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Contributor
Posts: 26
Registered: ‎01-20-2011

stat_lc_rx - Link control frames

Can someone tell me what this counter indicates when it's clocking up on certain ports?  I know what the various link control frames are but I don't know what this specific counter is telling me, if anything.  It does seem to go hand in hand with ports that are experiencing congestion.  For example:

stat_wtx                1036053469  4-byte words transmitted
stat_wrx                144865388   4-byte words received
stat_ftx                284207274   Frames transmitted
stat_frx                691755505   Frames received
stat_c2_frx             0           Class 2 frames received
stat_c3_frx             691745666   Class 3 frames received
stat_lc_rx              4600        Link control frames received
stat_mc_rx              0           Multicast frames received
stat_mc_to              0           Multicast timeouts
stat_mc_tx              0           Multicast frames transmitted
tim_rdy_pri             2           Time R_RDY high priority
tim_txcrd_z             4283176     Time TX Credit Zero (2.5Us ticks)
tim_txcrd_z_vc  0- 3:  0           0           0           2134951  
tim_txcrd_z_vc  4- 7:  2148225     0           0           0        
tim_txcrd_z_vc  8-11:  0           0           0           0        
tim_txcrd_z_vc 12-15:  0           0           0           0      

Thanks,

G.L.

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: stat_lc_rx - Link control frames

I honestly don't know, but your asking this in regards to performance problems?

If so, look at counters like c3 class discard due to timeouts,  tim_txcrd_z and received/sent frames.

But first reset the counters as the values can wrap round very quickly and are meaningless if you don't know when that happend.

Than take another look an hour or so later.

I prefer the command portstats64show as those value take considerable longer to wrap round.

Contributor
Posts: 26
Registered: ‎01-20-2011

Re: stat_lc_rx - Link control frames

Well, they are having problem but at this point we don't know if the congestion is part of it.  This is in a BladCenter H with PS704 blades and they have various link issues, CRCs and other odd behavior but I think a majority of it has to do with them not having things setup for 'best practice'.   They're not discarding any frames, so it's not choking the pipe to that point.  They have some things to flash and retest and if that fails then we'll be gathering a fresh set of support saves as the ones I currently have are stale and not baselined at all.   Thanks for the reply!

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: stat_lc_rx - Link control frames

I'm not familiar with IBM gear, but are those perhaps the first 8G devices or longdistance involved?

If so, look at the portcfglongdistance setting and compare those to the IBM advised setting.

Contributor
Posts: 26
Registered: ‎01-20-2011

Re: stat_lc_rx - Link control frames

Well, they are technically first gen 8G devices for the Bladecenter (Emulex Tetra HBAs) , and the BCs have thier own special set of problems at 8G.  This is not a long distance haul either, just within the same datacenter.

G.L.

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: stat_lc_rx - Link control frames

Made an error, I wrote portcfglongdistance I ment to write portfcgfillword.

If they are 8G devices how is the fill word set against that/those port(s) and what does IBM recommend?

Contributor
Posts: 26
Registered: ‎01-20-2011

Re: stat_lc_rx - Link control frames

Fill word is 1 for the internal blade facing ports, and Brocades reccomended for the external uplinks is 3.  3 seems to work the best as it's a catch all setting. 

Regular Contributor
Posts: 178
Registered: ‎04-21-2008

Re: stat_lc_rx - Link control frames

Hi -

portcfgfillword is set to 1 on internal switchs because it's an IBM recommandation / default config.

Have a look at the following and see if your configuration is concerned or not :

http://www-947.ibm.com/support/entry/portal/docdisplay?lndocid=MIGR-5087103

Hope this helps

Kind regards

--

david

Contributor
Posts: 26
Registered: ‎01-20-2011

Re: stat_lc_rx - Link control frames

Heh heh, thanks, but I'm one of the ones who came up with that document. I'm with product engineering for IBM BladeCenters and specialize in the FC side of things.  I'm really just trying to find out what that specific counter is telling me.

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: stat_lc_rx - Link control frames

It counts the received link control frames like,

ACKAcknowledge data frame (success)
F_BSYFabric busy
F_RJTFabric frame reject
P_BSYPort busy
P_RJTPort frame reject

I wouldn't worry about it in case there ack''s.

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