Expand Configuration and Management Manual (H06.21+, J06.10+)

Subsystem Description
Expand Configuration and Management Manual — 529522-013
17 - 3
Expand Line-Handler Processes
A multi-CPU path is created by associating Expand line-handler processes with one
another using the SUPERPATH_ON modifier. Each line-handler process that is a
member of a multi-CPU path is configured in a different processor.
Expand Line-Handler Process Types
Expand line-handler processes can be categorized as:
•
Those that contain all the protocol levels necessary to perform both path and line
functions. These types of Expand line-handler processes include:
°
Direct-connect
°
Satellite-connect
•
Those that require another type of process to perform line functions. These types
of Expand line-handler processes include:
°
Expand-over-NAM
°
Expand-over-IP
°
Expand-over-ServerNet
°
Expand-over-ATM
The different types of Expand line-handler processes are described in these
subsections. For more information on how to configure Expand line-handler processes,
see Section 5, Configuration Overview.
Direct-Connect and Satellite-Connect Expand Line-Handler
Processes
The direct-connect line-handler process implements the High-Level Data Link Control
(HDLC) Normal protocol. This type of Expand line-handler process is provided for use
with conventional voice-grade leased-line and switched-line facilities, private facilities,
and fractional Transmission Group 1 (T1) facilities.
The satellite-connect line-handler process implement
s the satellite-efficient version of
the HDLC protocol, the HDLC Extended Mode protocol. Unlike the HDLC Normal
protocol implemented by direct-connect Expand line-handler processes, the HDLC
Extended Mode protocol uses the maximum window size of 61 frames (the maximum
number of outstanding frames before an acknowledgment is required) and implements
the selective reject feature. Selective reject causes only frames that arrive in error to
be retransmitted.
Although the satellite-connect line-handler process is provided for use with satellite
connections, it can also be used to manage terrestrial lines. This type of configuration
can enhance the reliability of terrestrial lines that carry small messages at high speeds.
Note. The path and line functions of an Expand line-handler process are described in more
detail in
Expand Subsystem and the OSI Reference Model on page 17-9.