Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-10
Expand Line-Handler Process Layer Functions
Expand Line-Handler Process Layer Functions
An Expand line-handler process implements several different protocols, including the
HP proprietary End-to-End protocol. These protocols provide some of the functions
defined by the lower five layers of the OSI Reference Model.
OSI Session Layer (Layer 5)
The OSI Session Layer coordinates processes and is responsible for the setup and
termination of a communications path.
The following path functions of the End-to-End protocol correspond to some of the OSI
Session Layer functions:
•
System-to-system connection establishment and termination
•
Security processing (remote passwords, accessing Safeguard)
OSI Transport Layer (Layer 4)
The OSI Transport Layer accepts data from the OSI Session Layer and passes it to the
OSI Network Layer. The OSI Transport Layer provides end-to-end data integrity
between processes and verifies that messages received are correct.
The following path functions of the End-to-End protocol correspond to some of the OSI
Transport Layer functions:
•
Message management and buffering between processes (end-to-end). This
includes reassembling messages from incoming packets and multiplexing
outbound messages over available lines
•
Request/response matching
•
Flow control
•
Canceled-request handling
The Transport Layer, or path function, of the Expand line-handler process corresponds
to the Expand SCF PATH object.
OSI Network Layer (Layer 3)
The OSI Network Layer governs the switching and routing of information between
nodes in the network and is responsible for error-checking and recovery.
The following line functions of the End-to-End protocol correspond to some of the OSI
Network Layer functions:
•
Routing incoming passthrough traffic to another Expand line-handler process
•
Error-checking and recovery
The Network Layer, or path function, of the Expand line-handler process corresponds
to the Expand SCF PATH object.