RE: Summarization [7:31766]

2002-01-14 Thread David j

Hello Ben, thanks for your detailed answer. 
I'm afraid I have no idea what happened but I'm think that it wasn't a
problem with CPU unless summarization is a very intensive cpu process(I
don't know if it is).
We have a hub-and-spoke topology. Four 7500 (2 7513 and 2 7507) for backbone
(ATM)and over 230 sites (2500 an 2600 mainly), and we have implemented
redundancy using dialers and ISDN connections (and yes, we have conected
each router to two different hub routers). In one of the 7513 we have over
100 dialers and 90 serial WANs connections, I have tried the summarization
again with only two routers and by now, I haven't experimented any problem.
 As you can guess, our network is growing more and more and I'm worried
about routing tables with a lot of entries (we're using network 172.x.x.x
for serial interfaces and 10.x.x.x for ethernet interfaces)
I tried to summarize on networks 10.x.x.x and 172.x.x.x using the following
commands
ip summary-address eigrp 1 10.0.0.0 255.0.0.0
ip summary-address eigrp 1 172.0.0.0 255.0.0.0
Today, I have talked with my boss and we've decided to try the summarization
again but we're going to use the 0.0.0.0 network instead the other two (I'll
try to check my RSP in-depth this time)
Anyway, we're not experts in Cisco so I thought that we could reduce routing
tables using summary address and make easier the administration and
troubleshooting (perhaps it isn't a good idea). Unfortunatly, we work in a
helth-care enviroment, and we have to make sure before doing anything in
backbone routers.
I hope you read this post, I live in Europe and every time I have to reply a
post I have hundreds before me. Anyway, I'll keep you and this wonderful
group informed.

David




Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=31888t=31766
--
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]



RE: Summarization [7:31766]

2002-01-13 Thread R. Benjamin Kessler

I've done it with about 100 interfaces on 7513's and didn't see this
problem.  It may be a limitation of the code on the box, memory (as you
indicated), or something else.  Have you been able to rule-out as many
something elses as possible?

What does the network topology look like?  Do you have redundancy in place -
e.g. spoke routers connected to two different hub routers?  Are you getting
a lot of SIAs?  Routes flapping, etc.?  How's the CPU on your RSP's looking?
Free memory?  Buffer misses?

There's a common view that EIGRP works fine and can scale infinitely big
without going through all of the steps that you'd have to go through for a
large-scale OSPF installation.
Obviously, this thought is very wrong.

I'm guessing that you need to do manual summarization on 200 interfaces per
box is because you don't have clearly-defined summarization points in the
network - that's the situation I was in when I had to do it on ~100
interfaces.  For good or ill, EIGRP will work with a bad network design (I'm
speaking from an ideal perspective - please don't be offended, we all have
to things at one time or another that are considered bad) up until a
point.  Beyond that point, it gets really ugly - quickly.

In the network I was working on we had 140 sites connected without problems.
We started adding more offices and by the time we hit 170 the network was
totally unstable.  After several weeks of P1/CAP cases we met with the guys
who write the code and found out what we were doing wrong - they have since
published several CiscoPress books on EIGRP; none existed four years ago :)

You can band-aid a broken network by using a lot of the EIGRP features
(manual summarization, distribute-lists, etc.).  In my case that's exactly
what we did, unfortunately, I was not given the opportunity to correct the
mistakes that required the band-aids.  I have since moved on to new
challenges but that network is still in the same state - four years later.

Anyhow, if you can offer more specifics, I'm sure those of us on the list
would be happy to comment and offer suggestions.  I think that if we can
solve the reason you need to manually summarize on 200 interfaces you'll be
better off down the road.

Ben

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Sunday, January 13, 2002 5:02 AM
To: [EMAIL PROTECTED]
Subject: Summarization [7:31766]


Hello folks,
I'm working in a EIGRP enviroment, and I have some questions for you:

Has anyone tried to do a manual route sumarization per interface with more
or less 200 interfaces in a 7500?
I've tried but I'm having a few problems, the summary routes aren't
advertised sufficiently fast to the routers in branch offices.
The summary routes are sometimes marked as possibly down in the routers of
branch offices, sometimes are up and sometimes are down.

Do you know any relationship between memory or cpu (or whatever) of the 7500
and number of interfaces in which you can perform manual summarization?

David




Message Posted at:
http://www.groupstudy.com/form/read.php?f=7i=31787t=31766
--
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]