Installing and Administering OSI Transport Services

58 Chapter 1
HP OTS/9000 Resources
Current NSAP Allocation Formats
The Subnetwork Identifier may identify a physical subnetwork, or an
area. The Subnetwork Address field may contain a real subnetwork
address, such as a MAC or X.121 address, or a virtual end system
identifier that uniquely identifies the end system for the specified Subnet
ID. HP recommends that the NSel field be set to 01.
A more complete discussion of this addressing format may be found in
U.K. Government OSI Profile Specification Version 3.1 and Procedure for
Obtaining a U.K. Government Domain Part (GDP) under the ISO DCC
Addressing Scheme.
These documents are produced by the Central Computer and
Telecommunications Agency, UK. They should be available through
Omnicom International, Ltd. or CCTA.
GOSIP Project Office CCTA Riverwalk House 157/161 Millbank
LONDON SW1P 4RT UK
MAP/TOP 3.0
Figure 1-17
Subnetwork
IDP
DSP
9 octets
Station
Enterprise ID
NSel
ID
ID
Enterprise ID The AP portion of the NSAP. It includes the AFI, IDI
and, if necessary, an Org ID.
Subnetwork
ID
A portion that uniquely identifies the Subnetwork
on the Enterprise.
Station ID A portion that uniquely identifies an end system on
the subnetwork
NSel The field that identifies the entity above the network
layer.