[171098] in North American Network Operators' Group
Re: EIGRP support !Cisco
daemon@ATHENA.MIT.EDU (Laurent Vanbever)
Fri Apr 18 09:30:18 2014
From: Laurent Vanbever <vanbever@CS.Princeton.EDU>
In-Reply-To: <CAAAwwbW16ykHkf8h+=gq81DH_Uj1GYDNkQ_3NdA+yc2JziqYbA@mail.gmail.com>
Date: Fri, 18 Apr 2014 09:04:37 -0400
To: Jimmy Hess <mysidia@gmail.com>, nanog list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hi folks,
A bunch of collaborators and I worked on the problem of IGP =
migration/reconfiguration before. Basically, we augmented Vijay=92s =
methodology to guarantee its correctness. Indeed, when you start =
flipping Administrative Distance (AD) between IGP1 and IGP2, bad stuff =
(i.e., forwarding loops, BGP oscillations) can happen if you=92re not =
careful. Also, what Vijay describes is a migration between two Link =
State (LS) protocols (in this case, OSPF to ISIS). Migrating from EIGRP =
to a LS has to be treated differently since EIGRP is a Distance Vector =
(DV) protocol: when you flip the AD on router X, routing decisions at =
router Y can be impacted (this was not the case in the AOL migration). =
Fortunately, we managed to get that case covered to.
If you=92re interested in knowing more, we covered the LS-to-LS =
migration case in =93Seamless Network-Wide IGP Migrations=94 (see =
http://vanbever.eu/pdfs/vanbever_igpmig_sigcomm_2011.pdf). Our work =
about DV-to/from-LS is not published yet, but I=92d be happy to share it =
privately (just ping me).
Also, something to keep in mind when you start messing with an IGP: =
usually, there is BGP running on top of it=85 And changing the IGP can =
make BGP decisions go crazy (the decision process rely on IGP cost). We =
described this in another work =93When the Cure is Worse than the =
Disease: the Impact of Graceful IGP Operations on BGP=94 =
(http://vanbever.eu/pdfs/vanbever_igp_bgp_infocom_2013.pdf).
Nick, I=92d be happy to chat OOB if you want to know more or go further =
with this migration.
Cheers,
=97 Laurent
On Jan 24, 2014, at 8:04 AM, Jimmy Hess <mysidia@gmail.com> wrote:
> On Fri, Jan 10, 2014 at 9:57 AM, Christopher Morrow =
<morrowc.lists@gmail.com
>> wrote:
>=20
>> On Fri, Jan 10, 2014 at 10:54 AM, Nick Hilliard <nick@foobar.org> =
wrote:
>>> On 08/01/2014 18:14, Christopher Morrow wrote:
>>>> question... there's people that have done this before even :)
>>> https://www.nanog.org/meetings/nanog29/presentations/gill.pdf
>>=20
>> oh yea! that guy! I hear he's done this sort of thing a few times
>> now... probably has practice and tools and stuff :)
>>=20
>=20
> Hey... Tools.... why not... Control+Click... select all the =
routers....
> Right click "Upgrade IGP to ISIS"
>=20
> Go grab a drink... Come back... "Done" click OK. No more Eigrp.
>=20
> I suppose PuTTy / SecureCRT haven't added the feature yet...
> perhaps in a few releases? :)
>=20
>=20
> --=20
> -JH
