Wired Lan And Backbone Requirements; End-To-End Qos; Base Station Planning - Avaya DECT R4 Installation And Administration Manual

Planning an IP-DECT system

Wired LAN and backbone requirements

To ensure voice quality, perform a Network Assessment of the LAN before an installation or
when you add new applications or users.
When you design a network, ensure the following to obtain optimal performance:
The infrastructure should be connected to a switched network without hubs or repeaters.
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When you set up a network that supports both voice and data, voice and data must be on
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different VLANs.
The maximum capacity of the VoIP traffic must not exceed 25% of the network capacity.
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Maximum capacity of the network may not exceed 75% of the total capacity of the network,
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including the VoIP traffic.
The network must not use firewalls. If required, use tunneling or application aware
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firewalls.
Use a backbone of at least 100 Mbps depending on the network size.
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In a switched network, the transmission delay should not be a problem but if voice traffic is
routed, a significant transmission delay might be added. If the transmission delay is too long an
echo appears in the voice path impacting the systems voice quality. The transmission delay also
adds to the speech delay. Jitter in voice packages also adds to the speech delay.
You can use several tools from third-party vendors that can provide detailed and useful
information when performing site surveys.

End-to-end QoS

To achieve QoS for a phone call, you must manage QoS all the way between the two end
points. By following a speech packet as the packet travels along the path between the end
points, you can identify all network segments and transitions where QoS needs to be managed.

Base station planning

The major task in installing an IP-DECT system is defining the number of base stations required
to cover an area to a satisfactory level. Small sites usually have a homogeneous layout, and
therefore you can easily predict and plan the field pattern of the base station. The larger sites
are more
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Avaya DECT R4 - Installation and Maintenance Guide 02/2016