Table 49. Establishing Incoming X.25 Circuits for Closed User Groups
Incoming
Call
Request
Contains
Receiving DTE CUG Definition
Interface
CUG Only
Protocol
CUG Only
Address
Specific
CUG
Interface
and
Protocol
CUG
Interface
and
Address
CUG
Protocol
and
Address
CUG
All CUGs No CUGs
No CUG Reject Reject Reject Reject Reject Reject Reject Accept
Interface
CUG
Accept Reject Reject Reject Reject Reject Reject Reject
Protocol
CUG
Reject Accept Reject Accept Reject Reject Reject Reject
Address
Specific
CUG
Reject Reject Accept Reject Accept Accept Accept Reject
For outgoing calls on an interface, if you have enabled either the CUG or the BCUG
facility, each call request will contain the configured preferred CUG (if any) for the
destination or, if no address-specific CUG is configured, the CUG used is the CUG
defined for the protocol, or if no protocol-specific CUG is configured, the CUG used
is the CUG defined for the interface. If no CUG number has been configured, the
CUG facility is not included in any outgoing call request.
Overriding Closed User Group Processing for CUG 0
You can configure the DTE such that it does not validate incoming calls with a CUG
of 0 in the call request. This ability allows you to permit specific calls to complete
even when you have not enabled incoming access. Using the national enable cug
0 override command forces the device to ignore the CUG facility if the CUG
number is 0. The call request will not be compared with any configured CUG
number.
Configuring X.25 Closed User Groups
To use closed user groups on X.25 interfaces:
1. Request CUG numbers from your network provider. You will need these
numbers when configuring X.25.
2. Enable the closed user group facility using the national enable cug command
and related commands.
3. Enable the bilateral closed user group facility, if desired, using the national
enable bi-cug command and related commands.
4. Configure the appropriate CUG numbers for the DTEs. Specify the preferred
CUG, CUG, preferred bilateral CUG, and bilateral CUG, as needed. This is
done through the add address command.
5. Configure the appropriate CUG and bilateral CUG for the protocol, if required.
This is done through the add protocol command.
Note: You should only configure these CUGs if you are restricting all X.25
circuits established over the X.25 interface for this protocol to DTEs
belonging to this set of unique CUGs or BCUGs unless you override it
with an address-specific CUG.
6. Configure the appropriate CUG and bilateral CUG for the interface, if required.
This is done through the add cug command.
Using the X.25 Network Interface
Chapter 26. Using the X.25 Network Interface 325
