RE: Migration EIGRP-OSPF [7:5724]

2001-05-29 Thread David Wolsefer

Yes,

We laid in OSPF over EIGRP since the administrative distance of EIGRP is 90
and OSPF is 110. We were then able to check the OSPF databases on each
router to make sure that all routes are advertised correctly. The final step
was to remove eigrp. This results in some downtime, but it was easier to
schedule a block of downtime and cut over.


Regards,

David Wolsefer, CCIE #5858

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Dyson Kuben
Sent: Thursday, May 24, 2001 5:59 AM
To: [EMAIL PROTECTED]
Subject: Migration EIGRP-OSPF [7:5724]


anyone out there ever migrated a large-scale network from EIGRP to OSPF?
Would you be able to share your experiences?

Thanks,

Dyson
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RE: Migration EIGRP-OSPF [7:5724]

2001-05-31 Thread R. Benjamin Kessler

You also need to make sure that you have good address summarization if you
want it to be successful.  I've seen more than my fair share of networks
that ran EIGRP, didn't have proper summarization and/or had a lot of
redundancy.  Because, out of the box EIGRP doesn't "require" you to build
networks with summarization, etc. like OSPF.  A few years back (before Cisco
started publishing more details about scaling EIGRP) I saw several networks
that were experiencing stability problems when running EIGRP and the thought
was that OSPF would fix their problems.  Most of these companies balked at
the thought of re-addressing the network to properly support OSPF and stayed
with EIGRP - using a lot of distribute-lists, etc. (although the same
reasons that OSPF "requires" summarization would be of great benefit in an
EIGRP network).

I've found that binary math is not commonly held skill-set.

What is the reason for going to OSPF in this instance, stability problems
with EIGRP or multi-vendor support?

In my experience people seem to view EIGRP as "easier" than OSPF - while
probably true in really small networks, networks these days just seem to be
getting bigger and the same planning required for a successful OSPF
implementation is required for EIGRP.  I haven't seen too many companies
with all-Cisco routers and a healthy EIGRP network looking to change
things - thus the question above.

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
David Wolsefer
Sent: Tuesday, May 29, 2001 7:00 PM
To: [EMAIL PROTECTED]
Subject: RE: Migration EIGRP-OSPF [7:5724]


Yes,

We laid in OSPF over EIGRP since the administrative distance of EIGRP is 90
and OSPF is 110. We were then able to check the OSPF databases on each
router to make sure that all routes are advertised correctly. The final step
was to remove eigrp. This results in some downtime, but it was easier to
schedule a block of downtime and cut over.


Regards,

David Wolsefer, CCIE #5858

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Dyson Kuben
Sent: Thursday, May 24, 2001 5:59 AM
To: [EMAIL PROTECTED]
Subject: Migration EIGRP-OSPF [7:5724]


anyone out there ever migrated a large-scale network from EIGRP to OSPF?
Would you be able to share your experiences?

Thanks,

Dyson
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http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
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RE: Migration EIGRP-OSPF [7:5724]

2001-05-31 Thread Carroll Kong

At 08:27 AM 5/31/01 -0400, R. Benjamin Kessler wrote:

>What is the reason for going to OSPF in this instance, stability problems
>with EIGRP or multi-vendor support?
>
>In my experience people seem to view EIGRP as "easier" than OSPF - while
>probably true in really small networks, networks these days just seem to be
>getting bigger and the same planning required for a successful OSPF
>implementation is required for EIGRP.  I haven't seen too many companies
>with all-Cisco routers and a healthy EIGRP network looking to change
>things - thus the question above.

Well, a few points I would bring up is.

Stuck in Active problem of EIGRP.  As the updates are being done, the 
routers will stay in "active" mode (cannot receive new updates I 
believe).  If the EIGRP network is big, it must wait for the very last 
router in the periphery to respond back.  This could cause issues with 
convergence time.  You may have to modify the timers to increase the hold 
time (which might cause bad convergence) since genuine requests might take 
so long that they will get "zonked" out and the the router will delete it's 
entry.  This only happens in huge "AS" (in the EIGRP sense of an area of 
sorts).  So, if the idea of using OSPF and breaking into "areas" is bad, 
you technically get the same issue with EIGRP, except in the form of ASes.

Also, you are running a proprietary protocol now.  Although it seems to 
work fine now.  If say, they feel another vendor's product is superior in a 
particular aspect of their network, they might be hard pressed or you will 
need to do some redistribution/distribution lists which is probably going 
to be difficult as well.

I suppose all in all it is still "easier" to use EIGRP.  I agree 
wholeheartedly with your statements.  The cost of going to OSPF might seem 
higher if they are really not that good with it.  In that way it somewhat 
validates them sticking to EIGRP.



-Carroll Kong




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RE: Migration EIGRP-OSPF [7:5724]

2001-06-01 Thread R. Benjamin Kessler
an issue because Layer 3 wouldn't have allowed it.

Given an all-Cisco network I would recommend EIGRP over OSPF any day.  It
has faster convergence and more flexibility than OSPF - there have to be
some benefits to a proprietary protocol, right, otherwise no one would use
it.

I can't stress more that you have to have a solid network design to start
and you have to limit the query scope of DUAL (effectively breaking the
network into "areas") in order to have a stable, scalable network.  If you
don't do these things, at some point it will break and you'll be looking to
migrate to OSPF.

Sorry for the long response...

I hope this helps,

Ben

-Original Message-
From: Carroll Kong [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 31, 2001 10:32 AM
To: R. Benjamin Kessler
Cc: [EMAIL PROTECTED]
Subject: RE: Migration EIGRP-OSPF [7:5724]


At 08:27 AM 5/31/01 -0400, R. Benjamin Kessler wrote:

>What is the reason for going to OSPF in this instance, stability problems
>with EIGRP or multi-vendor support?
>
>In my experience people seem to view EIGRP as "easier" than OSPF - while
>probably true in really small networks, networks these days just seem to be
>getting bigger and the same planning required for a successful OSPF
>implementation is required for EIGRP.  I haven't seen too many companies
>with all-Cisco routers and a healthy EIGRP network looking to change
>things - thus the question above.

Well, a few points I would bring up is.

Stuck in Active problem of EIGRP.  As the updates are being done, the
routers will stay in "active" mode (cannot receive new updates I
believe).  If the EIGRP network is big, it must wait for the very last
router in the periphery to respond back.  This could cause issues with
convergence time.  You may have to modify the timers to increase the hold
time (which might cause bad convergence) since genuine requests might take
so long that they will get "zonked" out and the the router will delete it's
entry.  This only happens in huge "AS" (in the EIGRP sense of an area of
sorts).  So, if the idea of using OSPF and breaking into "areas" is bad,
you technically get the same issue with EIGRP, except in the form of ASes.

Also, you are running a proprietary protocol now.  Although it seems to
work fine now.  If say, they feel another vendor's product is superior in a
particular aspect of their network, they might be hard pressed or you will
need to do some redistribution/distribution lists which is probably going
to be difficult as well.

I suppose all in all it is still "easier" to use EIGRP.  I agree
wholeheartedly with your statements.  The cost of going to OSPF might seem
higher if they are really not that good with it.  In that way it somewhat
validates them sticking to EIGRP.



-Carroll Kong




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