BB Credits in Nexus 5500UP running Native FC

[ataranen]

We are running nexus 5548up with NX-OS 5.2(1) connected to MDS 9222i. The nexus ports are in native FC mode. The nexus FC port should support a maximum of 240 Receive BB Credits according to "show interface fc1/30 capabilities" command, and also according to the Cisco documentation: http://cisco.sitecelerate.com/en/US/docs/switches/datacenter/nexus5000/sw/release/notes/Rel_5_1_3_N2_1/Nexus5000_Release_Notes_5_1_3_N2.html

However my FC ports still don't accept more than 64 BB credits:

n5kup(config-if)# switchport fcrxbbcredit 65

fc1/30: (error) Invalid rxb2b credit for desired port-mode and rate-mode

n5kup(config-if)# switchport fcrxbbcredit 64

n5kup(config-if)#

I have tried putting all other ports out-of-service to make sure there is enough resources. Tried reducing the speed from 4Gb to 2Gb. Still the maximum BB credits that can be assigned is 64, not 240 as documented.

[vdsudame]

The problem is documented in the following caveat:

CSCub96331

Unable to configure bbcredit on nexus for values bigger than 64.

CCO Bug Toolkit:

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCub96331

This is documented as part of resolved caveats for 5.2.1.N1.1b release

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/release/notes/Rel_5_2_1_N1_1/Nexus5000_Release_Notes_5_2_1_N1.html#wp452031

hope this helps,

Vinayak