[j-nsp] packet checksum error in input fab_stream

[Pavel Lunin]

+1 to Saku.

This means your egress PFE, identified by FPC <ID> and ICHIP(<ID>),
receives corrupted cells from the fabric. It might be caused by ingress PFE
or fabric chips or even backplane lines.

In this case you see it on different fabric streams, so it means that this
is not caused by a single faulty ingress PFE, otherwise you'd see the same
fab_stream IDs on the egress side (this is were the error is detected).
Stream 4 is from FPC1-PFE0, stream 7 is from FPC1-PFE3 and so on (STREAM_ID
= FPC_ID × 4 + PFE_ID).

Some strange thing here is PFE_ID 128. This should be a kind of dummy ID
(MX960 max PFE_ID is 47), I don't know what it means. Maybe some I-CHIP
specificity, e. g., as I remember, they looped packets, switched between
two interfaces on the same PFE, through the fabric as well. Might be
related to something like this or a cosmetic bug in the log.

Yes, j-cell corruption might be caused by elements, affected by
environmental conditions like high temperature.

If this happens frequently and you don't have a spare SCB, you might want
to play around with disable/enable fabric planes to isolate them one by one
and see if the error persists. This is disruptive and requires certain
level of understand of how all this works.

Take a look at KB20741.


2017-08-01 4:22 GMT+02:00 Joerg Staedele <js at tnib.de>:

> Hi Guys,
>
> i get several messages like:
>
> Aug  1 03:34:13 xxx fpc0 ICHIP(3)_REG_ERR:packet checksum error in input
> fab_stream 4 pfe_id 128
> Aug  1 03:34:19 xxx fpc2 ICHIP(0)_REG_ERR:packet checksum error in input
> fab_stream 7 pfe_id 128
> Aug  1 03:36:24 xxx fpc7 ICHIP(3)_REG_ERR:packet checksum error in input
> fab_stream 6 pfe_id 128
> Aug  1 03:36:24 xxx fpc7 ICHIP(3)_REG_ERR:packet checksum error in input
> fab_stream 17 pfe_id 128
>
> JunOS 14.1R8 on MX960 (with dual RE-2000)
>
> It does not seem to have any effect.
>
> Anyone knows what exactly it means?
>
> Kind regards
>  Joerg
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