IPv6 routing protocols
Iljitsch van Beijnum
iljitsch at muada.com
Fri Jun 10 05:37:34 CDT 2011
On 10 jun 2011, at 12:27, Iljitsch van Beijnum wrote:
> RFC 4760:
> An UPDATE message that carries the MP_REACH_NLRI MUST also carry the
> ORIGIN and the AS_PATH attributes (both in EBGP and in IBGP
> exchanges). Moreover, in IBGP exchanges such a message MUST also
> carry the LOCAL_PREF attribute.
Sorry, this is stupid. I should have read beyond "LOCAL".
So it depends a little, but I still don't see any implementation leeway in RFC 2545:
3. Constructing the Next Hop field
A BGP speaker shall advertise to its peer in the Network Address of
Next Hop field the global IPv6 address of the next hop, potentially
followed by the link-local IPv6 address of the next hop.
The value of the Length of Next Hop Network Address field on a
MP_REACH_NLRI attribute shall be set to 16, when only a global
address is present, or 32 if a link-local address is also included in
the Next Hop field.
The link-local address shall be included in the Next Hop field if and
only if the BGP speaker shares a common subnet with the entity
identified by the global IPv6 address carried in the Network Address
of Next Hop field and the peer the route is being advertised to.
In all other cases a BGP speaker shall advertise to its peer in the
Network Address field only the global IPv6 address of the next hop
(the value of the Length of Network Address of Next Hop field shall
be set to 16).
More information about the NANOG