Specifications

Glossary
GL-3
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Broadcast
Data packet that will be 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.
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.
Crosspoint
A set of physical or logical contacts that operate together to extend the speech and signal channels in a switching network.
CTAG
Correlation Tag. A unique identifier given to each input command by the TL1 operator. When the ONS 15454 system responds
to a specific command, it includes the command’s CTAG in the reply. This eliminates discrepancies about which response
corresponds to which command.
CTC
Cisco Transport Controller. A Java-based graphical user interface (GUI) that allows operations, administration, maintenenance,
and provisioning (OAM&P) of the ONS 15454 using an Internet browser.
CTM
Cisco Transport Manager. A Java-based network management tool used to support large networks of Cisco 15000-class
equipment.