When you have MLMs and tell NetView to distribute polling to MLMs it will
distribute the polling of interfaces that are in the MLM's subnet. As
part of this mechinism it creates a SmartSet of all those interfaces. If
you go into the definition of that SmartSet and change it so that
additional interfaces are in it, then NetView will distribute polling of
those additional interfaces as well.
There are limitations:
While all this is good, be careful with this. It takes time for netmon to
distribute the interface information to MLMs. While it is doing that work
netmon is not polling the rest of the network. For example in a very
large network you try and distribute polling of 20,000 interfaces to a
couple of MLMs. It will take 10 or more minutes for netmon to distribute
that polling. Also, if something changes that is small, like a new
interface is discovered and needs to be distributed, netmon will have to
redistribute all the interfaces to that particular MLM, not just the delta.
When MLM starts polling the interfaces, he does not know what NetView
knows, so the MLM sends an UP or DOWN trap for every interface that he is
starting to poll to make sure NetView has the right status. In this
example, this would be 20,000 status traps hitting NetView.
There are some great uses of MLMS:
For handling small remote networks behind a slow link, MLM is great. As
a trap receiver with filters and thresholds, MLM is great.
Stephen Hochstetler firstname.lastname@example.org
International Technical Support Organization - Austin
Office - 512-436-8564 FAX - 512-436-9326
ITSO redbooks at http://www.redbooks.ibm.com