FW 05.01.00 and SW 07.01.00 HP StorageWorks Directors and Edge Switches Glossary (AA-RU5JA-TE, June 2003)

Glossary
5Directors and Edge Switches Glossary
backplane
The backplane provides 48 VDC power distribution and connections for all logic cards.
backup FRU
When an active field-replaceable unit (FRU) fails, an identical backup FRU takes over operation
automatically (failover) to maintain director and Fibre Channel link operation. See also active
FRU.
BB_Credit
See buffer-to-buffer credit.
beaconing
Use of light-emitting diodes on ports, port cards, field-replaceable units, and directors to aid in
the fault-isolation process. When enabled, active beaconing causes LEDs to flash for selected
components.
BER
See bit error rate.
bezel
A removable panel that covers empty drive bays and port cards.
bidirectional
In Fibre Channel, the capability to simultaneously communicate at maximum speeds
(100 Mbps) in both directions over a link.
bit error rate
(BER) — Ratio of received bits that contain errors to total of all bits transmitted.
blocked connection
In S/390 mode, in a director or switch, the attribute that, when set, removes the communication
capability of a specific port. A blocked address is disabled so that no other address can be
connected to it. A blocked attribute supersedes a dedicated or prohibited attribute on the same
address. See also allowed connection, unblocked connection, connectivity attribute, dynamic
connection, and dynamic connectivity.
blocked port
Devices communicating with the port are prevented from logging into the director or
communicating with other devices attached to the director. A blocked port continuously
transmits the offline sequence.
bridge
Device that connects and passes packets between two network segments that use the same
communications protocol.