Avaya Communication Manager Administrator's Manual page 543

Blocking prevention
Blocking occurs when insufficient B-channels required to make a call are available. Narrowband
calls require only one channel so blocking is less likely than with wideband calls which require
multiple B-channels. Blocking also occurs for wideband calls when bandwidth is not available in
the appropriate format (that is, fixed, floating, or flexible).
To reduce blocking, Communication Manager selects trunks for both wideband and narrowband
calls to maximize availability of idle fixed channels for H0, H11, and H12 calls and idle floating
channels for N x DS0 calls that require a contiguous bandwidth. The strategy for preserving idle
channels to minimize blocking depends on the channel type. The chances for blocking are
reduced if you use a flexible algorithm, assuming it is supported on the other end.
Channel Type
H0
H11
H12
Flexible NxDS0
Floating NxDS0
Administering Wideband Switching
Before you start, you need a DS1 Converter circuit pack. See the Avaya System Description
Pocket Reference for more information on the circuit pack.
To administer wideband switching:
1. On the Access Endpoint screen, administer all fields.
See Access Endpoint
2. On the PRI Endpoint screen, administer all fields.
See on page 1331 for more information.
3. On the ISDN Trunk Group screen, administer all fields.
See Trunk Group
4. On the Route Pattern screen, administer all fields.
See Route Pattern
on page 684 for more information.
on page 1535 for more information.
on page 1351 for more information.
Blocking Minimization Strategy
Preserve idle quadrants
Preserve idle facilities
Preserve idle facilities
Preserve idle facilities
Preserve idle facilities as first priority
Wideband Switching
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