Introduction to Networking for NonStop S-Series Servers

Introduction to Networking for HP NonStop S-Series Servers—520670-005
8-1
8
Open Systems Interconnection (OSI)
Network Connections
This section describes HP products that implement the standards of the Open Systems
Interconnection (OSI) architecture, including the International Telecommunications
Union–Telecommunications (ITU–T) Recommendation for packet-switched data
networks (PSDNs). These products enable HP networks to integrate with systems and
devices of other vendors providing OSI, X.25, and TCP/IP implementations.
This section discusses the following topics:
•
A Brief Look at OSI on this page
•
HP NonStop OSI Advantages on page 8-6
•
File Transfer, Access, and Management (OSI/FTAM) on page 8-8
•
Message Handling System (OSI/MHS) on page 8-9
•
Upper Layer Interfaces (OSI/AS) on page 8-14
•
Transport Layer Interface (OSI/TS) on page 8-14
•
Network and Data Link Interfaces on page 8-15
•
OSI Subsystem Management on page 8-16
•
OSI Application Example on page 8-16
A Brief Look at OSI
Most of the complexity in networking computer systems is caused by the
incompatibility of hardware and software produced by different manufacturers. In 1977,
the International Organization for Standardization (ISO) and the International Telegraph
and Telephone Consultative Committee (CCITT) began collaborating on a set of
standards based on the Reference Model for Open Systems Interconnection, more
commonly known as the OSI Reference Model (see Figure 8-1). The OSI Reference
Model is an architecture that enables different vendors’ systems to communicate by
using a common set of protocols.
HP and other major computer vendors have adopted the OSI protocol standards as a
strategy for achieving interconnectivity of systems in multivendor environments. Many
large organizations have also adopted the OSI Reference Model, both for the range of
functions it provides and because of the long-term flexibility of standards-based
solutions.
Note. CCITT is now known as the International Telecommunications Union (ITU). The
standards for telecommunications are known as the International Telecommunications Union
–
Telecommunications (ITU–T) standards.