Re: [nv-l] CDP and Discovery

2002-08-04 11:11:24
Subject: Re: [nv-l] CDP and Discovery
From: Jim Kellock <jkellock AT nc.rr DOT com>
Date: Sun, 04 Aug 2002 11:11:24 -0400
I would suggest that this is the behavior of switches rather than
NetView.  A switch doesn't necessarily make it's presence known on the
network.  Unlike a router, server, or other active device, it doesn't
advertise a service or participate in a routing scheme, and therefore
never gets into anybody's arp cache for NV to find, and some switches
also won't respond to a broadcast ping, so unless you tell NV explicitly
to look for your switches, it has no reason to suspect they're there. 
Between these two things, you may want to list the individual IP
addresses of these switches permanently in your seedfile, as you have
tested with success as you state below.  Simply listing the range
probably won't work either.  

In some switches, you may find a function called "autodiscovery" which,
when enabled, causes the switches to do a broadcast ping every so often
so they will get into the nearest router's arp cache, but it just adds
traffic and overhead.  Easier to just add the addresses to the seedfile.

The CDP, like the autodiscovery, would, I think, require that the
multicast sent out
gets to a box that NetView is monitoring for arp.

Hope this proves helpful, and sorry, to Ray: I forgot on the first send
of this to
swap the addresses and sent it to his email address.

"Westphal, Raymond" wrote:
> Hello Everyone.
> NetView 7.1.1 or 7.1.2 on AIX 4.3.3 ML10
> I have noticed a problem with discovery on two NetView servers. NetView
> fails to add Cisco switches, for example 2924 or 2950, to the map. The Cisco
> routers on the same network are on the map, are managed and are demand
> polled every 24 hours. If I telnet to the router(s) and enter the command,
> "show cdp neighbor", the switches are listed by their configured hostname
> which may or may not be the DNS name. The demand poll shows NV is querying
> the CDP cache.
> netmon options are:
>         /usr/OV/bin/netmon -P -S -s/usr/OV/conf/netmon.seed -A -u -l -K0 -q
> 32 -Q 32
> My seed file only contains exclusions, HSRP and SNMP status poll entries. In
> other words, I do not have IP network ranges like 10.10.*.* in the seed
> file. If I add the switch IP address to the netmon.seed file and run the
> netmonaction.sh script, the switches are soon added to the map.
> Any ideas?
> Thanks.
> Ray Westphal
> Enterprise Rent-A-Car
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