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Chapter 1. APPN
This chapter describes APPN and includes the following sections:
v “What is APPN?”
v “What APPN Functions Are Implemented on the Router?” on page 3
v “APPN Network Node Optional Features” on page 6
v “Supported DLCs” on page 25
v “Router Configuration Process” on page 25
v “APPN Configuration Notes” on page 49
What is APPN?
Advanced Peer-to-Peer networking (APPN) extends the SNA architecture by
enabling Type 2.1 (T2.1) nodes to communicate directly without requiring the
services of a SNA host computer.
Peer-to-Peer Communications
T2.1 nodes can activate connections with other T2.1 nodes and establish LU-LU
sessions with other nodes. The relationship between a pair of T2.1 nodes is
referred to as a
peer relationship
because either side can initiate communication.
Prior to APPN, a T2.1 node could communicate directly with another T2.1 node, but
required the services of a centralized SNA host to locate its partner and any
associated resources. All routes between the two nodes were predefined. APPN
enhanced the T2.1 node function by:
v Requiring network resources to be defined only at the node where they are
located
v Distributing information about these resources throughout the network as needed
v Dynamically generating routes between nodes using current information about
the network’s topology and the desired class of service
APPN Node Types
The APPN architecture allows four types of nodes in a network:
v APPN network nodes
v APPN end nodes
v Low-entry networking (LEN) end nodes
v PU 2.0 nodes supported by DLUR
The router can be configured as an APPN network node that supports connections
with all four node types. The router cannot function as an end node for APPN.
APPN Network Node
An APPN network node provides directory and routing services for all resources
(LUs) in its domain. A network node’s domain consists of:
v Local resources owned by the node
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