Troubleshooting a bad cable
Bad cables can cause the stack port to flap or go down completely. If there are an excessive number of port flaps, the port is disabled and the following log message appears:
W 10/06/00 23:23:16 02560 chassis: ST4–CMDR: Stack port 1 disabled due to excessive errors. Check cable. To reenable use 'stacking member 4 stack-port 1 enable'.
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When this occurs, the
show stacking stack-portscommand shows the port with a status of “Disabled”.Displaying a disabled stack port
switch# show stacking stack-ports Member Stacking Port State Peer Member Peer Port ------------------------------------------------------ 1 1 Up 5 2 1 2 Up 2 1 1 3 Up 3 3 1 4 Up 4 3 2 1 Up 1 2 2 2 Up 3 1 2 3 Up 4 4 2 4 Up 5 3 3 1 Up 2 2 3 2 Down 0 0 3 3 Up 1 3 3 4 Up 5 4 4 1 Disabled 0 0 4 2 Up 5 1 4 3 Up 1 4 4 4 Up 2 3 5 1 Up 4 2 5 2 Up 1 1 5 3 Up 2 4 5 4 Up 3 4
If the cable failure is more solid, the port is in the DOWN state. The logs show any transition.
I 10/07/00 06:01:15 02559 chassis: ST4-STBY: Stack port 3 is now off-line. I 10/07/00 06:01:16 02559 chassis: ST3-CMDR: Stack port 3 is now off-line. I 10/07/00 06:01:16 02559 chassis: ST2-MMBR: Stack port 1 is now off-line. I 10/07/00 06:01:15 02559 chassis: ST5-MMBR: Stack port 2 is now off-line. I 10/07/00 06:01:15 02558 chassis: ST2-MMBR: Stack port 1 is now on-line. I 10/07/00 06:01:12 02558 chassis: ST5-MMBR: Stack port 2 is now on-line. I 10/07/00 06:01:10 02558 chassis: ST4-STBY: Stack port 3 is now on-line.
The following example shows member 3, port 2, which should be connected to member 4, port 1. The ports are down because the cable is bad or disconnected.
Displaying that two ports are down due to a bad connectionswitch# show stacking stack-ports Member Stacking Port State Peer Member Peer Port ------------------------------------------------------ 1 1 Up 5 2 1 2 Up 2 1 1 3 Up 3 3 1 4 Up 4 3 2 1 Up 1 2 2 2 Up 3 1 2 3 Up 4 4 2 4 Up 5 3 3 1 Up 2 2 3 2 Down 0 0 3 3 Up 1 3 3 4 Up 5 4 4 1 Down 0 0 4 2 Up 5 1 4 3 Up 1 4 4 4 Up 2 3 5 1 Up 4 2 5 2 Up 1 1 5 3 Up 2 4 5 4 Up 3 4
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The solution in both cases is to ensure that the cable is firmly connected at both ends. If the problem continues, replace the cable. It is possible that there could be a problem with the stack port itself. To confirm this possibility, install a known good cable to see if that cable also fails.
The port state is not UP until both ends of the cable are connected and the cable has been validated as a genuine cable.
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To view the statistics on the physical port, execute the
show techcommand in member-context 4. The following examples show the types of information displayed.Displayingshow techoutputPort Number : 1 State : Available Last Event : Available Start Req : 1 NE Present : 1 HPID Good : 1 HPID Fails : 0 FE Present : 1 Rem Dev Rdy : 1 ESSI Link : 1 ESSI Good : 1 ESSI Fails : 0 ESSI TX En : 1 ICL Good : 1 ICL Enabled : 1 LP Local RDY: 1 LP Rem RDY : 1 LP DONE : 1 ICL FailCnt : 0 (10 second interval) ICL FailCnt : 0 (10 minute interval) NE Presence HW : 1 FE Presence HW : 1 Rem Dev Rdy HW : 1 Local Dev Rdy HW : 1 Asserted NE Presence HW : 1 Asserted FE Presence HW : 1 Asserted Rem Dev Rdy HW : 1 Phy Frame Errors : 0 Invalid Status Errors : 0 Invalid Packet Type Errors : 0 Incomplete Packet Errors : 0 Checksum Errors : 0 ESSI Flow Out This Port (HW) : 0x2
Displaying trace information for a portTrace for Port 1 [ 0] [Info ] Start Request Received (Empty) [0] [ 1] [Info ] Waiting for Stack Module Good (Empty) [0] [ 2] [Info ] Stack Module Good Received (Empty) [0] [ 3] [Info ] Cable Insertion Detected (Empty) [1] [ 4] [Info ] Re-enable NE Present Int [487] [ 5] [Info ] Starting Cable HPID Validation (Inserted) [488] [ 6] [Info ] Skipping Cable HPID Validation (Inserted) [488] [ 7] [Info ] Far End Insertion Detected (Valid) [988] [ 8] [Info ] Polling for ESSI phy link up (Valid) [988] [ 9] [Info ] ESSI Link Up [9988] [10] [Info ] ESSI Link Good (Valid) [9988] [11] [Info ] ESSI Linked at 9988 ms [9988] [12] [Info ] Remote Device Ready Detected (Valid) [10898] [13] [Info ] ICL Change Request Enable (Cable Ready) [10898] [14] [Info ] Detected Remote Ready Drop. (Cable Ready) [12651] [15] [Info ] ICL Good. Behind. Partner ready. (Cable Ready) [12988] [16] [Info ] ICL GOOD received at 2091 ms [12988] [17] [Info ] Partner LP ready. (Cable Ready) [13980] [18] [Info ] Set Device Ready. (Cable Ready) [13987] [19] [Info ] ESSI Link Verified [13988] [20] [Info ] ESSI Able to Transmit (Cable Ready) [13988] [21] [Info ] ESSI Verified at 3091 ms [13988] [22] [Info ] Cable Available (Available) [13988]