Question regarding show int <port> counter details

[yanagawa_sadao]

              what are these messages meaning?

              what is the difference between these messages?

              BB credit to zero state    

              BB credit out of zero state

# show interface fc2/1 counter details

fc2/1

      3044036838792 frames, 4399283834724472 bytes received

      0 class-2 frames, 0 bytes received

      0 class-2 discards

      0 F_BSY frames, 0 F_RJT frames

          generated against class-2 frames

      0 port reject frames

      3043949808643 class-3 frames, 4399277317376852 bytes received

      24 class-f frames, 6517347620 bytes received

      0 discards, 0 errors received

      0 discards, 47 errors transmitted

      5478787589331 frames, 9065686909375884 bytes transmitted

      0 class-2 frames, 0 bytes transmitted

      5478700583841 class-3 frames, 9065681680545452 bytes transmitted

      47 class-3 frames discarded

      87005490 class-f frames, 5228830432 bytes transmitted

      0 class-f frames discarded

      0 multicast packets received, 0 transmitted

      0 broadcast packets received, 0 transmitted

      3044036813695 unicast packets received, 5478821932942 transmitted

      2 link failures, 1 sync losses,       0 signal losses

      0 primitive sequence protocol errors

      0 invalid transmission words

      0 invalid CRCs, 0 Delimiter Errors

      0 address identifier errors

      0 link reset protocol errors received

      3 link reset protocol errors transmitted

      4 Offline Sequence errors received

      4 Offline Sequence errors transmitted

     0 frames received that are shorter than

          the minimum allowable frame length

          regardless of the CRC error

      0 frames received that are longer than

          the maximum frame length and also have a

          CRC error

      0 waits due to lack of transmit credits

      0 frames received with length greater

          than what was agreed to in FLOGI/PLOGI

      0 frames received with length less than

          the minimum indicated by the frame header

      6 link reset responses received

      0 link reset responses transmitted

      0 non-operational sequences received

      5 non-operational sequences transmitted

      0 fragmented frames received

      0 frames received with EOF aborts

      0 unknown class frames received

      0 8b10b disparity errors

      47 frames discarded

      0 Exchange Link Parameters switch fabric

          internal link service request failures

      38822 transitions of BB credit out of zero state

      0 transitions of BB credit to zero state

     0 Enhanced Inter Switch Link (EISL) frames

          discarded

      0 framing errors

      0 F8 type LIP sequence errors received

      0 F8 type LIP sequence errors issued

      6 Non F8 type LIP sequence errors received

      4 Non F8 type LIP sequence errors issued

[Steven.langdale_2]

Hello Sadao

I'm not too sure why there isn't a corresponding number of transitions TO as there are OUT OF.  I've seen this a couple of times, and not had a good answer.

As for the number in "transitions of BB credit out of zero state", is it increasing and are you having performance problems?

The counter is basically telling you the amount of times you changed from have no buffer credits (and therefore no traffic can pass) to having some credits (allowing traffic to pass).

This can be normal on a busy link, or one sized too small.  It's only really an issue though if you think you are suffering from performance issues.

Thanks

Steven

[santkumd528]

have you looked at Cisco MDS family fabric CLI configuration guide (release 4.x ?)  . Look at section called buffer credits.

[yanasada]

Hello　steven,santkumd528

Thanks to the response.

steven
as you said Performance issuse has occurs.

santkumd528
I saw the CLI Configuration Guide.
There was no listed.

The log of the EMC community had the following display.

transitions of tx BB credit out of zero state
transitions of rx BB credit to zero state
https://community.emc.com/thread/165265?start=15&tstart=0

However,tx and Rx no longer display in version 4.2

If it were assumed below.
transitions of BB credit out of zero state = transitions of tx BB credit out of zero state
transitions of BB credit to zero state=transitions of rx BB credit to zero state

If increase the "transitions of BB credit out of zero state"
I think an increase in "transitions of BB credit to zero state" of the opposite switch.

"Transitions of BB credit to zero state" but this time was always 0.
This counter is not being used anymore?