[c-nsp] changing from ospf to eigrp

Ben Steele ben at internode.com.au
Sat Apr 5 00:04:59 EDT 2008


Actually just to correct myself before anyone else decides to, I think  
ships in the night refers to using a different network protocol aswell  
as a different routing protocol working independently of each other,  
ie ipv6 with OSPF and ipv4 with EIGRP, either way you get my drift :)

On 05/04/2008, at 1:39 PM, Ben Steele wrote:

> What you are doing is known as "ships in the night routing" where you
> run multiple protocols that are unaware of each other, I would go
> ahead and deploy your EIGRP config while keeping your OSPF running and
> as someone else has mentioned the default admin distance for EIGRP is
> 90 which will take precedence over your 110 OSPF, bare in mind if you
> use redistributed routes in EIGRP they will show up as admin distance
> of 170 though.
>
> Either way just go from router to router deploying your EIGRP and then
> when your happy you've done all your devices go and check your route
> tables to see what OSPF routes are still showing up and then determine
> why, and if they are needed, as EIGRP obviously isn't seeing them (at
> least from a non redistributed PoV).
>
> OSPF will pick up your slack while you deploy this in the above
> method, the only real danger I see is if you a) miss a router or b)
> fail to check the route tables for remaining OSPF routes after full
> EIGRP migration before turning OSPF off.
>
> Ben
>
> On 05/04/2008, at 12:30 PM, Whisper wrote:
>
>> So long as the OSPF network remains intact until the EIGRP network
>> is up and
>> running, OSPF should effectively operate as a backup route in the
>> cases
>> where EIGRP has no route, correct?
>>
>> It'd it be like running a floating static route, except your using a
>> dynamic
>> routing protocol, wouldn't it?
>>
>> On Sat, Apr 5, 2008 at 10:52 AM, Jeremy Stretch <stretch at packetlife.net
>>>
>> wrote:
>>
>>>> Can I run both at the same time?
>>>
>>> If you do, you may want to consider tweaking the administrative
>>> distances until EIGRP has been fully implemented across the network.
>>> Remember, by default EIGRP has an AD of 90 (internal) and OSPF of
>>> 110,
>>> so EIGRP-learned routes will be preferred. This has the potential to
>>> cause problems if EIGRP is misconfigured or only partially enabled
>>> during migration.
>>>
>>> stretch
>>> http://www.packetlife.net/
>>>
>>> Dan Letkeman wrote:
>>>> Hello,
>>>>
>>>> I would like to change our layer 3 switches from ospf to eirgrp.   
>>>> Is
>>>> there a way I can accomplish this on a live system without causing
>>>> problems?  Can I run both at the same time?
>>>>
>>>> Thanks,
>>>> Dan.
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