Ascend Archive
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Re: (ASCEND) Max 1800 - CallType = Nailed/MPP

Hi,

On Wed, Mar 11, 1998 at 08:38:16PM +0900, Peter Chow wrote:
> We have a Max 1800 used for leased lines.  I would like to
> use MP to load share across 2 leased lines to my Cisco 2501.

I'm pretty sure with the current (partially broken) leased line
support of the Max family you won't get this running. But I'm glad
to hear it works, so if...

> I checked my Max manual and under the Configuring the WAN
> section - Setting parameters for an MP+ link using multiple
> nailed-up channels, it says I need to configure the connection
> profile...Telco...Call Type = Nailed/MPP. 

Yes. This is a mixup of two different things Ascend has kludged together
for some strange reason. They have a line operation mode "Nailed/Mpp"
which is useful to dynamically add and remove dialed bandwidth to a
leased line. The sense of "Nailed/Mpp" is to be able to specify a
Dial # and whenever the DBA thinks it would be necessary, the Max dials
this number (according to normal MPP procedures) in order to add bandwidth
dynamically. This is for sure a great idea. The bad thing is, "Nailed/Mpp"
is the _only_ mode where you can specify more than one Group# in the
connection profile. This is nonsense, because you must be able to specify
multiple groups ASA you have either MP or MPP selected as the connection
encapsulation. In most cases you _dont_ want to combine bundled leased
lines with dial DBA, so it is broken to make this only available with
"Nailed/Mpp", "Nailed" must suffice.

> I checked the Max 1800 (5.0Ap38) and it only has Nailed/Switched
> and Perm/Switched. 

You probably have selected PPP encapsulation. You must select MPP for
Nailed/Mpp to appear. But beware: This will likely not work as expected
against a Cisco. I would be glad to hear otherwise, but I don't believe.
And even if it works, I _must_ be able to say Encaps=MP/Nailed/Group=1,2
else something is not thought to the end.

> Can the Max 1800 do Nailed/MPP?  Would "Nailed" work as well?

It can, with the limitations above. Nailed may give you another option,
see below.

> I was planning to configure the Net/BRI Prt/Grp parameter for
> all the leased lines to be in the same group.  And then in 
> the connection profile set the Telco...Group to that Prt/Grp
> value.

This is the wrong way for what you want. If you give the same Group#
to several lines, the Max does low level bundling for them if at all
possible. You can bundle the 2B of a BRI, or any chunk of Bs of a PRI
this way, but this has limits (you cannot lowlevel bundle above multiple
physical interfaces without likely sync loss, and even within single
interfaces sync problems are to be expected with BRI [in Germany, the
telco routes D64S2 lines {2B BRI leased line} usually via E1 muxes,
which have plugtables with 16 channels each in two columns - they plug them
from left to right instead of top-down, giving B2 a half E1-frame time
delay, which is obviously a BRI half octett delay, causing octet sync
to be lost]) so you cannot use this feature that often. If you can use
it you simply use PPP and Nailed and it works almost flawless.

> Any one done this before?  I've found MP between leased lines
> for Cisco, but haven't found one between Cisco and Ascend.

There is a pletora of things that are glitchy with Ascends support
for leased lines. Bad enough it seems to be of minor priority to
Ascend to fix this (in some cases it is eventually a large change
in architecture that would first be necessary in order to fix some
glitches), because nothing has changed here for a long time. We are
using leased lines with Ascend boxes and I'm getting closer to the
point where I beg my boss for a Cisco 7200 or such. Instabilities in
newer firmwares make it impossible for us to use anything beyond 5.0Ap13
and I'm close to the conclusion that it is our extensive use of leased
line hacks with the Max that makes it that instable.

If you're interested in a (even) longer pamphlet on the whole topic
from my keyboard, go to this lists archive and search for a posting
with subject "The Nailing Game". It's getting boring to write this
stuff again and again :-/

-- 

Kanther-Line: PGP SSH IDEA MD5 GOST RIPE-MD160 3DES RSA FEAL32 RC4

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