nanog mailing list archives
RE: IGP choice
From: "Jameson, Daniel" <Daniel.Jameson () tdstelecom com>
Date: Fri, 23 Oct 2015 18:56:43 +0000
A lot of carriers use ISIS in the core so they can make use of the' overload bit' with a 'set-overload-bit on-startup wait-for-bgp". Keeps them from black holing Traffic while BGP reconverges., when you have millions of routes to converge it can take forever. It's also a really handy tool when you're troubleshooting or repairing a link, set the OL bit, and traffic gracefully moves, then when you're done it gracefully moves back. You can do the same thing with the Metric, and Cost in OSPF, just not quite as elegant. Largely I think it's preference, ISIS and OSPF tackle most of the same stuff just in different ways. -D -----Original Message----- From: NANOG [mailto:nanog-bounces () nanog org] On Behalf Of Matthew Petach Sent: Friday, October 23, 2015 11:31 AM To: marcel.duregards () yahoo fr Cc: nanog () nanog org Subject: Re: IGP choice On Fri, Oct 23, 2015 at 1:41 AM, marcel.duregards () yahoo fr <marcel.duregards () yahoo fr> wrote:
sorry for that, but the only one I've heard about switching his core IGP is Yahoo. I've no precision, and it's really interest me. I know that there had OSPF in the DC area, and ISIS in the core, and decide to switch the core from ISIS to OSPF.
Wait, what? *checks memory* *checks routers* Nope. Definitely went the other way; OSPF -> IS-IS in the core.
Why spend so much time/risk to switch from ISIS to OSPF, _in the core_ a not so minor impact/task ? So I could guess it's for maintain only one IGP and have standardized config. But why OSPF against ISIS ? What could be the drivers? People skills (more people know OSPF than ISIS) --> operational reason ?
I'm sorry you received the wrong information, the migration was from OSPF to IS-IS, not the other way around. Thanks! Matt
Current thread:
- IGP choice marcel.duregards () yahoo fr (Oct 22)
- Re: IGP choice Niels Bakker (Oct 22)
- Re: IGP choice marcel.duregards () yahoo fr (Oct 23)
- Re: IGP choice Matthew Petach (Oct 23)
- RE: IGP choice Jameson, Daniel (Oct 23)
- Re: IGP choice Pablo Lucena (Oct 23)
- Re: IGP choice Mikael Abrahamsson (Oct 23)
- Re: IGP choice marcel.duregards () yahoo fr (Oct 23)
- Re: IGP choice marcel.duregards () yahoo fr (Oct 26)
- Re: IGP choice Niels Bakker (Oct 22)
- RE: IGP choice Damien Burke (Oct 22)
- RE: IGP choice Steve Mikulasik (Oct 22)
- Re: IGP choice Randy via NANOG (Oct 22)
- Re: IGP choice Dave Bell (Oct 22)
- Re: IGP choice Mark Tinka (Oct 22)
- Re: IGP choice sthaug (Oct 22)