BS 7221:1989

National foreword
Committees responsible
Specification
0 Introduction
1 Scope and field of application
2 References
3 Definitions
4 Abbreviations
5 Network Layer concepts and terminology
6 Organization of the Network Layer
7 Application of the Network Layer Internal
    organization
8 Interconnection scenarios
Tables
1 Correspondence between real world objects and
    abstract elements
2 Summary of interconnection scenarios
Figures
1 "Direct" communication between end systems (without
    an intermediate system)
2 End systems communicating through an intermediate
    system
3 Interconnection of real subnetworks that include
    integral interworking unit functionality
4 Interconnection of real subnetworks by a separate
    interworking unit
5 Relationship between subnetwork service and data
    transmission service
6 Network Layer protocol rules
7 Provision of CO-NS or CL-NS over a single data-link
8 Provision of CO-NS or CL-NS over a single subnetwork
9 Interconnection of subnetworks utilizing a single NL
    protocol to provide the CO-NS or CL-NS over two CO-
    or CL- subnetworks
10 Provision of the CO-NS over two CO- subnetworks
    using hop-by-hop harmonization
11 Provision of the CO-NS over two CL- subnetworks
    using an internetworking protocol approach
12 Provision of the CL-NS over two CL- subnetworks
    using hop-by-hop harmonization
13 Provision of the CL-NS over two CL- subnetworks
    using an internetworking protocol approach
14 Provision of the CL-NS over two CO- subnetworks
    using hop-by-hop harmonization
15 Provision of the CL-NS over two CO- subnetworks
    using an internetworking protocol approach
16 Provision of the CO-NS over two CL- subnetworks
    using hop-by-hop harmonization
17 Provision of the CO-NS over two CL- subnetworks
    using an internetworking protocol approach
18 Provision of the CL-NS over a CL- subnetwork and a
    CO- subnetwork using hop-by-hop harmonization
19 Provision of the CL-NS over a CL- subnetwork and a
    CO- subnetwork using an internetworking protocol
    approach
20 Provision of the CO-NS over a CL- subnetwork and a
    CO- subnetwork using hop-by-hop harmonization
21 Provision of the CO-NS over a CL- subnetwork and a
    CO- subnetwork using an internetworking protocol
    approach