In rare circumstances, in the C4948G switches that run Cisco IOS Software Release 12.2(25)EWA2 or later, which includes Cisco IOS Software Release 12.2(25)SG, one or more ports can get stuck without any receiving (Rx) or transmitting (Tx) capability. This usually happens upon quick successions of link-flaps in a very short interval.
The shut / no shut commands do not recover the port from this state. There are no messages logged in order to indicate this failure.
This problem is seen on these Catalyst switches:
C4948G RJ45 & SFP ports
C4948G-10GE RJ45 ports only
WS-X4506-GB-T RJ45 ports only
WS-X4013+TS RJ45 ports only
If the show interface status command output shows the Connected state, and the show platform hardware interface [mod/port] all command output shows MAC state is Down and rxInReset flag is set to "True" then Cisco bug ID CSCsc10017 is most likely the problem.
This is a software bug and there is no need to replace the hardware.
In order to workaround this issue, try to reload the switch.
This bug is fixed in these Cisco IOS software releases and later: