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Re: (ASCEND) MAX 1800 bri prob

> Could either of you give me some background on this problem? I'm curious to
> know whether it's the same problem that we've been seeing with our MAX 1800.
> Basically, our problem is that after the box has been running for a while, it
> starts getting really horrible throughput when there are several B channels
> connected (the problem would get bad around 6 or 7).
> 
> When it loses sync, does it cause this behavior of dropping packets? (A Ping
> to the P50/P75 units at the other end would show a packet loss of >25%.)

Actually this is not the problem we experienced (could be related?)

We experienced massive problems losing BRIs.

On a DMS-100 switch in NI-1 mode, our BRIs would sometimes go into the "M"
state instead of "D", where only one of the two channels works. It also
messes up the hunt group. Physically unplugging and replugging the line
may of may not help.

If you would cycle the line in software (set Enabled=No then Enabled=Yes)
or indeed if you made any change whatsoever on any of the BRIs, all the BRIs
would go down when you saved the change.

Some would come back in "." state (not working at all), others in the "M"
state. Only a lot of playing with the lines, enabling them and disabling
them over and over would help -- eventually you would get lucky and most or
all of them would come up "D".

Sometimes only repeatedly resetting the unit would help. Again, you'd be
gambling until you got lucky.

I firmly believe the problem is due to the fact that the MAX 1800 uses
the receive clock on one BRI as the transmit clock on all BRIs.

We hypothesize that it helps a lot to have all your lines plugged into the
same line card. Thing is, the telco usually tries to do the opposite (plug
no two of your lines into the same line card) in order to minimize damage
in case of line card failure.

One MAX 1800 in one of our POPs has been very lucky. It runs 5.0A. All lines
are up "D" and we're never, ever touching it again because it's been working
perfectly for 150 days straight (yes, it's our piece of quipment with the
highest uptime). But we couldn't keep the same MAX up for a day and a half
in its previous location in another city.

Maybe all its lines are on the same line card.

-Phil
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