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Layer 3 Issues with MSFC / MLS Ageing


We have recently had some issues where MLS seems to stop working. The symptoms came about when a next hop firewall had its hardware swapped (downstream). We cleared CAM tables on the local switch - however we expected the MSFC (and MLS) to deal with the associated MAC change.

When the firewall was changed - there were a number of connectivity issues ... subsequent we found (we think) that the MLS table on the switch was not ageing out and still had the old MAC address in its table.

This was fixed by clearing the ARP cache on the MSFC - which cleared the MLS table.

Could someone confirm that what has happened actually is the case ... then also is there a command to enabl e aging of this table ?

NOTE : This issue lasted more than 24 hours before we found the fix.

New Member

Re: Layer 3 Issues with MSFC / MLS Ageing

Man that's strange. The MLS cache should clear a flow if it's idle for 256seconds by default if memory serves me right. You can try the #set mls agingtime (agingtime 8-2032 seconds) command to set it so that you know it's right but if you would.. please do a show on it first, i'd be interested to see what it's set to now. Hope this help -Horton

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