OSPF vs IS-IS

James Jones james at freedomnet.co.nz
Fri Aug 12 12:40:52 UTC 2011


I would not say ISIS is the prefered protocol. Most service providers I have worked with use OSPF. Most networks outside of the US use it from what I have seen and the larger SPs in the US do too. There must be a reason for that.


Sent from my iPhone

On Aug 12, 2011, at 8:23 AM, CJ <cjinfantino at gmail.com> wrote:

> You guys are making a lot of good points.
> 
> I will check into the Doyle book to formulate an opinion. So, I am
> completely new to the SP environment and OSPF is what I have learned because
> I have ever only had experience in the enterprise.
> 
> It seems that from this discussion, IS-IS is still a real, very viable
> option. So, IS-IS being preferred...realistically, what is the learning
> curve?
> 
> 
> CJ
> 
> On Fri, Aug 12, 2011 at 7:57 AM, jim deleskie <deleskie at gmail.com> wrote:
> 
>> 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
>>>>>> 
>>> 
>> 
> 
> 
> 
> -- 
> CJ
> 
> http://convergingontheedge.com <http://www.convergingontheedge.com>




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