Installing and Administering OSI Transport Services

Chapter 3 89
Gathering Configuration Information
Using the Remote System Worksheet
Network Addresses (NSAPs)
The last items you should provide are the Network Addresses
(sometimes referred to as NSAPs) that are used to access this system.
The full NSAP should be specified here if the remote configures the
Network Address in components (IDP, DSP), or does not include the
NSEL. These values should all be concatenated and written in the
appropriate field.
RFC1006 NSAP and IP Address
OSI uses NSAP network addresses. TCP/IP uses IP addresses. Since the
OSI networking layer is replaced by TCP/IP, the special RFC1006 NSAP
must be used in any OSI dialog between systems.
The RFC1006 NSAP has:
• a specific header with an IP address, for example, RFC1006 NSAP is
540072872203
• optionally a TCP port ID appended to it
Therefore, an OSI service running over TCP must specify a destination
NSAP using the RFC1006 NSAP structure.
The IP address of 123.55.77.5 is encoded in the RFC1006 NSAP as a
string of digits using three digits corresponding to one octet of the IP
address.
If the default port (102) is not used, the TCP port number is encoded as 5
digits followed by “F”.
The complete RFC1006 NSAP with an optional port number of 103 is
shown below. If you use the standard port of 102 you omit the port
number from the end of the NSAP.
IP Address of: Encoded in NSAP as:
123.55.77.5 123055077005