Per-call facility options - Closed User Group Selection
Per-call facility options - Closed User Group with Outgoing Access Selection
Per-call facility options - Bilateral Closed user group
Per-call facility options - Closed User Group Selection
Description of Facility
Allows the
to be specified.
Basic Format:
| Facility code | Parameter field |
| 03 hex | CUG index BCD |
| 03 | 00000011 | Closed user group selection..............#
Extended Format:
| Facility code | first 2 digits | final digits |
| 47 hex | CUG index BCD | CUG index BCD |
| 47 | 01000111 | Closed user group selection.extended.....#
A closed user group (
) permits the DTEs belonging to the closed user group to communicate with each
other but precludes communication with other users.
Each member of the CUG identifies it with a local CUG ID (1-99).
UK(a) - only supports the Basic format (ie max of 99 CUGs per line).
Limitations are:
- maximum of 99 CUGs per line
- CUG subscriptions always apply to whole line (even if multiple address are defined for the line).
- CUG number 1 is always preferential CUG
UK(b) - CUGs are supported but they may not be necessary because security
can be provided by giving the user a 'profile' which defines who can access
their circuit. Extended format of CUG not supported.
Extended format not supported.
+--------------------------------------------------------------------------------------------+
| X.2 LEVEL 3 PER CALL FACILITY | X.2 (1984) | UK(a) | UK(b) |interworking|
| OPTIONS | REF CLASS | now | now |R5a|R5b| R6 | |
+-------------------------------------+-------------+--------+-----+---+---+----+------------|
| Closed user group selection.........| 2.1 E |
|
|
|
|
|
|
| CUG extensions......................| | . | . | . | . | . | |
+--------------------------------------------------------------------------------------------+
Per-call facility options - Closed User Group with Outgoing
Access Selection
Description of Facility
Enables a DTE to belong to one or more closed user groups and to originate
calls to DTEs in the open part of the network.
Basic Format:
| Facility code | Parameter field |
| 09 hex | CUG index BCD |
| 09 | 00001001 | Closed user group outgoing access........#
Extended Format:
| Facility code | first 2 digits | final digits |
| 48 hex | CUG index BCD | CUG index BCD |
| 48 | 01001000 | Closed user group outgoing access ext....#
When the closed user group with outgoing access facility is subscribed to
and the DTE has a default CUG (known as a preferential CUG) then only the closed
user group selection facility is applicable for use at the interface.
When the closed user group with outgoing access facility is subscribed to
and the network offers to the DTE the capability of choosing whether or not
to have a preferential CUG and the DTE has no preferential CUG, then both the
closed user group facility and the closed user group with outgoing access facility
are applicable.
+--------------------------------------------------------------------------------------------+
| X.2 LEVEL 3 PER CALL FACILITY | X.2 (1984) | UK(a) | UK(b) |interworking|
| OPTIONS | REF CLASS | now | now |R5a|R5b| R6 | |
+-------------------------------------+-------------+--------+-----+---+---+----+------------|
| Closed user group with outgoing | | | | | | | |
| access selection....................| 2.14 A | . |
|
|
|
| |
+--------------------------------------------------------------------------------------------+
Extended format not supported.
RD 0004 part 8:1.C (PICS proforma Public Network1984)
FS4b - CUG selection with outgoing access
- basic format ........ O = Optional
FS4e - CUG selection with outgoing access
- extended format ...... P = Prohibited
FR4b - CUG selection with outgoing access
- basic format ........ O = Optional
FR4e - CUG selection with outgoing access
- extended format ...... P = Prohibited
Public Network cannot accept CUG selection with O/G access.
Implementation issues
Per-call facility options - Bilateral Closed user group
Description of Facility
Allows the selection of a Bilateral Closed user group
| Facility code | first 2 digits | final digits |
| 41 hex | CUG index BCD | CUG index BCD |
| 41 | 01000001 | Bilateral Closed user group..............#
+--------------------------------------------------------------------------------------------+
| X.2 LEVEL 3 PER CALL FACILITY | X.2 (1984) | UK(a) | UK(b) |interworking|
| OPTIONS | REF CLASS | now | now |R5a|R5b| R6 | |
+-------------------------------------+-------------+--------+-----+---+---+----+------------|
| Bilateral closed user group select..| 2.2 A | . | . | . | . | . | |
+--------------------------------------------------------------------------------------------+
Not supported.
&UKa& = yUKa support
UKa release 4 does not support these facilities.
