[j-nsp] Traffic shaping on J and SRX

[Dale Shaw]

Hi all,

I need to shape on egress from CE to PE to match the service
provider's 'PVC' speed. The physical interface is gigabit Ethernet. We
have a variety of J and SRX boxes running JUNOS 10.0R3.

We have the following access/service speed combos (all on J/SRX
ge-x/x/x or SRX xe-x/x/x): 100m/10m, 1g/50m, 1g/100m, 1g/150m,
1g/200m, 10g/1g.

I have a JTAC case running on this but I haven't been making good progress.

The carrier's EoSDH access network throws away traffic when bursts
fill up the relatively small buffers (~130K) in their Alcatel
equipment. I need to tune the shaper to control/buffer bursts.

Through the JTAC case (which I have just asked to be escalated), I
have NOT been able to determine:

1. how the burst size is calculated when (for example) 'shaping-rate
150m' is used without any other configuration on a logical unit.
2. how, if at all, the burst size can be tuned. I need to ensure I
drive the burst size (in bytes) down to <=130K for all of the
access/speed combinations above

How is everyone doing this in the real world?

Lastly, through my investigations with Juniper folks outside the JTAC,
I have become aware of two things:

- The default burst size on J-series cannot be configured and
(whatever it is,) is too high
- PR/511498. "The shaper burst-size was calculated based on
interface-bandwidth instead of the shaping-rate". Fixed in
10.0-20100326.0 daily SR or later, apparently. No more info.

I hate to draw the comparison but detailed information about how the
shaper works and can be tuned is readily available in vendor C land
:-/

Cheers,
Dale