Hayes Microcomputer Products PC Card - Manual (Page 12)

DIVA T/A PC Card Reference Guide 12
What is BACP/BOD?
DIVA T/A supports the Bandwidth Allocation Control Protocol
(BACP) and Bandwidth on Demand (BOD). These two features
combine to allow the DIVA T/A to establish multilink sessions that
provide larger amounts of bandwidth than that offered over a single
dialup channel. Such multilink sessions are established according to
procedures defined in the Internet Engineering Task Force (IETF)
PPP Multilink specification (RFC 1717).
BACP/BOD works by informing the DIVA T/A which dial-in ports
are presently available for a multilink session. It allows the answering
location to reserve those ports for the calling party and provides the
calling party with the telephone numbers of those ports.
A bandwidth control protocol also allows a user at the calling location
to establish a multilink session by knowing only one telephone
number instead of all the numbers to be dialed for the full session.
With a bandwidth control protocol, the answering location provides
the calling location with a list of the remaining telephone numbers to
be used for the connection, and the additional channels are dialed by
the calling equipment transparently to the user. This effectively raises
a 64kbps connection into a 128 kbps connection.
BACP/BOD also controls whether the second line is required or not.
When bandwidth demand goes up, the second B-channel can
automatically be established, and conversely, when bandwidth
demand goes down, the second channel can be dropped. The primary
advantage, therefore, is a reduction of dial up charges; a second line is
only used (and hence paid for) when it is required.