[j-nsp] interpreting 10Gb interface "PCS statistics" values

Michael Carey mcarey at kinber.org
Fri Oct 21 12:37:39 EDT 2016


When I've seen PCS statistical errors before, it pointed to either a
failing optic that needed replaced in our MX or a drastic change in optical
light levels caused by an OSP fiber issue.  How do your "show interface
diagnostic optic" levels look?

On Wed, Oct 19, 2016 at 7:40 PM, David B Funk <dbfunk at engineering.uiowa.edu>

> I've got a couple of 10Gig-eth interfaces (xe- on MX480) of which I'm
> trying to interpret the "PCS statistics" values.
> One of them is pretty steady at:
>   PCS statistics                      Seconds
>     Bit errors                             4
>     Errored blocks                         4
> The other one seems to vary with the values ranging from 10 to 70.
> EG:
>   PCS statistics                      Seconds
>     Bit errors                            61
>     Errored blocks                        69
> The second interface will will trigger a number of error conditions at the
> other end which terminates in a Cisco router with out showing any error
> conditions at my end (EG BPDU Error: None, MAC-REWRITE Error: None,
> CRC/Align errors 0, FIFO errors 0, etc..) During some of these times I'll
> see significant packet loss and others see minimal problems.
> According to Juniper docs the PCS statistics should mean:
>  PCS statistics
>   (10-Gigabit Ethernet interfaces) Displays Physical Coding Sublayer (PCS)
> fault
>   conditions from the WAN PHY or the LAN PHY device.
>     Bit errors—High bit error rate. Indicates the number of bit errors
> when the
>       PCS receiver is operating in normal mode.
>     Errored blocks—Loss of block lock. The number of errored blocks when
>       receiver is operating in normal mode.
> But I don't know how to interpret a value of "16 seconds" with that
> definition.
> Can anybody shed some light on what those numbers mean.
> Thanks.
> --
> Dave Funk                                  University of Iowa
> <dbfunk (at) engineering.uiowa.edu>        College of Engineering
> 319/335-5751   FAX: 319/384-0549           1256 Seamans Center
> Sys_admin/Postmaster/cell_admin            Iowa City, IA 52242-1527
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*Michael Carey*
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