Cisco Cisco IOS Software Release 12.2(2)XA
6
Release Notes for Cisco AS5350 Universal Gateways for Cisco IOS Release 12.2 XA
78-13329-01 Rev. H0
New and Changed Information
If system resources are not available to admit the call, two kinds of actions are provided: system denial
(which busyouts all of T1 or E1) or per call denial (which disconnects, hairpins, or plays a message or
tone). If the interface-based resource is not available to admit the call, the call is dropped from the
session protocol (such as H.323).
(which busyouts all of T1 or E1) or per call denial (which disconnects, hairpins, or plays a message or
tone). If the interface-based resource is not available to admit the call, the call is dropped from the
session protocol (such as H.323).
User Selected Threshold
This feature allows a user to configure call admission thresholds for local resources as well as memory
and CPU resources. The list of local resources that are configured for call admission are described in the
command description of call threshold poll-interval.
and CPU resources. The list of local resources that are configured for call admission are described in the
command description of call threshold poll-interval.
With the call admission command, a user is allowed to configure two thresholds, high and low, for each
resource. Call treatment is triggered when the current value of a resource goes beyond the configured
high. The call treatment remains in effect until current resource value falls below the configured low.
Having high and low thresholds prevents call admission flapping and provides hysteresis in call
admission decision making.
resource. Call treatment is triggered when the current value of a resource goes beyond the configured
high. The call treatment remains in effect until current resource value falls below the configured low.
Having high and low thresholds prevents call admission flapping and provides hysteresis in call
admission decision making.
With the call spike command, a user is allowed to configure the limit for incoming calls during a
specified time period. A call spike is the term for when a large number of incoming calls arrive from the
PSTN in a very short period of time (for example:100 incoming calls in 10 milliseconds).
specified time period. A call spike is the term for when a large number of incoming calls arrive from the
PSTN in a very short period of time (for example:100 incoming calls in 10 milliseconds).
Configurable Call Treatment
With the call treatment command, users are allowed to select how the call should be treated when local
resources are not available to handle the call. For example, when the current resource value for any one
of the configured triggers for call admission has reached beyond the configured threshold, the call
treatment choices are as follows:
resources are not available to handle the call. For example, when the current resource value for any one
of the configured triggers for call admission has reached beyond the configured threshold, the call
treatment choices are as follows:
•
TDM hairpinning — Hairpins the calls through the POTS dial peer.
•
Reject — Disconnects the call.
•
Play message or tone — Plays a configured message or tone to the user.
Resource Unavailable Signaling
This feature set supports the autobusyout feature where channels are busied out when local resources are
not available to handle the call.
not available to handle the call.
Autobusyout is supported on both channel associated signaling (CAS) and Primary Rate Interface (PRI)
channels.
channels.
•
CAS — Uses busyout to signal “local resources are unavailable.”
•
PRI — Uses either service messages or disconnect with correct cause-code to signal “resources are
unavailable.”
unavailable.”
PSTN Fallback
The goal of PSTN fallback is to monitor congestion in the IP network and either redirect calls to the
PSTN or reject calls based on the network congestion. Calls can be re-routed to an alternate IP
destination or to the PSTN if the IP network is found unsuitable for voice traffic at that time. The user
defines the congestion thresholds based on the configured network. This functionality enables the
service provider to give a reasonable guarantee about the quality of the conversation to their VoIP users
at the time of call admission.
PSTN or reject calls based on the network congestion. Calls can be re-routed to an alternate IP
destination or to the PSTN if the IP network is found unsuitable for voice traffic at that time. The user
defines the congestion thresholds based on the configured network. This functionality enables the
service provider to give a reasonable guarantee about the quality of the conversation to their VoIP users
at the time of call admission.