Cisco ONS 15327 User Documentation page 527

Glossary
Blue band
Dense wavelength division multiplexing (DWDM) wavelengths are broken into two distinct bands: red and blue. DWDM cards
for the ONS 15454 operate on wavelengths between 1530.33nm and 1542.94nm in the blue band. The blue band is the lower
frequency band.
Bridge
Device that connects and passes packets between two network segments that use the same communications protocol. In general,
a bridge will filter, forward, or flood an incoming frame based on the MAC address of that frame.
Broadcast
Data packet that is sent to all nodes on a network. Broadcasts are identified by a broadcast address. Compare with multicast
and unicast. See also Broadcast address.
Broadcast address
Special address reserved for sending a message to all stations. Generally, a broadcast address is a MAC destination address of
all ones.
Broadcast storm
Undesirable network event in which many broadcasts are sent simultaneously across all network segments. A broadcast storm
uses substantial network bandwidth and, typically, causes network time-outs.
Bus
Common physical signal path composed of wires or other media across which signals can be sent from one part of a computer
to another.
C
C2 byte
The C2 byte is the signal label byte in the STS path overhead. This byte tells the equipment what the SONET payload envelope
contains and how it is constructed.
Cell
Basic Unit of ATM switching and multiplexing. Cells contain identifiers that specify the data stream where they belong.
CEV
Controlled environment vault. An underground room that houses electronic and/or optical equipment in controlled temperature
and humidity.
Collision
In Ethernet, the result of two nodes transmitting simultaneously. The frames from each device impact and are damaged when
they meet on the physical media.
Concatenation
A mechanism for allocating contiguous bandwidth for payload transport. Through the use of concatenation pointers, multiple
OC-1s can be linked together to provide contiguous bandwidth through the network, from end to end.
Cisco ONS 15327 User Documentation, R3.3
GL-3
June 2002