[c-nsp] General Question to OSPF

[Oliver Boehmer (oboehmer)]

Hi,

this is expected, OSPF will only form adjacencies via the primary
address on the interface.

	oli

A. Rahman Isnaini R Sutan <> wrote on Sunday, March 19, 2006 4:15 PM:

> Oliver,
> 
> 
> It might be a bit out of topic.
> The OSPF session will not up if the network set on IP secondary on the
> interface.
> We should replace the primary with on of IP in the network to bring
> the OSPF to work out.
> 
> Not just like BGP/IBGP, as long as you can reach though it's set as
> secondary IP on interface so it should be Up.
> 
> Any expalantion from Cisco regarding this ?
> 
> Rgs,
> a. Rahman Isnaini r. Sutan
> 
> ----- Original Message -----
> From: "Oliver Boehmer (oboehmer)" <oboehmer at cisco.com>
> To: <acm at netuse.de>; <cisco-nsp at puck.nether.net>
> Sent: Sunday, March 19, 2006 4:37 PM
> Subject: Re: [c-nsp] General Question to OSPF
> 
> 
>> Ahmad Cheikh-Moussa <> wrote on Saturday, March 18, 2006 1:17 PM:
>> 
>>> Hi!
>>> 
>>> I made some thoughts about an ospf design.
>>> I would like to know, what other people think about it.
>>> 
>>> Here it is.
>>> I have 4 cisco routers. All of them are connected together
>>> in a ring topology. All connections have the
>>> same bandwith/delay and so on.
>>> The routers are connetcted via transfer networks
>>> and all of them are in area 0.
>>> Two of the four routers have uplinks to two BGP
>>> routers. Both BGP routers are the default gateways
>>> for the other 4 routers. The uplinks are
>>> separated in two transfer networks in area 0.
>>> 
>>> Is there something I should keep in mind, when I try
>>> such a configuration  ?
>>> What happens, when OSPF has several equal routes ?
>>> routing loops ??
>> 
>> Just enable OSPF as you described, and it will work. If you have
>> equal-cost paths, OSPF will install multiple paths into the RIB and
>> the router will load-share. There is no risk for loops if you let
>> OSPF do all the routing. You do need to take a look at your iBGP
>> topology, though. If you don't run BGP on all the transit routers,
>> you could run into loops. But I miss more detailed info about the
>> BGP topology in order to evaluate this. 
>> 
>> oli
>> 
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> 
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