Best way to troubleshoot loopback on a Fast Ethernet

[adam.roth]

Verizon wanted us to test a MetroEthernet circuit.  They said they did a loop back to me.  I was up/up on Fast Ethernet.  Normally when you do a loopback and do a show int with a serial , you can see (looped).  How do you see a looped with a Fast Ethernet?

[Ganesh Hariharan]

Verizon wanted us to test a MetroEthernet circuit.  They said they did
a loop back to me.  I was up/up on Fast Ethernet.  Normally when you do
a loopback and do a show int with a serial , you can see (looped).  How
do you see a looped with a Fast Ethernet?

Check out the below link hope to help !!

https://support.neoteris.com/techpubs/software/nog/nog-interfaces/download/fe-ge-loopback2.pdf

http://www.cisco.com/en/US/docs/ios/12_1/interface/command/reference/irdinter.html

Ganesh.H