We're still having trouble getting MPPP connections to work. When the
second channel connects it clobbers the entire session the majority of
the time.
At first I thought this was just a multi-chassis issue, but that doesn't
seem to be part of the equation any more. Our testers are as unlikely to
get a dual channel connection to a single PM3 as they are when they hit
two different units.
I opened a ticket with Livingston but nothing has come of it. They tried
connecting themselves (3 times) and had no problems, so they say it's
probably the customer's configuration.
Then we found this page at Microsoft:
http://premium.microsoft.com/support/kb/articles/q169/1/36.asp
In it they describe the exact problem and lay the blame squarely on the
PortMaster. Here's a quote:
This is caused by a limitation in certain versions of the firmware on the
Livingston Portmaster, which do not allow simultaneous connections within
500 milliseconds of one another.
The reason Windows 95 clients can connect to the Livingston Portmaster and
Windows NT clients fail is because Windows NT 4.0 tries to connect both
channels simultaneously. Windows 95 establishes the connection on the first
channel then dials the second channel.
They go on to reccomend a ComOS upgrade to the latest version. Of course
we already have the latest version installed...
However, our initial testers were using Macs and/or Windows NT. We now have
a couple folks using Windows '95 and so far they have indicated no problems.
This seems to support Microsoft's statements. They are all using different
brands of ISDN TAs (3Com, Motorola, Adtran, etc).
Furthermore, a Mac user has found that if he ties up the second channel
manually with a handset, the first channel connects fine. When he hangs
up the handset the second channel connects and he gets 128K and all is
well.
So, is there a known MPPP timing problem? If so, is there a work-around
and will it be fixed in the next ComOS?
Mark
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