Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

One VLAN has stopped communicating from one switch to my network core

I have a Cisco 4510 core switch connected to multiple data closets running 3750g and 3750x switches.  These are all fiber linked and configured for 802.1Q trunks.  We have numerous vlans and have had no trouble with communications before.  Now, we suddenly have one vlan (vlan 26) that has stopped communicating from one data closet to the rest of the network.  All other vlans are working fine from this switch and this vlan is working fine in the other data closets.  It is just this one area having the trouble.  The devices in this vlan can talk to each other within the problem data closet.  Any suggestions on how to fix this short of rebooting the data closet?


Everyone's tags (1)
Hall of Fame Super Gold

Try clearing the ARP table on

Try clearing the ARP table on the core switch.

New Member

try to shutdown/no shutdown

try to shutdown/no shutdown the interface. Also, check if the interface exists on that switch