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jakirbasha69
Beginner

Port Mach Hash Failed

Hi,
I have a cisco sg350x 24 port with 10gig uplinks running as as small scale isp distribution switch
 my network scenario is i have 3 different isp routers connected to 1 gig ports
remaining were used as downlinks. I am getting this error "%2SWMACTBL-N-PORTMACHASHFAILED: Port gi1/0/24 ,MAC 7c:a9:6b:73:e3:c2 : Cannot be added to the FDB (Hash Table Collision)" frequently. every now and then with different mac address. switch has approx 330 active vlans.  i couln't find any hardware loop or soft loop in my network.
any help would be much appreciated.

1 ACCEPTED SOLUTION

Accepted Solutions

Hello,

the number of drop events when compared to total packets received leads to a low drop probability that should not be an issue

 

Hope to help

Giuseppe

 

View solution in original post

3 REPLIES 3
Giuseppe Larosa
Hall of Fame Master

Hello @jakirbasasha69,

 

verify if the same MAC address is learned on another VLAN on another port at the same time.

 

We have seen a similar issue on recent IOS switch C3560 with IOS XE 16.9.5 in a customer network.

We have found that this case same MAC address learned on different VLANs on different ports caused log messages similar to yours.

 

However,

>> switch has approx 330 active vlans

This looks like to be an high number for a device like yours that is intended for small business not ISP level.

How many MAC addresses are learned ?

 

Hope to help

Giuseppe

 

Approx 2400 to 2500 mac address has been learning.

And I have around 1500 total clients distributed from the switch with fiber
and wl connectivity.

And I am also getting drop events on multiple ports
Ss is attached for reference

Hello,

the number of drop events when compared to total packets received leads to a low drop probability that should not be an issue

 

Hope to help

Giuseppe

 

View solution in original post