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How to Manually Tune SFM Links

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TitleHow to Manually Tune SFM Links
Objective
How to Manually tune SFM links
Environment
MLX
Procedure
1.) Collect data regarding which SM Link is down:

SFM Link down: SFM 3/FE 3/Link 65, LP 26/TM 2/Link 24 DOWN
  • This data is in 1-Base meaning all values start with 1 and not 0

SSH@FTWN01DCCOB#sho sfm-li al e        
 SFM#/FE# | FE link# | LP#/TM# | TM link# | link state
----------+----------+---------+----------+------------
   3 / 3 | 65 | 26 / 2 | 24 | DOWN


2.) Disable dm link: if you do not see Link Management disabled, please do “dm link” one more time.

telnet@NetIron MLX-32 Router#dm link
Link Management disabled

3.)Disable sysmon

no sysmon tm link
no sysmon fe link


SFM TUNING:

4.) Then power-on the link
5.) 
Check the link status

show sfm-link all

6.) 
If link is UP, Tune on MP with below command: will take 5 ~ 10 minutes

dm rw-snm 2 2 calibrate-serdes 64 0 2 1 1 2 5 3 0 32 0 32
blue->    link index (0 base)

7.) Update RX parameters on SFM link at MP console
If RX parameters output is  “zcnt: 24  z1cnt:dfelth: 16  tlth: 17  g1cnt: 1
                  Update new parameter with command dm rw-snm 2 2 set-rx-serdes-params-link 64 24 2 16 17 1

LP TUNING:

8.) If the tuning from MP does not bring up the link, please try the below command for tuning on LP side.: will take 5 ~ 10 minutes

LP-26#diag tm calibrate-serdes 1 23 1 2 1 5 0 3 0 32 0 32
blue ->    link index (0 base)

9.) Update RX parameters on LP link at LP console

If RX parameters output is  “zcnt: 24  z1cnt:dfelth: 10  tlth: 11  g1cnt: 1
Update new parameter with command: LP-1#diag tm set petra-ser 1 23 rx 24 2 10 11 1

10.) Enable sysmon
11.) Enable ‘dm link’

The tuning(calibrate-serdes) output is similar as below and you can get RX parameters output below:

10-+PPPPbboooo..  ....oobbPPDDBBBBMMMXXXXXXXXXXXXXXXX|   '?'  No data
   |PPbboo......  ..oobbPPDDDDBBMMMMBXXXXXXXXXXXXXXXX|   ' ' BER <10-9
   |PPbboo...... +..oobbPPDDDDBBMMMMBXXXXXXXXXXXXXXXX|   '.' BER ~10-9
   |bboooooo....oobbbbPPDDDDBBBBMMBBDXXXXXXXXXXXXXXXX|   'o' BER ~10-8
   |bboooooo....oobbbbPPDDDDBBBBMMBBDXXXXXXXXXXXXXXXX|   'b' BER ~10-7
 5-+PPbbbbbbbbbbbbPPPPDDBBBBBBMMBBDDPXXXXXXXXXXXXXXXX|   'P' BER ~10-6
   |PPbbbbbbbbbbbbPPPPDDBBBBBBMMBBDDPXXXXXXXXXXXXXXXX|   'D' BER ~10-5
   |DDDDPPPPPPPPPPDDDDBBBBMMMMBBPPbbXXXXXXXXXXXXXXXXX|   'B' BER ~10-4
   |DDDDPPPPPPPPPPDDDDBBBBMMMMBBPPbbXXXXXXXXXXXXXXXXX|   'M' BER ~10-3
   |DDDDDDDDDD..DDDDBBBBMMMMBBPPbbXXXXXXXXXXXXXXXXXXX|   'W' BER ~10-2
 0-+DDDDDDDDDD..DDDDBBBBMMMMBBPPbbXXXXXXXXXXXXXXXXXXX|   'X' BER >10-2
   -+----+----+----+----+----+----+----+----+----[TLTH]
    |    |    |    |    |    |    |    |    |    |   
     0    5   10   15   20   25   30   35   40   45               
valid: 1
tlth: 13
dfelth: 8
tlth_margin: 1
dfelth_margin: 1

Zcnt:   24, Z1cnt:  2, Dfelth: 8, Tlth:   13, G1cnt:  1

Summary:
| Link # | Zcnt | Z1cnt | Dfelth | Tlth | G1cnt | Dfelth margin | Tlth margin |
-------------------------------------------------------------------------------
|       55    |  24  |   2      |        8   |  13  |    1  |       1      |       1     |
 
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