OSPF vs IS-IS

Thu Aug 11 14:04:09 UTC 2011

On Thu, 11 Aug 2011, jim deleskie wrote:

> Having run both on some good sized networks, I can tell you to run
> what your ops folks know best.  We can debate all day the technical
> merits of one v another, but end of day, it always comes down to your
> most jr ops eng having to make a change at 2 am, you need to design
> for this case, if your using OSPF today and they know OSPF I'd say
> stick with it to reduce the chance of things blowing up at 2am when
> someone tries to 'fix' something else.

Agreed.  I did an OSPFv3 vs. IS-IS bake-off in my lab several months ago 
as part of an IPv6 rollout, and one of the key deciding factors in going 
with OSPFv3 over IS-IS was that our ops folks are much more familiar with 
OSPFv2.  While there are difference between OSPFv2 and OSPFv3 in how they 
work, the learning curve is a lot less steep than going from OSPFv2 to 
IS-IS.

jms

> On Thu, Aug 11, 2011 at 10:29 AM, William Cooper <wcooper02 at gmail.com> wrote:
>> I'm totally in concurrence with Stephan's point.
>>
>> Couple of things to consider: a) deciding to migrate to either ISIS or
>> OSPFv3 from another protocol is still migrating to a new protocol
>> and b) even in the case of migrating to OSPFv3, there are fairly
>> significant changes in behavior from OSPFv2 to be aware of (most
>> notably
>> authentication, but that's fodder for another conversation).
>>
>> -Tony
>>
>> On Thu, Aug 11, 2011 at 9:06 AM, Stefan Fouant
>> <sfouant at shortestpathfirst.net> wrote:
>>> Well up until not too long ago, to support IPv6 you would run OSPFv3 and for IPv4 you would run OSPFv2, making IS-IS more attractive, but that is no longer the case with support for IPv4 NLRI in OSPFv3.
>>>
>>> The only reason in my opinion to run IS-IS rather than OSPF today is due to the fact that IS-IS is decoupled from IP making it less vulnerable to attacks.
>>>
>>> Stefan Fouant
>>> JNCIE-M, JNCIE-ER, JNCIE-SEC, JNCI
>>> Technical Trainer, Juniper Networks
>>> http://www.shortestpathfirst.net
>>> http://www.twitter.com/sfouant
>>>
>>> Sent from my iPad
>>>
>>> On Aug 11, 2011, at 8:57 AM, CJ <cjinfantino at gmail.com> wrote:
>>>
>>>> Hey all,
>>>> Is there any reason to run IS-IS over OSPF in the SP core? Currently, we
>>>> are running IS-IS but we are redesigning our core and now would be a good
>>>> time to switch. I would like to switch to OSPF, mostly because of
>>>> familiarity with OSPF over IS-IS.
>>>> What does everyone think?
>>>>
>>>> --
>>>> CJ
>>>>
>>>> http://convergingontheedge.com <http://www.convergingontheedge.com>
>>>
>>>
>>
>>
>
>