[cisco-nas] isdn and voice dialin config

[James Sneeringer]

On Thu, Aug 19, 2004 at 01:31:29PM -0800, Mark Johnson wrote:
> At 02:13 PM 8/19/2004 -0500, James Sneeringer wrote:
> >    controller T1 2/0
> >     pri-group timeslots 1-24
> 
> You also need to configure (either globally or under the interfadce) an
> ISDN switch-type.

Oops, yes, I know I need that.  Thanks.

I've noticed there is a global "isdn switch-type" and a controller- 
specific "isdn switch-type" command.  In a case like ours where we will
only have one PRI, does it particularly matter which one we use?

> Since you say that the ISDN users are nailed up, and the modems users are
> occasional, I would suggest you use different dialers.  For the ISDN users
> you could use <dialer idle 0>, to effectively make the idle infinite.  You
> would also then have more granularity in configuring async users (who may
> not need/want MPPP) versus sync users.

Good idea, thanks.  I'll do that.

> >    ip local pool dialin-pool X.X.X.2 X.X.X.9
> 
> You would want, at most, 23 addresses available, possibly less given MPPP.

The pool is small because the dedicated ISDN users receive static IP
addresses via RADIUS, so they won't use addresses from the pool.  Will
this cause IOS problems?  I've used NASes in the past (older PortMasters
in particular) that balk at being given a pool smaller than the channel
count.

> Yes, although there's no reason that the config could not be placed
> directly under the PRI.

Do you mean directly under Serial2/0:23 (the D channel), or do you mean
configuring each Serial2/0:xx channel individually?

> Using dialer-rotary is mostly for convenience,
> in not having to configure multiple interfaces repetitively.  The
> Dialer interface does not really have anything to do with any particular
> call; it's more just a configuration repository for the physical 
> interface(s).

Okay.  A sort of template?  Setting "rotary-group 1" tells IOS "integrate
the config from Dialer1".

> >  * Data calls will appear on a Virtual-Access interface.
> 
> Only when MPPP is actually negotiated; and in that case, 2 serial B-channels
> will be included as members in the Virtual-Access bundle master (sh ppp 
> mult).

So in the (rare for us) non-multilink case, I will only see the user on
a Serial2/0:xx channel?

> >  * Voice calls will appear on an Async interface corresponding to the TTY
> >    they landed on.
> 
> Yes, assuming that MPPP is NOT negotiated (which is why you may want to
> have a separate dialer interface for the async users, without MPPP enabled).

Good point.  Some versions of Windows negotiate it even if they don't
actually use more than one channel.

Thank you very much for replying.  It appears I'm on the right track.

-James