DIVA T/A ISDN Modem User’s Guide ◆ Page 39
The DIVA Terminal Adapters Program for Windows95/98/NT
MultiLink PPP When you activate Multilink PPP, the DIVAT/A combines both ISDN B-channels into a
single 128 kbps communications link. Both channels remain in use as long as long as
the connection is active, which may result in excessive ISDN connection charges if
the link is frequently idle.
Multilink PPP reserves both ISDN B-channels for its exclusive use. If you use Multilink
PPP, you will not be able to make or receive other data calls.
Analog calls are governed by a different set of rules. By default, the DIVAT/A is
configured to support call bumping, which causes the DIVAT/A to drop one ISDN
channel when you make or receive an analog call.
This reduces the throughput of the data call to 64 kbps. When the analog call is
done, Multilink PPP re-establishes the second channel, returning the data
connection to 128 kbps.
Only one of the two PHONE ports can be used when a Multilink PPP connection is
active.
MultiLink PPP
with BACP
To save on communications charges, use Bandwidth Allocation Control Protocol
(BACP) in combination with Multilink PPP. The DIVAT/A uses BACP to monitor
incoming and outgoing traffic.
As traffic volume warrants, a second ISDN channel is opened or closed. This reduces
your communications charges by ensuring that two ISDN channels are never active
when one is sufficient.
As with MultiLink PPP, this setting reserves both ISDN B-channels for its exclusive use.
This means that if your Internet connection uses ‘MultiLink PPP withBACP ’, you will
not be able to make or receive other data calls.
As with MultiLink PPP, if both B-channels are active, call bumping forces the DIVAT/A
to drop one ISDN channel when you make or receive an analog call.
Only one phone port can be used when a ‘MultiLink PPP withBACP’ connection is
active. However, since ‘MultiLink PPP withBACP’ may only be using one ISDN
channel, either Phone1 or Phone 2 may not be available.
For example, if Phone 2 was in use when the data connection was established, the
data connection uses telephone number 1. Even though telephone number 2
becomes available when Phone2 hangs up, the data connection does not switch
over. If you try to use Phone1, you will get a busy signal.
MultiLink PPP
with AO/DI
Always On/Dynamic ISDN (AO/DI) uses the ISDN D-channel to maintain a permanent
connection to your ISP or corporate network. The D-channel connection operates at
16 kbps using the X.25 protocol. However, only 8-9 kbps is available for data transfer,
but it can be used to send and receive low-bandwidth data such as email.
AO/DI incorporates BACP, and uses it to monitor incoming and outgoing traffic.
When traffic volume warrants, it enables one or two ISDN B-channels to meet
demand. As with MultiLink PPP, this setting reserves both ISDN B-channels for its
exclusive use. If your Internet connection uses ‘MultiLink PPP withAO/DI’, you will
not be able to make or receive other data calls.
When using ‘MultiLink PPP with AO/DI’, both B-channels can be dropped, allowing
you to make or receive two analog calls. Since the data connection is still active on
the D-channel, you can use both phone ports at any time. However the speed of the
D-channel (16kbps) is much slower than a B-channel (64 kbps).
Setting Description