Cisco 3560 dropout

Posted on 2007-07-24
Medium Priority
Last Modified: 2008-02-22
I just installed a new Cisco 3560 Gigabit 48 port switch. Since it has been installed, at least once per day the LAN seems to lose connection for a split second (or long enough for our accounting system to lose connection to the database.) which requires a restart to re-gain connection. I have started a TAC case with Cisco but for the first time I am not getting very good service from them. Are there any ideas on what I can do to determine where the problem is. I have enabled syslogging and since then I haven't experienced the problem, I estimate it will happen sometime today and when it does I want to make sure the logging is configured correctly and it will capture the needed info.
Question by:Bill Warren
  • 2
LVL 57

Accepted Solution

giltjr earned 1000 total points
ID: 19561884
Make sure that only ports that carry VLAN tagged frames are setup as trunk ports.  All other ports should be setup in switchport mode access with the correct VLAN.

LVL 17

Assisted Solution

mikecr earned 1000 total points
ID: 19640706
Do the following:

config t
logging on
logging buffered informational
logging buffered 6
logging buffered 32768
logging facility local6

Let it run until it happens again and do a "show log" and post it here. Also do you have any uplinks to other switches or is this the only switch with servers on it?

Author Comment

by:Bill Warren
ID: 19641095
There were uplinks to 2 switches and a firewall. they had me run this on those 3 ports
config t
interface GigabitEthernet0/##
no spanning-tree portfast
wr mem

Author Comment

by:Bill Warren
ID: 19641108
Since then I haven't had an incident so I'm thinking that the issue may be resolved... I want to wait a while longer to see if it happens again.

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