APPN Concepts

Objectives
On successful completion of this course, attendees will be able to:

• identify the different APPN node types and state their purpose
• explain how resources are located and sessions started
• describe the structure of the distributed database
• describe the database search process
• interpret APPN message formats
• describe the structure of Class Of Service table entries
• describe how APPN dynamic routes are calculated
• identify typical Class Of Service table implementations
• explain how Intermediate Session Routing operates
• describe how High Performance Routing operates
• interpret the APPN/HPR message formats
• explain what path switching is and how it operates
• describe the adaptive rate based flow control mechanism
• describe how APPN and APPN/HPR can be integrated.

Who Should Attend
The course will benefit all levels of network technician working with an APPN network. Network systems programmers, administrators, operators, planners, and managers will all benefit from this course.
Prerequisites
Some knowledge of traditional 'subarea' SNA would be an advantage.
Duration
1 day
Course Code
ZB
Contents
Introduction and terminology
SNA subarea networks; SNA APPN networks; APPN: node types, contents; network & NAU names; APPN addresses; dependent & independent LUs; peripheral & extended border nodes; session services extensions; dependent LU server/requester; option sets.


Basic operation
Node control point; simple APPN networks; link activation; XID format 3; CP-CP session activation; conversations and GDS variables; resource location; LU-LU session activation; complex APPN networks; node capability exchanges; resource location; SPF directed graph; central directory server.


The distributed database
Database structure and domains; end node entries; network node entries; Wildcard entries; resource registration; types of search; search GDS variables; database search logic.


Class Of Service and route calculation
Topology and routing services; COS; transmission group and node characteristics; COS definition format and weight arrays; default COS and APPC mode names; sample COS definitions for VTAM, AS/400.


Intermediate Session Routing
Network node contents; intermediate session routing (ISR) function; ISR components; route selection; Local Form Session ID assignment; Bind extension and reduction; Bind RU and pacing modifications; PIU segmentation and reassembly; session routing; detecting node congestion.


High Performance Routing
ISR problems; increasing link reliability issues; high performance routing (HPR) components; HPR and SNA; HPR message formats; Automatic Network Routing (ANR) routing labels; ANR route setup; ANR operation; network layer header used by ANR; Rapid Transport Protocol (RTP) features; Transport layer header used by RTP; RTP connection setup; RTP acknowledgements; RTP selective retransmission; RTP segmentation; RTP adaptive rate based (ARB) flow control; ARM delay and send rate thresholds; RTP path switching operation; RTP path switching triggers; HPR option sets; HPR boundary function.