Overview Of Isdn Connections - HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual

Configuring Demand Routing for Primary ISDN Modules

Overview of ISDN Connections

8-4
Overview of ISDN Connections
Integrated Services Digital Network (ISDN) connections are point-to-point
dial-up connections that can handle both voice and data over a single line.
ISDN provides WAN connections at a lower cost than dedicated WAN connec-
tions such as E1- or T1-carrier lines. Like telephone calls, ISDN connections
incur costs only when the connection is established.
To establish and maintain the connection through the public carrier network,
ISDN connections are divided into two types of channels:
bearer (B)
data (D)
B channels carry voice and data over the connection and transmit data at 56
or 64 Kbps. The D channel maintains the connection and transmits the
signaling and call-control information at 16 or 64 Kbps.
Two types of ISDN connections are available:
ISDN Basic Rate Interface (BRI)
ISDN Primary Rate Interface (PRI)
ISDN BRI provides two 64-Kbps B channels and one 16 Kbps D channel. If you
bond or multilink the two B channels in a ISDN BRI connection, the total
transmission rate is 128 Kbps. (Multilinking the two channels is discussed in
more detail later in this chapter.)
PRI ISDN, on the other hand, provides 23 B channels and 1 D channel in North
America and Japan and 30 B channels and 1 D channel in Europe, Asia (except
Japan), Australia, and South America. (When PRI includes 30 B channels,
channel 0 is used to maintain synchronization and is not counted as either a
B or D channel.) The transmission rates for PRI ISDN match the transmission
rates for an E1- or T1-carrier line. In North America and Japan, PRI ISDN
provides 1.544 Mbps. In other areas, PRI ISDN provides 2.048 Mbps.
In an ISDN connection, the B channels are treated independently. They can
be used for simultaneous voice and data; in other words, you can talk on the
phone and surf the Web at the same time. For example, if you have an ISDN
BRI connection, you can use both channels for data only, or you can use each
channel to connect to a different remote office.
The ProCurve Secure Router currently supports ISDN BRI connections.
Consequently, this chapter focuses on ISDN BRI.