Avaya Communication Manager Administrator's Manual page 1774

Feature Reference
Wideband Switching
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 that 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 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
Considerations
•
For example, if the user side is provisioned to start at the high side (DS0 23) and DS0 22 is idle
but DS0 23 is active, reselect DS0 22 for the next call. This is known as linear trunk hunting. Only
the direction of hunt is administrable.
Interactions
•
Administered Connections
Provides call initiation for WAEs. All Administered Connections that originate from WAEs use
the entire bandwidth administered for WAE. The destination of an Administered Connection can
be a PRI endpoint.
•
Automatic Circuit Assurance (ACA)
Treats wideband calls as single-trunk calls so that a single ACA-referral call is made if an
ACA-referral call is required. The call is on the lowest B-channel associated with the wideband
call.
•
Call Coverage
A wideband endpoint extension cannot be administered as a coverage point in a call-coverage
path.
•
Call Detail Recording (CDR)
When CDR is active for the trunk group, all wideband calls generate CDR records. The feature
flag indicates a data call and CDR records contain bandwidth and Bearer Capability Class (BCC).
•
Call Forwarding
You must block Call Forwarding through Class of Service.
1774
Blocking Minimization Strategy
Preserve idle quadrants
Preserve idle facilities
Preserve idle facilities
Preserve idle facilities
Preserve idle facilities as first priority
Administrator's Guide for Avaya Communication Manager
November 2003