Configuring X.25 Closed User Group - 3Com MSR 50 Series Configuration Manual

Configuring X.25 Closed
User Group
n
A hunt group can have 10 synchronous serial interfaces, Annex G DLCI or XOT
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channels at most.
XOT channel cannot be added to the hunt group that uses vc-number channel
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selection policy.
Overview
Closed user group (CUG) is a call restriction service provided by X.25 among all its
optional services. It governs call receiving and initiating capabilities of users (DTEs),
allowing users in the same CUG to call each other while forbidding users in
different CUGs to do so. This allows a private data communication subnet to form
over public X.25 data communications networks for an organization.
One user may belong to multiple CUGs. When the user calls another user in a
CUG, the CUG number is included in its capability negotiation message. The user
may also be set not to belong to any CUG, in which case the capability message
does not carry CUG information.
When used as data communication equipment (DCE), CUG function is shown in
the following figure.
Figure 64 CUG function implementation
Call 1
Release call
Bar incoming
Call 1: DTE originates a call, but outgoing capability is barred, so the call is
removed by DCE with CUG enabled.
Call 2: DCE receives a call request and requests a connection with DTE. CUG
function is enabled on DCE and the incoming capability is barred, so the call is
removed by DCE.
CUG function
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You must enable CUG function first before configuring it, which by default is not
enabled.
After CUG function is enabled, all calls, including those with or without CUG
facilities are suppressed. You can also define some suppression policies for CUG to
process calls in different ways.
Two types of CUG suppression policies are available. One is to suppress all
incoming calls, where the system removes the CUG facilities of all incoming calls
with CUG facilities. The other is to suppress the incoming calls matching the
mapping specified as preference rule, where the system removes the CUG facilities
Bar outgoing
X.25 network
Call 2
Release call
Configuring X.25 303