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regisclover
Beginner

Catalyst 2960 dropping traffic after new device installed

We are having an issue on a 2960 switch when we add a new device to the switch (in this case a printer), the rest of the devices drop.

They only come back if we reboot the switch.

Any ideas?

6 REPLIES 6
cadet alain
Advisor

Hi,

what do you mean by all other drop?

Regards.

Alain.

Don't forget to rate helpful posts.

the other devices - pc's - lose connectivity

Leo Laohoo
VIP Community Legend

Are you sure the printer is not connected to a different switch and connected to the 2960?  Sounds like you have a broadcast storm happening.

we are directly connecting it to the 2960 which in turn is connected to a 3560 which is our root switch

any way to turn off broadcasting?

Leo Laohoo
VIP Community Legend

Try this command in the interface where this printer is connected "spanning-tree bpduguard enable".  This command will  shut down (err-disable) the port if the switch can "hear" BPDU coming into the said port.  You can re-enable the port by issuing the commands "shutdown" followed by a "no shutdown".

Does your 2960 have a Gig port to do some trivial testing?  If it does, connect the printer to the Gig port and issue the following commands:

1.  interface Gig0/1;

2.  media rj

3.  end (this command will take you out of configuration mode)

4.  test cable tdr int Gig0/1

5.  Wait for about 5 to 7 seconds

6.  sh  cable tdr int Gig0/1

7.  conf t

8.  int Gig0/1

9.  media auto

10.  end

Post the output for the "sh cable tdr int Gig0/1" command.

kapathak
Cisco Employee

Hello Regis,

Can you tell us if we see the mac addresses of the desktops in the CAM after you add this device?

What VLAN does the printer to belong to? What VLAN are the desktops in?

Also, can you share the output of the following when the issue occurs:

- sh spann de ac | i exe|Number of top|from

- Config of port where the printer is connected

Cheers!

Kapil