Re: Segment discovery

2000-06-12 09:33:04
Subject: Re: Segment discovery
From: lclark AT us.ibm DOT com
To: nv-l AT lists.tivoli DOT com
Date: Mon, 12 Jun 2000 09:33:04 -0400
It sounds like you are talking about subnets, as opposed to what Netview
calls segments and creates under subnets, right?  The networks it draws
(or subnets) are based solely on IP address with masks applied. Some
customers do not administer subnet masks on certain types of devices,
depending on whether their routing protocols require them, and are
surprised at the subnet addresses that Netview decides on in those
cases. If you select a device on the map and do 'Monitor... Network
Configuration... Addresses' (the wording may be different on NT) you
will see the addresses and masks of each interface. These are
pulled directly from the device via snmp. They come from the IP
Address table. Funny ones are useful for finding configuration errors
on the devices. If they are wrong, you can either correct the config
on the device and delete and rediscover it, or you can force it to be
loaded where you want it with the loadhost command, a messy
administrative task but sometimes the only solution.

What Netview calls Segments (Segment1, Segment2, etc) under each
subnet are just groupings based on the interface type as returned by
the device via snmp, eg TokenRing, FDDI, Ethernet, Other, etc.

Hope this helps. If not, ask with more words......


Leslie A. Clark
IBM Global Services - Systems Mgmt & Networking
---------------------- Forwarded by Leslie Clark/Southfield/IBM on
06/12/2000 09:24 AM ---------------------------

"Chance, Larry" <lchance AT sfbcic DOT com>@tkg.com on 06/09/2000 10:40:38 AM

Please respond to IBM NetView Discussion <nv-l AT tkg DOT com>

Sent by:  owner-nv-l AT tkg DOT com

To:   "'NetviewListSERVERUsers nv-l AT tkg DOT com'" <nv-l AT tkg DOT com>

Subject:  [NV-L] Segment discovery

How does Netview determine the Network SEGMENTs when it
does an autodiscovery of the routers throughout the network?

I have users at a remote site that question the SEGMENT numbers
on their map, which was assigned by Netview.

It looks to me that Netview reads the route table entries after gathering
the router's interfaces and masks and calculates the SEGMENT number.
I would think those entries come from the 'routing' protocols used and
configured on the router, along with the 'network' number for the 'routing'
protocol, such as IGRP.  More or less, Is it the configuration of the
that causes the SEGMENT number.  Am I even close?


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