Cisco switch, how to determine MAC address of connected device or wake device up

cisconetworkingswitch


switch1#show interfaces descri
...
Fa0/13 up up
Fa0/14 down down
Fa0/15 up up
...

(the lights are also on on both ports 13 and 15)

However:

switch1#show mac-address-table
24 x.dc15.93a9 DYNAMIC Fa0/13
24 x.9931.296d DYNAMIC Fa0/11
24 x.2196.cf24 DYNAMIC Gi0/1
24 x.a947.fb81 DYNAMIC Fa0/11
24 x.b954.90c2 DYNAMIC Fa0/8
24 x.b976.a45c DYNAMIC Fa0/2
24 x.8f1c.f11b DYNAMIC Fa0/11
24 x.ba8e.f467 DYNAMIC Fa0/11
28 x.2196.cf24 DYNAMIC Gi0/1
28 x.f08a.6025 DYNAMIC Fa0/20
28 x.f08a.6026 DYNAMIC Fa0/19
28 x.f08a.6027 DYNAMIC Fa0/22
21 x.2196.cf24 DYNAMIC Gi0/1
20 x.2196.cf24 DYNAMIC Gi0/1

i.e. nothing for port 15!
How to determine the MAC address of this port or how to wake up the device? Once again, the lights on both ports are green.

Best Answer

You could drop the entire MAC table and allow the device to 're-learn' all connected devices (should happen on the first received packet)

clear mac-address-table dynamic

http://www.cisco.com/en/US/docs/ios/12_3t/lanswitch/command/reference/lan_a1gt_ps5207_TSD_Products_Command_Reference_Chapter.html

If the device connected to port 15 does not send data due to it being "asleep" then bring the port down then back up. The re-detection of the link maybe enough to cause an IP communication to occur.

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