OSI/TS Configuration and Management Manual

Background Information About Addressing
OSI/TS Configuration and Management Manual—424831-001
2-7
Structure of NSAP Addresses
Outgoing Call Request Packets
For outgoing call request packets, X25AM inserts called and calling address extensions
if the subdevice is configured with local/remote address extension.
Incoming Call Request Packets
If an incoming call request packet contains a 1980-format called address, X25AM
selects only subdevices with 1980-format local address configured, using the port
number.
If an incoming call request packet contains a 1984-format called address, X25AM
selects only subdevices with 1984-format local address configured. The call is routed to
a subdevice if the called address extension matches the subdevice local address
extension value. The port number is ignored.
The calling address extension in an incoming packet is used to update the remote
address extension of the selected subdevice. If an incoming call request packet contains
a 1980-format calling address, X25AM clears any configured remote address extension
and sets the length of the facility parameter field to 0.
Outgoing Call Accepted Packets
For outgoing call accepted packets, X25AM inserts called address extensions if the
subdevice is configured with local address extension.
Incoming Call Connected Packets
The called address extension in a call connected packet is used to update the remote
address extension of the subdevice (or the equivalent to a subdevice). If a call
connected packet contains a 1980-format called address, X25AM clears any configured
remote address extension and sets the length of the facility parameter field to 0.
Structure of NSAP Addresses
The structure of NSAP addresses reflects the hierarchy of network addressing domains
and authorities, and is defined in the document ISO 8348, Addendum 2. Figure 2-3
shows this structure. The individual parts of the address are discussed below.