Re: Unnumbered and tunnel interfaces in OSPFv3

[Acee Lindem <acee at REDBACK.COM>]

Hi Nic,

----- Original Message -----
From: "Nic Neate" <Nic.Neate at DATACONNECTION.COM>
To: <OSPF at PEACH.EASE.LSOFT.COM>
Sent: Monday, September 06, 2004 10:20 AM
Subject: Re: Unnumbered and tunnel interfaces in OSPFv3


> Hi Acee,
>
> Thanks for your response.  I agree that the Link-LSA doesn't seem to have a
> purpose on unnumbered links, and perhaps an option not to use the Link-LSA
> on any P2P links would also be appropriate.
>
> To tie things down, I think we agree that OSPFv3 should run over unnumbered
> interfaces as follows.  Please let me know if there is anything missing or
> incorrect.
>
> - For OSPFv3 purposes, an unnumbered interface is defined as an interface
> with no link-local address (but possibly with site-local or global
> addresses).

It funny but I would have interpreted it to be just the opposite - an interface
with a link-local address of one sort or another and no site-local or global
addresses.

> - Any address on the corresponding node is used for the source/destination
> address in protocol packets sent over unnumbered interfaces (as in OSPFv2).

I don't agree here since I think there still should be a link-local address.

> - Unnumbered interfaces are identified in the protocol (for example, in
> Router-LSAs) by their Interface ID and Router ID (as with numbered
> interfaces).

Agreed.

> - The Link-LSA is not sent over unnumbered interfaces.  Any site-local or
> global addresses configured are advertised in the router's
> Intra-area-prefix-LSA.

I don't think the Link-LSA is required on P2P links - see below.

> Do you think there would be scope/demand for a short draft to standardize
> this?  I would be happy to contribute if so.

In thinking about this more, I think an "unnumbered" link in IPv6 is simply
any interface that has a link-local address but no global addresses (note
that site-local addresses have been deprecated). Hence, this is already
handled by RFC 2740. We may want to have more discussion of allowing
link-LSAs to be omitted on P2P links.



> Thanks,
>
> Nic
>
>
> -----Original Message-----
> From: Acee Lindem [mailto:acee at REDBACK.COM]
> Sent: Thursday, September 02, 2004 10:26 PM
> To: OSPF at PEACH.EASE.LSOFT.COM
> Subject: Re: Unnumbered and tunnel interfaces in OSPFv3
>
>
> Hi Nic,
>
> ----- Original Message -----
> From: "Nic Neate" <Nic.Neate at DATACONNECTION.COM>
> To: <OSPF at PEACH.EASE.LSOFT.COM>
> Sent: Thursday, September 02, 2004 10:55 AM
> Subject: Unnumbered and tunnel interfaces in OSPFv3
>
>
> > Hi all,
> >
> > I have a few OSPFv3 questions I was hoping someone could help me with.
> >
> > 1.  Is there any concept of an unnumbered interface in OSPFv3?  (As far as
> I
> > can see from RFC 2740, there isn't.)
>
> Since OSPFv3 runs on a link rather than a subnet, there should be fewer
> considerations.
>
> > 2.  If yes, how do they work?  I would guess most principles from OSPFv2
> can
> > be carried over, but what about usage of the Link-LSA?
>
> It seems that it could be suppressed for unnumbered LSAs. In fact, it has
> crossed
> my mind that they could be suppressed for all OSPFv3 P2P links. At least in
> our
> implementation, we don't need to discover the link local address and any
> prefixes
> associated with the link are advertised in one of the router
> intra-area-prefix LSAs.
>
>
> > 3.  If not, are there any guidelines on how, for example, RSVP tunnel
> > interfaces should be handled?
>
> I would think this would be transparent to OSPFv3.
>
> > Thanks in advance,
> >
> > Nic