IST Ports & MAC Addresses

[rjenk]

We routinely use a tool from Solarwinds called Switch Port Mapper.  It basically pulls the MAC table from a switch and compares it to the ARP cache on your L3 switch (8600) to provide you with a list of each port on the switch, and the MAC, IP address, and DNS/NB name of the connected device.  Real handy for keeping our network documentation up to date.

Today I ran the tool against a pair of 5530's that are part of a full mesh with our 8600's (two core 8600, two 5530's acting as a small distribution core).  What caught my eye was that on each of the 5530's, one of the two ports that are part of the IST and one of the two ports going back to the 8600's have no MAC addresses associated - all of the MACs were on one port of the IST and SMLT.

I figured that it would be somewhat distributed between the pair of links both for the IST between the 5530's and the SMLT back to the 8600's.

The 5530's are operating at L3 with advanced licenses, software 6.0.0.6.  The core 8600's are running 5.0.5.0. 

Any thoughts?

[Michael McNamara]

I can test for you on 5.1.x software and report back... I'm guessing that you are just polling the standard RFC SNMP mibs for the IP ARP table, and not polling the Nortel/Avaya specific rcBridge or other SNMP MIB.

I'll let you know what I see with 5.1.x software on an ERS5530 cluster.

Cheers!

[tbigby]

I'm pretty sure this is usual on the 5xxx series, all MAC addresses show up as being seen on the first port in the trunk only. The switch sees the trunk as a single link so it doesn't matter to it which link the MAC address is seen on.

I just checked under Device Manager on v6.1 on a stack of 5530s, and am seeing this: when looking at Edit - Bridge - Forwarding, all MAC addresses show up on 1/26 and none on 2/23 for example. In fact, it reports the port as '1/26 (Trunk 1)'. But by graphing the two ports and looking at the cumulative traffic, I can see that both ports are being used (sort of equally).

The 470 that we have MLT'd does appear to show the MAC addresses by port number, but our 8600 only shows the trunk name under the port column, eg. 'Uplink to Core'. Must be something that's changed with the newer switches.

[bwilliams2]

I expect this is "normal" behavior.