[162967] in North American Network Operators' Group
Re: ISIS and OSPF together
daemon@ATHENA.MIT.EDU (Peter Ehiwe)
Sun May 12 04:51:25 2013
In-Reply-To: <CAPLq3UN6KcDLxA9uq+XW9PLt04YGwaHHe3N-6i136upbCEc5eQ@mail.gmail.com>
From: Peter Ehiwe <peterehiwe@gmail.com>
Date: Sun, 12 May 2013 09:51:07 +0100
To: Glen Kent <glen.kent@gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Ospf offered as Pe-ce protocol to L3 mpls vpn customers and Isis as IGP for=
MPLS Core.
Sent from my iPhone
On May 12, 2013, at 9:41 AM, Glen Kent <glen.kent@gmail.com> wrote:
> Hi,
>=20
> I would like to understand the scenarios wherein the service
> provider/network admin might run both ISIS and OSPF together inside their
> network. Is this something that really happens out there?
>=20
> One scenario that i can think of when somebody might run the 2 protocols
> ISIS and OSPF together for a brief period is when the admin is migrating
> from one IGP to the other. This, i understand never happens in steady
> state. The only time this can happen is if an AS gets merged into another
> AS (due to mergers and acquisitions) and the two ASes happen to run ISIS
> and OSPF respectively. In such instances, there is a brief period when two=
> protocols might run together before one gets turned off and there is only
> one left.
>=20
> The other instance would be when say OSPF is used to manage the OOB networ=
k
> and the ISIS is used for network reachability.
>=20
> Is there any other scenario?
>=20
> Glen
