Ascend Archive
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Re: (ASCEND) Max 4000 & P50



On Wed, Sep 24, 1997 at 04:32:27PM +0200, Joerg Bauer wrote:
> Andre Beck wrote:
> > 
> > On Tue, Sep 23, 1997 at 02:55:50PM -0700, Peter Tran wrote:
> > >
> > > Do the Max 4000 & the Pipeline P50 support 128 kb leased line?
> > 
> > Sort of. The problem is at the P50.
> > 
> > 1) The P50 has no Leased/Leased setting until now. Current status is that
> >    the feature may appear in Oct97. We need it strong, so we are quite
> >    on the edge here ;)
> >    This makes use of the obvious MPP bundling impossible.
> 
> We also need it !!!! I canīt see the problem why it isn#t possible. The
> feature works on all the MAX-boxes as far as i know.

It's even more confusing, as the P50 _can_ bundle in Switched/Switched
mode, so the probable guess that they may have a hardware limitation is
not true. If they can do it with dynamically assigned B-channels, they sure
could do it with statically assigned ones (actually this is a simpler case).

IMHO (subjectively ;) the problem they have is that they used a hack to
code "SuperDig128" in the NVRAM config. They code it as B1=Nailed Group=1
and B2=Nailed Group=2 (note that these codings are internal, you never
have a chance to touch them directly, you always select Switched/Unused
or such). Now it _should_ have been Group=1 for both channels. This collides
with the meaning I would actually underlay the Group=1,2 setting - the
meaning of Leased/Leased so you could either put separate profiles on
Group=1 and Group=2 or a Nailed/Mpp profile on Group=1,2 to get 128kbps
high level bundling. Then again, may be not.

> > 2) SuperDig128
> >    The P50 has SuperDig128, a very mystical feature that is "only available
> >    in Japan". Of cause this is Zen. Actually SuperDig128 seems to be a
> >    straight B1B2B1B2 low level bundling in the S0 frames. This makes it
> >    very easy to handle and performant but also very sensitive to any kind
> >    of asynchronity in the two B channels of such leased lines. Result:
> >    a) It works perfectly with our selfmade lines in lab
> >    b) It doesn't work with the lines provided by our telco (German Telekom).
> 
> I played around with this feature for some hours -----> no success

On -T-- lines you just get CRC errors because the channels are out of
sync. There are, however, reports where it did work. We guess in these
cases the -T-- used other tech or actually provided a DS02 no D64S2.
DS02 are guranteed to be octed synchronous, D64S2 are not.

> We hope that ascend will do it in October

We (and a bunch of our customers), too.

(BTW, for a history of this pletora, just grep this mail list archives
for "SuperDig128"...).

-- 

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| o |               \\\- Brain Inside -///                   | o |
| o |                   ^^^^^^^^^^^^^^                       | o |
| o | Andre' Beck (ABPSoft) beck@ibh-dd.de XLink PoP Dresden | o |
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