Technical data

Brocade SilkWorm 4100 Hardware Reference Manual Glossary-21
Publication Number: 53-0000563-02
ON Offline notification. Refers to an ELS field that appears in portlogdump command output.
OPN Open primitive signal. Applies only to arbitrated loop; sent by an L_Port that has won the arbitration
process to open communication with one or more ports on the loop.
ordered set A transmission word that uses 8b/10b mapping and begins with the K28.5 character. Ordered sets occur
outside of frames and include the following items:
Frame delimiters. Mark frame boundaries and describe frame contents.
Primitive signals. Indicate events.
Primitive sequences. Indicate or initiate port states.
Ordered sets are used to differentiate Fibre Channel control information from data frames and to
manage frame transport.
originator The Nx_Port that originated an exchange.
out-of-band Transmission of management protocol outside of the Fibre Channel network, usually over Ethernet.
oversub-
scription
A situation in which more nodes could potentially contend for a resource than the resource could
simultaneously support (typically an ISL). Oversubscription could be a desirable attribute in fabric
topology, as long as it does not produce unacceptable levels of congestion.
OX_ID Originator ID or exchange ID. Refers to the exchange ID assigned by the originator port.
P
packet A set of information transmitted across a network. See also frame.
PAL Programmable Array Logic. A relatively small FPD.
parallel The simultaneous transmission of data bits over multiple lines.
Participating
Mode
A mode in which an L_Port in a loop has a valid AL_PA and can arbitrate, send frames, and retransmit
received transmissions. See also L_Port, Nonparticipating Mode.
passive
copper
A low-cost copper Fibre Channel connection, allowing distances up to 13 meters between devices.
path selection The selection of a transmission path through the fabric. Brocade switches use the FSPF protocol. See
also FSPF.
payload A Fibre Channel frame has a header and a payload. The payload contains the information being
transported by the frame; it is determined by the higher-level service or FC_4 upper-level protocol.
There are many different payload formats, based on protocol.
PBC Port bypass circuit. A circuit in hubs or a disk enclosure to open or close a loop to add or remove nodes.
PCBA Printed circuit board assembly.
PCM Pulse-code modulation. A standard method of encoding analog audio signals in digital form.