forwarding information. 
Some router stacks implement implicit next-hop resolution for their own RIB 
to forwarding table; others don't.  Some will display this information and 
others don't.

So really, it depends.


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