Glossary E-3
B8ZS (Bipolar with Eight Zero Suppression)
A T1 line protocol that converts a channel word with eight consecutive zeros into a code which,
at the far end, is converted back to eight zeros. Allows 64 Kbps clear channel operation while
assuring the ones density required on the T1 line.
bandwidth reservation
An IPX software feature that allows circuits to automatically become active (or “upped”) at a
specified time and date and downed at some later time and date. For circuits that do not need to
be available 100% of the time.
B channel
In ISDN, a full-duplex, 64-kbps channel used to send user data. Also known as the bearer
channel. Compare with D channel.
BCC
The control card for the BPX switch.
BC-E1 (Backcard E1)
E1 interface card used on IPX and IGX switches.
BC-E3 (Backcard E3)
E3 interface card used on IPX and IGX switches.
BC-J1 (Backcard J1)
J1 interface card used on IPX and IGX switches.
BC-SR (Backcard Subrate)
Subrate interface card used on IPX and IGX switches.
BC-T1 (Backcard T1)
T1 interface card used on IPX and IGX switches.
BC-T3 (Backcard T3)
T3 interface card used on IPX and IGX switches.
BC-Y1 (Backcard Y1)
Y1 interface card used on IPX and IGX switches.
BDA (Bframe Destination Address)
The address of the slot.port.channel for which the Bframe is destined. This address is part of the
Bframe header and is only used across the switch fabric locally in the node.
Bframe
The BPX frame is the 64-byte format for messages used to encapsulate ATM cells which are sent
across the switch fabric.
bipolar violations
Presence or absence of extra “1” bits on a T1 transmission facility caused by interference or a
failing line repeater. These extra or missing bits interrupts one of the rules for bipolar pairs of a
digital transmission line.
BISDN (broadband ISDN)
ITU-T communication standards designed to handle high-bandwidth applications. Compare with
ISDN.
