marginal links involve the connection between the switch and the edge device. Isolating the exact cause of a marginal link involves analyzing and testing many of the components that make up the link (including the switch port, switch SFP, cable, the edge device, and the edge device SFP).
First run PortErrShow to display port error report
COMP_FCSW01A:root> porterrshow
frames enc crc too too bad enc disc link loss loss frjt fbsy
tx rx in err shrt long eof out c3 fail sync sig
=====================================================================
0: 3.2g 2.6g 0 1 0 0 1 9.3m 10 35 2.0k 4 0 0
1: 24k 12k 0 0 0 0 0 2.0g 0 3 592m 2 0 0
2: 79k 181k 0 0 0 0 0 1.0g 0 294 34m 2 0 0
3: 3.7g 3.2g 0 0 0 0 0 175m 27 204 121m 3 0 0
4: 1.8g 2.4g 1.4k 396 3 0 241 690m 48 221 21m 3 0 0
5: 3.2g 3.9g 1.1k 81 0 0 81 504m 27 222 101m 2 0 0
6: 7.0m 3.0m 0 0 0 0 0 1.8g 1 232 2.3g 66 0 0
7: 3.0g 4.2g 0 0 0 0 0 292m 21 319 9.8m 4 0 0
8: 2.2m 1.2m 0 0 0 0 0 8.1m 0 69 1.2k 62 0 0
9: 898m 2.0g 0 0 0 0 0 9.2m 5 79 1.8k 74 0 0
10: 1.4g 4.2g 0 0 0 0 0 1.9m 18 320 1.1k 70 0 0
11: 2.6g 864m 0 0 0 0 0 5.5m 24 275 8.1m 6.4m 0 0
12: 750m 2.2g 0 0 0 0 0 8.2m 3 67 1.2k 60 0 0
13: 1.2m 650k 0 0 0 0 0 6.4m 1 18 305 16 0 0
14: 2.1g 3.9g 0 0 0 0 0 290k 0 2 5 0 0 0
15: 619k 348k 0 0 0 0 0 2.7m 0 20 375 15 0 0
16: 0 0 0 0 0 0 0 0 0 3 0 0 0 0
17: 0 0 0 0 0 0 0 0 0 2 0 0 0 0
18: 2.3g 2.8g 0 0 0 0 0 16k 22 27 25 0 0 0
19: 5.5k 60k 0 0 0 0 0 5.5m 0 138 108m 11 0 0
20: 174k 332k 4.0k 454 72 0 443 3.2g 300 566 2.0g 17 0 0
21: 0 0 0 0 0 0 0 0 0 2 0 0 0 0
22: 3.8m 2.0m 0 0 0 0 0 1.4g 0 137 1.5g 2 0 0
23: 902m 2.5g 0 0 0 0 0 2.1g 28 652 53m 1 0 0
24: 165k 578k 0 0 0 0 0 21k 0 1.0k 529 2 0 0
25: 3.3g 1.5g 0 0 0 0 0 196m 2 265 8.0m 2 0 0
26: 3.4g 2.6g 0 0 0 0 0 2.7g 3 593 68m 1 0 0
27: 936m 2.7g 0 0 0 0 0 6.7m 7 50 2.3k 46 0 0
28: 2.7g 1.5g 0 0 0 0 0 8.0m 2 51 2.5k 48 0 0
29: 3.7g 2.7g 0 0 0 0 0 1.3g 27 265 1.6g 265 0 0
30: 77k 126k 0 0 0 0 0 23m 0 202 2.5m 0 0 0
31: 1.5g 4.2g 0 0 0 0 0 42k 61 17 17 5 0 0
2. From the output, search for relatively high number of errors such as CRC errors or ENC_OUT errors, or if there are a steadily increasing number of errors to confirm a marginal link.
3. If you suspect a marginal link, isolate the areas by moving the suspected marginal port cable to a different port on the switch. Reseating of SFPs may also cure marginal port problems. If the problem stops or goes away after changing the port, then the switch port or the SFP is marginal. Go proceed with next step to have the SFP replaced.
If the problem does not stop or go away, proceed to replace the FC cable.
4. Replace the SFP on the faulty port.
