D-6
Cisco ONS 15454 Installation and Operations Guide
November 2001
AppendixD Glossary
G
GBIC
Gigabit Interface Converter. A hot-swappable input/output device that plugs into a Gigabit Ethern et port
to link the port with the fiber optic network.
H
Hard reset
The physical removal and insertion of a card. A card pu l l.
HDLC
High-Level Data Link Control. Bit-oriented, synchronous, data-link layer protocol develop ed by ISO.
HDLC specifies a data encapsulation method on synchronous serial links using frame characters and
checksums.
Host number
Part of IP address used to address an individual host within the network or subnetwork.
Hot swap
The process of replacing a failed component while the rest of the system continues to function normally.
I
Input alarms
Used for external sensors such as open doors, temperature sensors, flood sensors, and other
environmental conditions.
IP
Internet Protocol. Network layer protocol in the TCP/IP stack offering a connectionless internetwork
service. IP provides features for addressing, type-of-serv ice sp eci fic ation , fra gme ntat ion and
reassembly, and security.
IP address
32-bit address assigned to host using TCP/IP. An IP address belongs to one of five classes (A, B, C, D,
or E) and is written as 4 octets separated by periods (dotted decimal format). Each address consist s of a
network number, an optional subnetwork number, and a host number.
K
K bytes
Automatic protection switching bytes. K bytes are located in the SONET line overhead and monitored
by equipment for an indication to switch to protection.