Cisco DS-C9124-K9 Troubleshooting Guide - Page 522

Using Cisco MDS 9000 Family Tools Appendix B Troubleshooting Tools and Methodology Send documentation comments to [email protected] 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. Note FC traceroute will only work across EISL links. Example B-2 fctraceroute Command switch# fctrace fcid 0xef0000 vsan 1 Route present for : 0xef0000 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) Note The values rendered by the FC traceroute process do not reflect the actual latency across the switches. The actual trace value interpretation is shown in the example below. switch# show fcns database vsan 600 VSAN 600 FCID TYPE PWWN (VENDOR) FC4-TYPEFEATURE 0xeb01e8 NL 210000203767f7a2 (Seagate) scsi-fcptarget 0xec00e4 NL 210000203767f48a (Seagate) scsi-fcp 0xec00e8 NL 210000203767f507 (Seagate) scsi-fcp Total number of entries = 3 switch# fctrace fcid 0xeb01e8 vsan 600 Route present for 0xeb01e8 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 OL-9285-05