Re: constant FEC errors juniper mpc10e 400g

[Aaron Gould <aaron1 () gvtc com>]

fec cliff?  is there a level of fec erros that i should be worried about 
then?  not sure what you mean.

-Aaron

On 4/17/2024 2:46 PM, Matt Erculiani wrote:
> I'm no TAC engineer, but the purpose of FEC is to take and correct 
> errors when the port is going so fast that errors are 
> simply inevitable. Working as Intended.
>
> Easier (read: cheaper) to build in some error correction than make the 
> bits wiggle more reliably.
>
> No idea if that rate of increment is alarming or not, but you've not 
> yet hit your FEC cliff so you appear to be fine.
>
> -Matt
>
> On Wed, Apr 17, 2024 at 1:40 PM Dominik Dobrowolski 
> <dobrowolski.domino () gmail com> wrote:
>
>     Open a JTAC case,
>     That looks like a work for them
>
>
>     Kind Regards,
>     Dominik
>
>     W dniu śr., 17.04.2024 o 21:36 Aaron Gould <aaron1 () gvtc com>
>     napisał(a):
>
>         We recently added MPC10E-15C-MRATE cards to our MX960's to upgrade our core to 400g.  During initial testing of the 
> 400g interface (400GBASE-FR4), I see constant FEC errors.  FEC is new to me.  Anyone know why this is occurring?  Shown below, is 
> an interface with no traffic, but seeing constant FEC errors.  This is (2) MX960's cabled directly, no dwdm or anything 
> between them... just a fiber patch cable.
>
>
>
>         {master}
>         me@mx960> clear interfaces statistics et-7/1/4
>
>         {master}
>         me@mx960> show interfaces et-7/1/4 | grep rror | refresh 2
>         ---(refreshed at 2024-04-17 14:18:53 CDT)---
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors                    0
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate               0
>              FEC Uncorrected Errors Rate             0
>         ---(refreshed at 2024-04-17 14:18:55 CDT)---
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors                 4302
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate               8
>              FEC Uncorrected Errors Rate             0
>         ---(refreshed at 2024-04-17 14:18:57 CDT)---
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors                 8796
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate             146
>              FEC Uncorrected Errors Rate             0
>         ---(refreshed at 2024-04-17 14:18:59 CDT)---
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors                15582
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate             111
>              FEC Uncorrected Errors Rate             0
>         ---(refreshed at 2024-04-17 14:19:01 CDT)---
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors                20342
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate             256
>              FEC Uncorrected Errors Rate             0
>
>         {master}
>         me@mx960> show interfaces et-7/1/4 | grep "put rate"
>            Input rate     : 0 bps (0 pps)
>            Output rate    : 0 bps (0 pps)
>
>         {master}
>         me@mx960> show interfaces et-7/1/4
>         Physical interface: et-7/1/4, Enabled, Physical link is Up
>            Interface index: 226, SNMP ifIndex: 800
>            Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU Error: None, Loop Detect PDU Error: 
> None, Loopback: Disabled, Source filtering: Disabled,
>            Flow control: Enabled
>            Pad to minimum frame size: Disabled
>            Device flags   : Present Running
>            Interface flags: SNMP-Traps Internal: 0x4000
>            Link flags     : None
>            CoS queues     : 8 supported, 8 maximum usable queues
>            Schedulers     : 0
>            Last flapped   : 2024-04-17 13:55:28 CDT (00:36:19 ago)
>            Input rate     : 0 bps (0 pps)
>            Output rate    : 0 bps (0 pps)
>            Active alarms  : None
>            Active defects : None
>            PCS statistics                      Seconds
>              Bit errors                             0
>              Errored blocks                         0
>            Ethernet FEC Mode  :                 FEC119
>            Ethernet FEC statistics              Errors
>              FEC Corrected Errors               801787
>              FEC Uncorrected Errors                  0
>              FEC Corrected Errors Rate            2054
>              FEC Uncorrected Errors Rate             0
>            Link Degrade :
>              Link Monitoring                   :  Disable
>            Interface transmit statistics: Disabled
>
>            Logical interface et-7/1/4.0 (Index 420) (SNMP ifIndex 815)
>              Flags: Up SNMP-Traps 0x4004000 Encapsulation: ENET2
>              Input packets : 1
>              Output packets: 1
>              Protocol inet, MTU: 1500
>              Max nh cache: 75000, New hold nh limit: 75000, Curr nh cnt: 1, Curr new hold cnt: 0, NH drop cnt: 0
>                Flags: Sendbcast-pkt-to-re
>                Addresses, Flags: Is-Preferred Is-Primary
>                  Destination:10.10.10.76/30  <http://10.10.10.76/30>, Local: 10.10.10.77, Broadcast: 10.10.10.79
>
>         -- 
>         -Aaron
>
>
>
> --
> Matt Erculiani

--
-Aaron