>Could anyone explain how Netview creates networks.
>Does netview look at the IP address and submask and work out
>how many devices will be in the Network.
When it finds out about an interface, it needs to make a network to
put it on if one does not already exist. It uses snmp and other means
to try to find out the network mask and calculates the network address.
If it can't, sometimes it calls it a Class A network and makes one of
those. Via snmp it finds out about other interfaces on the same device,
and makes routers to connect the networks that the interfaces are on. So
networks first, and the levels below them, then routers connecting networks.
>A while back I posted a question regarding netowrks being discovered as
>routers. Netview discovers the correct routers but does not create the
>network and join them up.
Is this a frame relay connection? I have found that Cisco routers need to be
at IOS level 11.2 for Netview to draw them correctly. Before that, the Cisco
agent on the routers did not populate the MIB tables required for Netview do
draw the connection between the routers. Otherwise, take that DUP message
to heart. Netview doesn't draw objects for duplicate address, (well, depending
on your maintenance level) which are illegal. Correct any dups and see if it
clears up.
>I have Segment 0 , 1 , 2 why are they being created ?
I'm not sure what you mean by Segment. If you mean networks, on the IP
Internet submap (top map) named 0, 1, and 2, you get these sometimes during
the course of discovery. Usually it means that Netview found out about an
interface with a bad mask or bad address on it, and made that Network to
hold it. If you mean Segment, there is always one or more segments in a
Network submap. Different devices whose addresses put them in the same
network may be of different protocols (eg ethernet, tokenring, frame, etc.).
Netview will make one segment for each type of interface it finds and group
the nodes in the Segment submaps. Non-snmp things go in the 'other' category,
which will be a bus segment, if they are found first, or may just get
thrown in with the tokenrings if tokenrings are found first. Besides segments,
the network submap will also contain another view of routers, hubs, and
devices like that which are defined in the oid_to_type file to be something
important. The Segment-level submap will contain everything, including the
non-snmp stuff with that network address.
>One of my server boxes is in the database , when issuing an ovtopdump
>it appears however when I do a ovobjprint -s it lists the object but does
>not mention a map. I have dumped all my maps and am unable to find this
>object. How do I delete out of the database? This same server appeared
>on this segment0 as I previously mentioned so I deleted it but it just came
>back to the same segment so I deleted the segment.
>Now I can't find the object.
If you have more than one map, and have deleted something, you have to delete
it from all maps (maps as in 'default' is a map) before you can rediscover it.
If you are having trouble discovering things, I strongly recommend that you
get down to one map until your discovery is complete. This makes things go
a lot better. And do the database administration steps to sync up the different
databases. I use:
ovmapcount -a
ovstop netmon
ovtopofix -a
ovstop ovtopmd
ovtopofix -Cv
ovstart
See the man pages for more info on these commands.
I would suspect that you have a partially discovered object. It is also possible
that the device has multiple interfaces but does not hav ipforwarding enabled,
or does not have snmp configured correctly.
>When Netview tries to discovers an object what does it do. ie.
>a ping demandpoll ???.
It does something like what demandpoll does.
Hope this helps.
Cordially,
Leslie Clark
IBM Global Services - Network & Systems Management - Detroit
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