Subject: [Idr] Status of the AddPath Capability

From: Uli Bornhauser <[email-masked]>
Date: Mon, 03 Dec 2007 08:44:12 +0100

Hello Everybody,

my name is Uli Bornhauser, and I am a PhD. Student at the University of
Bonn, Germany. I’m working in the area of Inter Domain Routing, trying
to develop new BGP routing architectures. This area of research is
motivated by routing anomalies as temporal and consistent divergence,
for example, that come along with iBGP scaling techniques such as iBGP
Route Reflection.

Obviously, there are various approaches discussed in literature to avoid
these and other routing anomalies using Route Reflection. As some of you
certainly know, some interesting approaches try to avoid these anomalies
by advertising additional path information via a BGP session between two
BGP peers (AddPath capability). Extensions to advertise several paths
for a single destination through the same BGP sessions are discussed by
Daniel Walton, Alvaro Retana, and Enke Chen [1] as well as Manav Bhatia,
Joel M. Halpern, and Paul Jakma [2], for example.

In the last months, I have considered some new approaches which can
avoid various routing anomalies in general. However, to make these
approaches usable in practice its seems to be necessary to exchange more
path information in the AS than specified in BGPv4, as described in the
Internet Drafts mentioned above.

>From my point of view, an interesting question is what status these
documents have? Is anyone working in this area and are there efforts at
the current point in time to include these extension in BGP? The last
information about this topic I found is the IETF‐65 IDR minutes [3].
What happen after that? Are there any new developments in this area in 2007?

I am grateful for all comments and suggestions.

Regards

Uli Bornhauser

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Uli Bornhauser                University of Bonn
                              Institute of Computer Science IV
Email: [email-masked]      Roemerstr. 164
Phone: +49 (228) 73 - 4550    D - 53117 Bonn
Fax:   +49 (228) 73 - 4571    Germany

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From: Uli Bornhauser <[email-masked]>
Date: Fri, 07 Dec 2007 19:27:17 +0100

Hi Mantav, hi all,

thank you for the information. They help me to get a better overview
about the current status of the addpath capability. Mantav, while you
might be right that there was a want of interest regarding addpath in
the past, I think this does not match the current situation. For my
studies I cooperate with Deutsche Telekom AG, who is also very
interested in a support of addpath in their routers. So, interest at
this point seems to be abundant.

Well, you ask what I have in mind: I made some analysis regarding both
full-mesh iBGP and iBGP Route Reflection to study new approaches
avoiding routing anomalies. One approach requires the advertisement of
additional routing information as described by the Addpath-capability.

Greetings

Uli

Bhatia, Manav (Manav) schrieb:
>
> The discussion has fallen into an abeyance because of lack of provider interest for such a capability, i.e. to advertise multiple paths in BGP. And the two drafts thus stand in limbo.
>
> However this should not discourage you from your work. What exactly do you have in your mind?
>
> Cheers,
> Manav
>