Nortel BCM 3.7, Manual

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Programming Operations Guide
Chapter 35
Configuring QoS monitor
The IP telephony Quality-of-Service (QoS) Monitor periodically monitors the delay and
packet-loss of IP networks between two peer gateways. The Business Communications Manager
QoS Monitor uses the same method as the Meridian 1 IPT. These monitoring packets are delivered
at UDP port 5000.
This section explains how to set the monitor and how to view the mean opinion score:
• “Setting the QoS monitor” on page 729
• “Viewing the QoS Monitor Mean Opinion Score” on page 729
How QoS monitoring works
There are 25 monitoring packets traveling in each direction every 15 seconds. Each monitoring
package has 88 bytes in the IP layer. These monitoring packets are equally spaced out in the
15-second interval. During this 15-second interval, the packets are sent from transmitting Business
Communications Manager system to the receiving system and then returned to the transmitting
Business Communications Manager system. This results in an
overhead in the IP layer of 293
bytes/second in one direction [(2x25x88)/15 = 293 bytes/second].
QoS Monitor works on a gateway between two Business Communications Manager systems or
between a Business Communications Manager system and a Meridian 1 IPT system. QoS Monitor
must be enabled on both ends of the connection.
For information about how to configure remote gateways, refer to the Business Communications
Manager IP Telephony Configuration Guide .
The main objective of the QoS Monitor is to allow new IP telephony calls to fall back to the PSTN
if the IP network is detected as “bad”.
Note:
The remote gateways are identified by their Published IP Addresses. If a remote
gateway is accessed through an interface with Network Address Translation (NAT)
configured, the Published IP Address must be the same as one of the Public IP Addresses.
For information about NAT, refer to
“Configuring NAT (Network Address Translation)”
on page 737 .