IGP protocol

Victor Kuarsingh victor at jvknet.com
Fri Nov 16 13:04:46 UTC 2018


Some good comments on this thread so far.

Having chosen between OSPF and IS-IS more then once over the past 20 years
for various networks and have chosen differently in some cases.  I have a
general preference for IS-IS in very large networks, but OSPF has performed
well for me in larger nertowrks as well.  I would say at this point, they
both can do the same basic job with a few benefits attributable to each of
them.  With OSPFv3 now more mature, I am sure there may have been a few
classic selections of IS-IS that may no longer go that way (+10 years ago,
many with OSPFv2 networks turned on IS-IS since OSPFv3 implementations were
quite new and IPv6 was staring to come online on backbones).

Anyone turning on either IGP today, the major considerations (in my mind
would be).

1. Which protocol do you have the operational staff to support? (Someone
has to fix things when broken, so what talent do you have in ops?)
2. What protocol design capabilities do you have? (Good designers can learn
either protocol, but historical experience can help in some cases)
3. Based on your vendor preference / selection, how well does each fair on
your platform of choice ? (Most major vendors do a good job on both, but
there are considerations)
5. Some people like that IS-IS is not based on IP and operates directly
over Layer-2 (some arguable benefits in security domain - but you can
secure both)
6. You running IPv4 and/or IPv6 on your underlay? (If you are running v4
only and use overlay for v4/v6 - some like the maturity of the OSPFv2
7. Considerations for how you want your areas to run (some key differences
in how L1/L2 areas work in IS-IS along with how boundaries work vs. OSPF
areas and boundaries).
8. Route types.  In some networks, folks want to import routes from other
protocols (sometimes incoming protocols running at edges of networks etc).
If you have that, you may want to consider how you want routes to operate.


Victor K

On Mon, Nov 12, 2018 at 2:45 PM im <nanog at netfront.jp> wrote:

> goodmorning nanog,
> I heard that OSPF is only famous in asia region...
> So that, please could you explain me
>   1. what is your backbone's IGP protocol?
>   2. why you choose it?
> thanks,
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