Cisco 10000 Series Configuration Manual page 354

Glossary
G
Gigabit Ethernet. Ethernet running at a transmission speed of 1 billion bits per second.
Gigabit Ethernet
H
High Level Data Link Control. Bit-oriented synchronous data link layer protocol developed by ISO.
HDLC
Derived from SDLC, HDLC specifies a data encapsulation method on synchronous serial links using
frame characters and checksums.
See HDLC.
High Level Data Link
Control
I
Internet Operating System. See
IOS
Internet Protocol. Network layer protocol in the TCP/IP stack offering a connectionless internetwork
IP
service. IP provides features for addressing, type-of-service specification, fragmentation and
reassembly, and security. Defined in RFC 791.
K
Message sent by one network device to inform another network device that the virtual circuit between
Keepalive message
the two is still active.
L
Line Alarm Indication Signal. A SONET port status indicator that activates when an LAIS defect
LAIS
occurs and does not clear throughout the alarm integration period, which is typically 2.5 seconds. An
LAIS defect occurs when bits 6, 7, and 8 of the K2 byte are 111 for three consecutive frames. This
occurrence begins the alarm integration period. If this period elapses without the detection of three
consecutive frames in which K2 bits 6, 7, and 8 show any pattern other than 111, the LAIS indicator
activates. The LAIS indicator clears when an LAIS defect does not occur for a time interval equal to
the alarm deactivation period (typically 10 seconds).
Any I/O card that can be inserted in a modular chassis.
Line card
Cisco 10000 Series Router Line Card Configuration Guide
GL-4
Cisco IOS.
OL-8834-04