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Re: (ASCEND) Analog Multilink PPP and RAS


This thread has wandered, so I hope we can split it in two.

When I said "I'm not aware of any other....blah blah, etc. etc." I was
referring to PC based dialers [the title of the thread is "Analog Multilink
PPP and RAS" after all.  So let's divide this into two discussions:

1.  Asynch MPP [Specifically Windows based PC's dialing into an access
router/server with more than one modem]
2. All other MP/MPP types [UNIX machines, ISDN TA's/routers, router to
router, etc. etc. etc.]

Sound fair?

Now, as to #1.  Microsoft release multiline RAS in NT 4.0 [there's a patch
for Win 95 as well, part of the ISDN connectivity kit].  Choosing "multiple
lines" in the "modem properties" dialog in RAS [dial up networking] allows
you to use two modems to dial into a RAS server.

The AMPP specs don't care about what kind of modems, serial ports, etc.
etc. that you have, but let's think it through for a minute.  The hardest
job an MP server has is to synch up the incoming calls.  This is easy in
the digital world, but in the analog world, it gets quite tricky.  Ascend
has had support for Analog MP in the MAX for awhile, but the only clients
that could do it were UNIX machines and some remote access servers.  When
Microsoft came out with its offering, it didn't work with the Max.
Basically there was too much slop on the client side of things and the Max
couldn't compensate [a Pentium box running NT4.0 is still not a REAL
workstation...].  Since this was a new offering from Microsoft, the
reworking of MP code in the Max to make it more aggressive [and lenient at
the same time...] in synching up the calls was put in an "i" release so it
could get beat up in the real world before going prime-time.

As to the client side, the closer in functionality the serial ports and the
modems are, the better it works.   The phone lines are not as important.
I've tested this with one "normal" POTS line and one going through a POTS
jack on a P25.  On the line going through the P25, I would get 33.6k and on
the POTS line I would get 31.2k and the lines synched up just fine.  The
key was that I used a third party 115k serial board [as Com2 and 3] and two
Courier V.Everything modems [same firmware, etc.].  Any attempts to get a
session with two different modems or different serial ports failed.

Reports from the field have been positive so far, both in the support for
Multiline RAS and that other aspects of MP didn't break, so we'll probably
see this in 5.1xxxx.

Anyway, I hope that clears that up...





cclemmer@baynetworks.com on 05/23/97 11:35:46 AM

To:   matt@ascend.com
cc:   Ascend-users@bungi.com (bcc: Jeff Powell/Ascend/US)
Subject:  Re: (ASCEND) Analog Multilink PPP and RAS





Matt,
What you describe is what I understood MP to be. The question that comes up
because of this then, is why would Livingston and maybe Ascend not support
MP over all types of links?
I keep seeing mixed responses as to whether the Ascend box does support MP
over any kind of link, while I saw a response from a Livingston guy who
indicated that their box only supports MP on ISDN calls.
Knowing that MP should not be related to the physical call type, why would
this limitation exist?
Can we get a definitive answer from Ascend as to whether or not the Ascend
boxes share this limitation? Again, I would expect that it is supported,
for the reasons you mentioned.
Charlie Clemmer
At 08:41 AM 5/23/97 -0700, Matt Holdrege wrote:
>Folks, MP operates at a layer above the physical connection or media. You
>can combine any types of calls in any increment. I've seen NT call the Max
>with one analog call bundled with one ISDN call. Or two analog calls
>together. I've seen the Max call a Bay router with 23 channels of MP.
>
>All MP does is take (in one case) the endpoint discriminator and compare
it
>with any other call it has, be it analog or MP or whatever. If there is a
>match, it bundles the two calls together. I haven't tested it on the Max
>5.0ap branch, but by the reports here I might assume that the Max code
>didn't check ED on analog calls. But the reports say that it does in the i
>branch.
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