Administrator's Guide

Call coverage
Issue 5 October 2002 1543555-233-506
Whenever an incoming trunk call is redirected off-net (coverage or forwarded), a
timer is set that precludes any other incoming trunk call from redirecting off-net
until the timer either expires or is cancelled. The rationale for this mechanism is to
prevent calls that were redirected off-net from being re-routed back to the original
principal from the off-net destination, effectively creating a round-robin loop that
continuously seizes trunks until they are exhausted.
Avaya MultiVantage provides the means of performing call classification on an
off-net coverage call to determine its disposition. If the off-net call is carried
completely over ISDN facilities to its final destination, then ISDN trunk signaling
is used to monitor the call. Otherwise, the system uses a call classifier port.
When the Avaya MultiVantage tries to classify an off-net coverage call (CCRON)
using a call classifier port, the system introduces an unavoidable cut-through
delay while the call classifier port attempts to identify an answered call. Neither
the originating nor the answering party can hear each other during this delay of up
to 1 second. A call classifier is attached to all off-net coverage calls made over
analog facilities and also over ISDN facilities if the call is interworked to
non-ISDN facilities on the public network.
When the Coverage of Calls Redirected Off-Net Enabled field on the
System-Parameters Coverage-Forwarding screen is
y:
■ The system monitors off-net calls (call classification) and brings them back
to the switch if they are not answered within the defined time interval. (Set
this interval in the Off-Net Cvg Subsequent Redirection/CFWD No Ans
Interval field on the System-Parameters Coverage-Forwarding screen.)
Calls also return to the switch if the system detects a call progress tone,
such as busy or reorder.
■ A simulated bridge appearance (SBA) is put on the principal and the green
lamp is put in flashing mode; the principal can pick up the call at any time.
You have the option of dispensing with call classification (and
consequently the SBA) on a final CCRON coverage point.
■ When a call classifier port is used to classify the call, the switch plays local
ringback tone to the caller while the off-net call is being classified,
concealing from the caller what is happening on the public network. When
the call is answered off-net, it is likely that the first few syllables spoken by
the answering party will not be heard by the calling party.
■ If any party on the call is on HOLD when the call routes off net, the call
classifier is removed from the call. The call behaves in the same manner as
off-net calls when the Coverage of Calls Redirected Off-Net field is
n.