Configuring and Managing Host-Based X.25 Links - Edition 6 (36939-90057)

Introduction
Configuring PAD Support and PAD Security
Chapter 1
31
• If XLA.D.O tries to call XLDD.D.O, the X.25 address 12345601 will be used as the
calling address
Figure 1-7 DTC System-to-System Switching Example
X.25 System-to-System Local Users Groups
A System-to-System Local Users Group filters call between remote systems and local
LAN-based systems. If the list exists, only those remote systems that are listed can have
access to local LAN-based systems. If there are no items in the LUG list, there is no
control on incoming and outgoing calls on the DTCs X.25 board.
Remote systems can be allowed incoming-call setup only, outgoing-call setup only, or
two-way call setup.Note that this list is referred to only for call setup; once a call is set
up, data can be exchanged in both directions. If all systems are to be permitted both
incoming and outgoing calls, you do not need to create a LUG list.
The LUG can screen incoming calls only, outgoing calls only, or both. If you list any
system as IN, be sure that you list all. The same applies to systems lists as OUT or
IN/OUT.
Example of a Local User Group
In the following diagram:
• 12345601 has IN/OUT access, because the 123456xx has IN/OUT access.
• 12345602 has IN only and 12345603 has OUT only, as addresses without wildcards
take precedence over addresses with wildcards.
X.25
DTC
X.25
XLA.D.O
01
@123456
XLB.D.O
02
XLDD.D.O
03
System to System Switching table:
System
Node Name
System
Link Name
Max
SVC
System
X.25 addresss
XLA.D.O X25LINK 64 12345601
X.25
DTC