TS Supplement (Includes RFC-1006 Support)

Changes in the Transport Layer When Using RFC-1006

Introduction to RFC-1006

107751 Tandem Computers Incorporated 1–23

Parameter Mapping

Between OSI Network

Service and TCP

Table 1-7 lists the OSI network service primitives parameters and shows the

corresponding TCP service primitives parameters.

Table 1-7. Parameter Mapping

Connection Establishment

Network Service Parameter TCP Parameter

Called address Server's IP address (4 octets)

Calling address Client's IP address (4 octets)

All others Ignored

Data Transfer

Network Service Parameter TCP Parameter

NS user data (NSDU) Data

Connection Release

Network Service Parameter TCP Parameter

All Ignored

Transport Service

Procedures

This section contains information on transport service procedures performed by

OSI/TS when you are using RFC-1006.

Connection Establishment

The procedures used during connection establishment are identical to those presented

in ISO 8073, with two exceptions previously mentioned:

1. The CR and CC-TPDUs may exchange initial user data, using the user data fields

of these TPDUs.

2. The CR and CC-TPDUs may negotiate the use of transport expedited data (ED)

transfer service for OSI transport protocol class 0.

OSI/TS performs an N-CONNECT.REQUEST action, the transport service client

performs an ACTIVE open to the desired IP address using any port from 1024 and up

(ports 1 to 1023 are reserved for for servers, ports 1 to 255 are reserved for well-known

server ports). When the TCP signals either success or failure, this results in an N-

CONNECT.INDICATION event on the transport service server.

To await an N-CONNECT.INDICATION event, a transport service server listens

(performs a PASSIVE open) on TCP well-known port 102, which is reserved for RFC-

1006 (ISO-TSAP). When a client successfully connects to this port, the N-

CONNECTION.INDICATION event occurs, and an N-CONNECT.RESPONSE action