Multicast & Broadcast Loop Detection and Resolution

[anthonypoon]

Dear Experts,

Our company found IP phone call choppy sounds, Cisco IP phone autoreboot, ACD agent phone auto-logout and call drop, slower network access since last Friday. Our vendors has checked the followings:

1. WAN links utilization is normal

2. Switches CPU utilization is not high

3. Wireshark traces intermittent HSRP multicasts from routers / server broadcast burst

4. Some switchports flashing at the same time frequently

5. Switchports is set with auto-qos & voice packets have been tagged with EF

6. IPT system should be working normally

Can any body can advise me how to identify looping source and how to resolve the looping issue? Please enlighten.

Thanks.

Anthony

[marce1000]

  - Activate syslogging to  a central  server on all your switches , look for weird  error messages afterwards.

 M.

[balaji.bandi]

Adding to other post :

1. Firsrt i will look before Friday what were the major changes done in the network. (if all working as expected before Friday problem reported)

2. i will review the config with the base config with current config any changes.

3. when was the last time the devices are rebooted or patched ?

4. Good to have high level topology for us to look how your network and where the issue going to be.

5. also provide evidence of logs and config

waiting for input further asistance to provide,.

[paul driver]

Hello

How many devices are you talking about?

Are you ruining any multicast applications
Do you have any storm control/port security applied to the access switches ports?