OSPF vs IS-IS

jim deleskie deleskie at gmail.com
Fri Aug 12 06:57:46 CDT 2011


If a network is big enough big / complex enough that you really need
to worry about performance of mesh groups or tweaking areas then its
big enough that having a noc eng page you out at 2am when there is an
issue doesn't really scale.  I'm all for ISIS, if I was to build a
network from scratch I'd likely default to it.  I'm just say, new
features or performance aside the knowledge of your team under you
will have much more impact on how your network runs then probably any
other factor.  I've seen this time and time again when 'new tech' has
been introduced into networks, from vendors to protocols.  Most every
time with engineers saying we have smart people they will learn it /
adjust.  Almost every case of that turned into 6 mts of crap for both
ops and eng while the ops guys became clueful in the new tech, but as
a friend frequently says Your network, your choice.

-jim

On Thu, Aug 11, 2011 at 7:12 PM, Jeffrey S. Young <young at jsyoung.net> wrote:
>
>
> On 12/08/2011, at 12:08 AM, CJ <cjinfantino at gmail.com> wrote:
>
>> Awesome, I was thinking the same thing. Most experience is OSPF so it only
>> makes sense.
>>
>> That is a good tip about OSPFv3 too. I will have to look more deeply into
>> OSPFv3.
>>
>> Thanks,
>>
>> -CJ
>>
>> On Thu, Aug 11, 2011 at 9:34 AM, jim deleskie <deleskie at gmail.com> 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.
>>>
>>> -jim
>>>
>>> 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
>
> This topic is a 'once a month' on NANOG, I'm sure we could check
> the archives for some point-in-time research but  I'm curious to learn
> if anyone maintains statistics?
>
> It would be interesting to see statistics on how many service providers run
> either protocol.  IS-IS has, for some years, been the de facto choice for SP's
> and as a result the vendor and standardisation community 'used to' develop
> SP features more often for IS-IS.  IS-IS was, therefore, more 'mature' than OSPF
> for SP's.  I wonder if this is still the case?
>
> For me, designing an IGP with IS-IS is much easier than it is with OSPF.
> Mesh groups are far easier to plan (more straightforward) easier to change
> than OSPF areas.  As for junior noc staff touching much of anything to do
> with an ISP's IGP at 2am, wake me up instead.
>
> jy
>>>>
>




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