Link_Failure Or Not Connected - Cisco MDS 9000 Series Troubleshooting Manual

Troubleshooting Fx Port Connectivity
S e n d c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m .

Link_Failure or Not Connected

The following example shows the interface down as a result of a link failure or disconnect.
switch# show interface fc7/31
fc7/31 is down (Link_Failure or not connected)
The message "Link_Failure" or "not connected" can happen if nothing is connected to the specific
interface (as in the case of a broken fiber), or if there is no bit synchronization between the switch
interface and the Nx port directly connected. (In the case of a broken fiber, if only the TX path from the
F port to the N port is broken, the switch interface will still have an operational Rx path, and so will still
obtain bit synchronization from the bit stream received from the N port. It will also be able to recognize
an incoming NOS from the N port and reply with an OLS. But because the transmitted OLS never
reaches the N port the R_T_TOV timer expires. In this scenario the status of the port will also show
"Link_Failure or not connected". )
The key difference between this case and the "no bit synchronization" case, is that the input and output
counts for OLS & NOS increment (as there is bit synchronization but no word synchronization). In such
a state, you can check that the Tx path from switch to the Rx input on N port interface is properly
connected. A faulty transmitter on the switch's SFP or a faulty receiver on the N port's SFP could also
cause the issue.
Cisco MDS 9000 Family Troubleshooting Guide
3-14
0 frames output, 0 bytes, 0 discards
Received 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Transmitted 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Counter Values (5 minute averages):
0 frames input, 0 bytes, 0 discards
0 runts, 0 jabber, 0 too long, 0 too short
0 input errors, 0 CRC, 0 invalid transmission words
0 address id, 0 delimiter
0 EOF abort, 0 fragmented, 0 unknown class
0 frames output, 0 bytes, 0 discards
Received 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Transmitted 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Hardware is Fibre Channel
Port WWN is 21:9f:00:05:30:00:18:a2
Admin port mode is auto, trunk mode is on
vsan is 1
Beacon is turned off
Counter Values (current):
0 frames input, 0 bytes, 0 discards
0 runts, 0 jabber, 0 too long, 0 too short
0 input errors, 0 CRC, 0 invalid transmission words
0 address id, 0 delimiter
0 EOF abort, 0 fragmented, 0 unknown class
0 frames output, 0 bytes, 0 discards
Received 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Transmitted 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Counter Values (5 minute averages):
0 frames input, 0 bytes, 0 discards
0 runts, 0 jabber, 0 too long, 0 too short
0 input errors, 0 CRC, 0 invalid transmission words
0 address id, 0 delimiter
0 EOF abort, 0 fragmented, 0 unknown class
0 frames output, 0 bytes, 0 discards
Received 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Transmitted 0 OLS, 0 LRR, 0 NOS, 0 loop inits
Chapter 3 Troubleshooting Switch Level Issues and Interswitch Connectivity
OL-5183-02, Cisco MDS SAN-OS Release 1.3