Cisco 9134 - MDS Multilayer Fabric Switch Troubleshooting Manual page 522

Using Cisco MDS 9000 Family Tools
S e n d d o c u m e n t a t i o n 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
Use FC Trace by providing the FC ID, the N port, or the NL port WWN of the destination. The frames
are routed normally as long as they are forwarded through TE ports. After the frame reaches the edge of
the fabric (the F port or FL port connected to the end node with the given port WWN or the FC ID), the
frame is looped back (swapping the source ID and the destination ID) to the originator.
If the destination cannot be reached, the path discovery starts, which traces the path up to the point of
failure.
The FC Trace feature works only on TE Ports. Make sure that only TE ports exist in the path to the
destination. If there is an E Port in the path:
The FC Trace frame will be dropped by that switch.
•
The FC Trace will time out in the originator.
•
Path discovery will not start.
•
FC traceroute will only work across EISL links.
Note
Example B-2
switch# fctrace fcid 0xef0000 vsan 1
Route present for :
20:00:00:05:30:00:59:de(0xfffcee)
Latency: 0 msec
20:00:00:05:30:00:58:1e(0xfffc6c)
Timestamp Invalid.
20:00:00:05:30:00:59:1e(0xfffcef)
Latency: 0 msec
20:00:00:05:30:00:59:1e(0xfffcef)
Latency: 174860 msec
20:00:00:05:30:00:58:1e(0xfffc6c)
The values rendered by the FC traceroute process do not reflect the actual latency across the switches.
Note
The actual trace value interpretation is shown in the example below.
switch# show fcns database vsan 600
VSAN 600
--------------------------------------------------------------------------
FCID
--------------------------------------------------------------------------
0xeb01e8
0xec00e4
0xec00e8
Total number of entries = 3
switch# fctrace fcid 0xeb01e8 vsan 600
Route present for
2000000530007ade(0xfffcee) ---> MDS originating the trace
Latency 0 msec
2000000c30575ec0(0xfffced) --->first hop MDS towards destination FCID
Latency 30820 msec
2000000c306c2440(0xfffceb) --> MDS which connects directly to the traced FCID (0xeb01e8)
Latency 0 msec
2000000c306c2440(0xfffceb) -->idem, but looped around
Latency 0 msec
2000000c30575ec0(0xfffced) --> first hop MDS on the return path from traced FCID to
originor
switch#
Cisco MDS 9000 Family Troubleshooting Guide, Release 3.x
B-6
fctraceroute Command
0xef0000
TYPE PWWN
NL 210000203767f7a2 (Seagate)
NL 210000203767f48a (Seagate)
NL 210000203767f507 (Seagate)
0xeb01e8
Appendix B Troubleshooting Tools and Methodology
(VENDOR) FC4-TYPEFEATURE
scsi-fcptarget
scsi-fcp
scsi-fcp
OL-9285-05