IBM SAN32M1, Инструкция по установке и обслуживанию

Страница: 565 / 626

533 Glossary
between two network segments that use the same communications
protocol.
bridge port B_Port. (1) In Fibre Channel protocol, a fabric inter-element port used
to connect bridge devices with E_Ports on a switch. B_Ports provide a
subset of E_Port functionality. (2) A IBM term for a physical interface
between the fabric (switch) and a bridge device. The interface is iden-
tical to an expansion port (E_Port), but it does not participate in full
expansion port protocols. As such, it does not assign domain IDs or
participate in routing protocol. See also
expansion port ; fabric port ;
generic port ; node port ; segmented expansion port .
British thermal unit Btu. The quantity of heat required to raise the temperature of one
pound of water by one degree Fahrenheit (D).
broadband Large bandwidth communications channel capable of multiple, par-
allel high-speed transmissions.
broadcast In Fibre Channel protocol, to send a transmission to all node ports
(N_Ports) on a fabric. See also
broadcast frame .
broadcast frame In Fibre Channel protocol, a frame whose destination address speci-
fies all node ports (N_Ports) in the fabric. See also
broadcast .
Btu See British thermal unit .
buffer Storage area for data in transit. Buffers compensate for differences in
processing speeds between devices. See
buffer-to-buffer credit .
buffer-to-buffer credit BB_Credit. (1) The maximum number of receive buffers allocated to a
transmitting node port (N_Port) or fabric port (F_Port). Credit repre-
sents the maximum number of outstanding frames that can be trans-
mitted by that N_Port or F_Port without causing a buffer overrun
condition at the receiver. (2) The maximum number of frames a port
can transmit without receiving a receive ready signal from the receiv-
ing device. BB_Credit can be adjustable to provide different levels of
compensation.
bypassed port
If a port is bypassed, all serial channel signals route past the port. A
device attached to the port cannot communicate with other devices in
the loop.