[c-nsp] DS3 problem on PA-T3

[Jay Nakamura]

Just an update, I installed 10db attenuator and errors have gone away.
Thank you all for the suggestion!

On Wed, Oct 1, 2008 at 7:54 PM, Robert Boyle <robert at tellurian.com> wrote:

> At 11:56 AM 10/1/2008, Jay Nakamura wrote:
>
>> It looks like Opti-3 have "Long" and "Short" option for LBO on the DS3
>> interface.  I am going to make sure Verizon set it to short since the coax
>> is only about 15' long.
>>
>
> Even with short LBO, we still need the attenuators sometimes. Look for LCV
> errors.
>
>  I don't have any attenuators handy to try that out.  I did however,
>> changed
>> the DSU mode to Kentrox and errors have gone away for the last hour.  I
>> didn't think that really mattered if you were doing full DS3.
>>
>
> It does matter. Verizon does have a lot of ADC/Kentrox DSUs connecting via
> HSSI to their old frame relay switches in their COs. Be careful of a nasty
> bug we found which will hang the router on boot if all of the following are
> true:
>
> 1. You have a PA-T3 or PA-2T3
> 2. You have dsu mode 2? (Kentrox mode whatever that is - I don't have time
> to look at the config at the moment)
> 3. A T3 is connected (unplug the T3 RECV and it will boot fine)
> 4. You reboot (soft or hard)
>
> The router will hang right after it lists the RAM during the POST. The
> problem is with the microcode initialization for the DS3 chip when using
> Kentrox mode and only if there is carrier detected. They finally fixed this,
> but it is late in the 12.3 train and I don't think they backported it to
> 12.2. This is a nasty surprise when you reboot the router at a remote POP at
> 3AM. Just test for this and if you have the bug, let me know and I'll track
> down the bug ID in my archives. This problem was reproducible on any 72XX
> router with any PA-T3 or PA-2T3(+) card.
>
> -Robert
>
>
>
>
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