Nortel Networks NN43001-307 Adaptive Network Bandwidth Management

110 Bandwidth Management

Command Description

•Type= PRIVATE/SHARED

•Strategy = BB/BQ

•ZoneIntent = MO/VTRK

Adaptive Network Bandwidth Management

CS 1000 Release 4.5 supports the Adaptive Network Bandwidth

Management feature.

The Adaptive Network Bandwidth Management feature enhances the

performance of Voice over Internet Protocol (VoIP)networks based

on real-time interaction. It provides the means to automatically adjust

bandwidth limits and take corrective action in response to Quality of Service

(QoS) feedback. This dynamic bandwidth adjustment maintains a high level

of voice quality during network degradation.

The Adaptive Network Bandwidth Management feature dynamically adapts

to QoS in the network and reduces the bandwidth available for interzone

calls if QoS degrades. Typically,each Call Server in the network has a zone

assigned to it. The Call Server keeps track of the bandwidth being used

between its own zoneand zones belonging to other Call Servers. If the QoS

degrades between the Call Server’s zone and a particular zone belonging

to another Call Server, the availablebandwidth is reduced automatically

between those two zones. When the QoS between the two zones improves,

then the bandwidth limit is allowed to return to normal.

When an IP Phone encounters degradation of the network, it informs the

Call Server through various QoS alarms. These QoS alarms (packet loss,

jitter, delay,and, for phase 2 IP Phones, R value) get reported to the Call

Server. Depending upon the rate of the incoming alarms and the value of the

alarms, the Call Server reduces the available bandwidthavailable to make

new calls. The Call Server will lower/limit the number of new calls allowed,

based on the available bandwidth. This prevents excessive calls being

placed on a network with limited bandwidth (resulting in poor voice quality).

Once the adjusted (lowered) bandwidth reaches its full capacity, new calls

are either routed to an alternate route (if available) using Network Alternate

Routing Service (NARS) , or Alternative Routing for Network Bandwidth

Management feature,or new calls are blocked. Forfurther information about

the Alternative Routing for Network Bandwidth Management feature, see

Branch Ofﬁce Installation and Commissioning (NN43001-314). The Call

Server continues to monitor thenetwork throughout the network degradation

Nortel Communication Server 1000

Main Ofﬁce Conﬁguration Guide forSRG 50

NN43001-307 02.02 Standard

Release 5.0 3 December 2007