From: Devender Singh (devender.singh@xxxxxxxxxxxxxx)
Date: Wed May 23 2001 - 09:28:48 GMT-3
I agree, for danger of creating routing loops( which I doubt when we are
talking just ospf). But it can certainly create ineffiicient routing.
I think the best we can do is to be aware of the issue and clear it with the
proctor if the need be.
Best regards
Devender Singh
BE(Hons), CCNP
IP Solution Specialist
-----Original Message-----
From: Ilya Mazhara [mailto:willy@aspect.vyatka.ru]
Sent: Wednesday, 23 May 2001 9:16
To: Devender Singh
Cc: Mohamed Heeba; 'ccielab@groupstudy.com'
Subject: Re: OSPF summary and redistribution
If you plaing this game u can create routing loop on other routers.
With single area ASBR u may ask proctor to create additional area on
additional loopback
and type area range backbone_net/wished_mask_for_stupid_FLSM_RP. It'll
work without 2nd ospf process.
Devender Singh wrote:
> This my understanding:
>
> Normally summary-address used create a summary from type 5 LSA on ASBR
(Say
> rip to ospf ). But what happens when we use it to summarise the other way
> around. When we redistribute ospf into say RIP, by rules it will get
> redistributed into RIP, but if the mask on the outgoing RIP interface
does
> not match routes will not be progated into rip. The mask on the outgoing
> interface does not have anything to do with basic process of
redistribution.
> Now if we redistribute RIP back into ospf without any route-map or
> distribute-lists all this route will be inserted back into ospf but they
> will not bother ospf because internal routes have preference over external
> routes. Now the summary command ( our hack) does its job and pushes it
back
> to RIP with the mask we want also into ospf domain as external. Rest
> everything is normal.
>
> Does this make sense to you.
>
> Best regards
>
> Devender Singh
> BE(Hons), CCNP
> IP Solution Specialist
>
> -----Original Message-----
> From: Mohamed Heeba [mailto:MAHeeba@itqan.co.ae]
> Sent: Saturday, 12 May 2001 9:04
> To: 'ccielab@groupstudy.com'
> Subject: OSPF summary and redistribution
>
> guys ;
> i have reached a conculation about the problem of the OSPF and
summarization
> /redistribution and wanted to share it with you who are interested .
> i have revised Doyles chapter of redistribution ,there is an example of
> redistributing RIP into IS-IS and at the end of this chapter ,(RIP is /24
> and ISIS is /24 and /28 )
> CLEARLY ,he NEVER use the command summary-address to summarize the ISIS
> routes to the RIP and clearly also mentioned that ISIS /28 routes should
be
> summarized to RIP by using STATIC ROUTES !!!!.
> so the point is the summary command should only be used to summarize
> extrenal routes INTO ISIS or OSPF .but our problem is that we were trying
to
> go around this problem to avoid the use of static routes ,while in fact it
> is an easy way to solve this problem.
> going around the problem can may be done by a command like ip
> default-network ,but this will require the major class network to be
> different in both domains.
> well...i guess in the real lab there should be way to avoid using the
> summary address in opposite way and create more problems ....or they may
> allow to use just single static route somewhere :))))))
>
> hope someone can comment on this
> Mohamed
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