OSI/MHS Configuration and Management Manual

OSI Address Configuration in OSI/MHS
OSI/MHS Configuration and Management Manual—424827-003
D-6
Address Requirements for OSI/MHS
Figure D-1 shows how these addresses are used.
For OSI/MHS, IN(R) will always be the same as IN(D); that is, the address used to
respond is the same as the address used to receive incoming calls (because it is not
possible to configure IN(R) explicitly). We will therefore not consider IN(R) further. In
most cases OUT(R) will be the same as OUT(D); that is, a remote MTA will respond
from the same address that we used to call it. However OSI/MHS does not validate
values of OUT(R) that it receives, and so there are no configuration requirements
related to OUT(R).
In many cases, IN(S) will be the same as OUT(D), that is, a remote MTA will call us
using the same source address as the destination that we use to call it. In the same
way, OUT(S) will usually be the same as IN(D), that is, we will use the same source
address in outgoing associations as the address we use to listen for incoming
associations. However, there are cases where these addresses may differ, for one
reason or another, particularly with respect to the NSAP part of the address.
One important addressing component for an X.25 connection has different
requirements depending on whether the 1980 or 1984 version of X.25 is used. That
component is the X.25 NUA (network user address) or DTE address.
Figure D-1. Use of the OSI Addresses
053VST .VSD
For an incoming connection (from an adjacent MTA to OSI/MHS):
Service Connect Request
Parameters
:
Calling address,
IN(S)
Called address,
IN(D)
Service Connect Confirm
Parameters: Responding address, IN(R)
Adjacent
MTA
OSI/MHS
For an outgoing connection (to adjacent MTA):
Service Connect
Request
Parameters
:
Calling address, OUT(S)
Called address, OUT(D)
Service Connect Confirm
Parameters: Responding address,
OUT(R)
OSI/MHS
Adjacent
MTA