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10 avril 2012 2 10 /04 /avril /2012 16:58

Small tips for analyse the fabric stats. I mean packets stats (IN/OUT/Drops) between each PFE and the Fabric. 

Usually fabric stats can be observe by using the following cli command. Remember, that there are only 2 streams at fabric level: High and Low (aka. Priority Drop). 



sponge@bob>show class-of-service fabric statistics summary 

Destination FPC Index: 0, Source FPC Index: Summarized from all source FPC's

 Total statistics:   High priority           Low priority

    Packets:             448626385             1365903575

    Bytes  :          598687578257          1861601724122

    Pps    :                    40                   3996

    Bps    :                 20912                5470976

 Tx statistics:      High priority           Low priority

    Packets:             448626385             1365903575

    Bytes  :          598687578257          1861601724122

    Pps    :                    40                   3996

    Bps    :                 20912                5470976

 Drop statistics:    High priority           Low priority

    Packets:                     0                      0

    Bytes  :                     0                      0

    Pps    :                     0                      0

    Bps    :                     0                      0


The above command gives the total statistics from all FPC to a given Destination FPC (here the FPC 0). To collect the stats from one given FPC to another one use:

 


sponge@bob> show class-of-service fabric statistics destination 0 source

Destination FPC Index: 0, Source FPC Index: 3

 Total statistics:   High priority           Low priority

    Packets:              42445974              439161456

    Bytes  :           71944097695           604147953760

    Pps    :                     0                   3995

    Bps    :                     0                5470681

 Tx statistics:      High priority           Low priority

    Packets:              42445974              439161456

    Bytes  :           71944097695           604147953760

    Pps    :                     0                   3995

    Bps    :                     0                5470681

 Drop statistics:    High priority           Low priority

    Packets:                     0                      0

    Bytes  :                     0                      0

    Pps    :                     0                      0

    Bps    :                     0                      0


To collect more accurate information (per PFE fabric stats and not per FPC as above) you can use the following hidden command. 

For MX series:

show chassis fabric statistics rates detail <Fabric-Plane-Num> | match "DPC<Slot>PFE|put"

 

For T series:  

show chassis fabric stats rates detail <SIB-Num> | match "FPC<slot>_|put"

You can call back the same command for each active Fabric Plane or SIB

Ex. for MX Fabric Plane 2, MPC slot 3.


sponge@bob> show chassis fabric statistics rates detail 2 | match "DPC3PFE|put"    

Input Link          State     vld/sec    req/sec    gnt/sec    drops/sec

DPC3PFE0->CB1F0_03_0 up      0000000000 0000000000 0000000000 0000000000

DPC3PFE1->CB1F0_03_1 up      0000007601 0000007601 0000000000 0000000000

DPC3PFE2->CB1F0_03_2 up      0000000000 0000000000 0000000000 0000000000

DPC3PFE3->CB1F0_03_3 up      0000014374 0000014373 0000000000 0000000000

Output Link          State     vld/sec    req/sec    gnt/sec    drops/sec

CB1F0_03_0->DPC3PFE0  up      0000000000 0000000000 0000000000 0000000000

CB1F0_03_1->DPC3PFE1  up      0000000000 0000000000 0000007600 0000000000

CB1F0_03_2->DPC3PFE2  up      0000000000 0000000000 0000000000 0000000000

CB1F0_03_3->DPC3PFE3  up      0000000000 0000000000 0000014373 0000000000


The stats are in cells/sec (JCELL is, if i'm remember, a 64 bytes size container).


For the traffic DPCxPFEx --> CBxFx (F for SF chip hosted by the sCB) :

- vld/sec : valid cells per second sent by the PFE. 

- req/sec : valid cells sent to the fabric

- gnt/sec : valid cells received from the fabric.

- drops/se : cells drops (in or out) 

      
For the traffic CBxFx --> DPCxPFEx :

- vld/sec : valid cells per second sent by the SF chip. 

- req/sec : valid cells sent to the PFE

- gnt/sec : valid cells received from the PFE

- drops/se : cells drops (in or out) 

 

NB.: The traffic from and to a PFE should be equally distributed over each fabric plane or sib. 

 

For T series the output is a little bit different: 

 


star@patrick> show chassis fabric stats rates detail 3 | match "FPC2_|put"   

Input Link              State vld/sec    req/sec    gnt/sec    drops/sec

FPC2_T->SIB3_F0,04      UP    0000020570 0000020573 0000001413 0000000000

FPC2_B->SIB3_F0,05      UP    0000000000 0000000000 0000000002 0000000000

Output Link              State vld/sec    req/sec    gnt/sec    drp/sec

SIB3_F0,02->FPC2_B       UP    0000000000 0000000002 0000000000 0000000000

SIB3_F0,03->FPC2_T       UP    0000001411 0000001413 0000020588 0000000000


 

NB. : 

The _T means PFE 0 of the given FPC

The _B means FPE 1 of the given FPC


All of those commands are very useful when troubleshooting packet drops issue, gongestion problem, HW issue or during stress tests of new HW or SW. I'm currently written an op script, for MX, that should aggregate in only one command all the stats from all fabric planes but it's not so easy because it's an hidden command that doesn't have an XML output...

 

David. 

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