Duplicate MAC issue in CM / LMS 3.1

Unanswered Question
Aug 10th, 2009


I want to exclude the ports from which i find duplicate mac entries.

see I have two switches (Sw1, sw2) connected via Access port (not trunked). so what i find is, the Users connected to sw1 is also shown as users of sw2 and they are shown in the port used to connect SW1 and SW2.

I have this problem too.
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Joe Clarke Mon, 08/10/2009 - 08:48

You will need to make sure CDP is running on the link between Sw1 and Sw2. This way, Campus will treat that connection as a topology link (i.e. shows up on the topology map). When that happens, end hosts showing up on that port will be ignored.

Rajiv Dasmohapatra Mon, 08/10/2009 - 09:37

i already have it enabled.

by the way what are these... in ut.properties. can i use these to do the same.



Joe Clarke Mon, 08/10/2009 - 10:16

The UT.DuplicateMac properties only come into play when DHCP support is enabled. They are designed to allow or disallow duplicates on a given switch. They will not solve the problem you are seeing switch the switches in question are different.

However, if both switches are showing up on the topology map, and the link between the two also shows up, then end hosts should not be acquired on that link. What type of switches are they?

Rajiv Dasmohapatra Mon, 08/10/2009 - 12:07

My whole architecture runs on DHCP only.

i attached a sample scenario. the hosts of sw1 also shows in dist4507 on the red line port. the red lines are vl20 and is not routable withing the rest of the network. R1 is managed by vendor. and rest of the network is mine to control.

how can i manage this.

Joe Clarke Mon, 08/10/2009 - 12:21

What I said before still stands. Are both SW1 and Dist4507 showing up on the Campus Topology Map as green with proper icons? If so, then UT should not be showing the duplicates provided the link between the two switches is also on the Topology Map.

The way UT works is to poll the CAM/MAC table from each switch. It will then check the port on which each MAC was found. If the port is a trunk (and trunk port acquisition is not allowed on that port), then the MAC will be dropped. If the port is a topology link (i.e. it shows up on the map), then the MAC will be dropped. Else, the MAC will be learned, and added to the UT end host table.

The only way for a link to be a topology link is for CDP to be running across it, and both device end points are fully managed by Campus Manager.


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