DS3 Troubles

[Daniel Smith]

We moved a DS3 from an IGX network to a pair of 7609s. Each end is equipped with a PA-T3, installed into an enhanced FlexWan. This connection has been very unreliable. The circuit itself ran fine on the IGX's, however, we have nothing but trouble on the 7600's. The configuration is pretty straightforward. We have changed the PA's with the same results. Any suggestions on how to trouble shoot this would be appreciated.

[zodell]

Is the circuit taking errors or does it just die. If you are having trouble with the circuit taking errors, have the telco put a hard loop on their DS3 jackfield or have them put a soft loop on their router and run to it. I assume that the cabling didn't change, but you might also recrimp the adapters.

[frennzy]

I did something similar a few years back. We had *terrible* problems, but only with certain emails or file formats not being transferred properly. It almost seemed as if the PA T3s were selectively hammering microsoft documents.

It turns out...it was.

The problem was two fold:

1. The LBO is different between an IGX and a PA-T3. Make sure you set this appropriately.

2. We had not setup encryption...and because MS documents have a *lot* of whitespace in them (extended runs of binary 0), the link thought it had entered a failure mode, and would drop the cell.

Fixing the LBO value and enabling encryption (which scrambles the whitespace) solved the problem.