Specifications

Network Requirements and Preparation
Planning and Installation Guide 9 – 3
Understanding the Requirements for Toll-Quality Voice
The ShoreTel 6.1 system has been designed to deliver the highest possible voice quality.
In fact, third-party testing by Miercom has confirmed that the ShoreTel 6.1 system
provides both low latency and high voice quality.
With the superior design of the ShoreTel 6.1 system, all that is needed to achieve toll-
quality voice communications is to deploy the system over a properly designed
network infrastructure. This section provides you with the background to understand
the factors involved in engineering an IP network that is ready for voice
communications.
In general, to ensure voice quality on the LAN, the ShoreTel 6.1 system must be used in
a switched Ethernet network. To ensure voice quality on the WAN, the ShoreTel 6.1
system requires that you do the following:
• Get a service level agreement (SLA) from your service provider.
• Using your routers, prioritize your voice traffic ahead of your data traffic.
• Set the ShoreTel Admission Control feature to ensure that the voice traffic does not
flood the WAN links.
With these items taken into consideration, you can simply and easily achieve toll-
quality voice using the ShoreTel 6.1 system.
The ShoreTel system has been designed to work in a multi-vendor network
environment and therefore leverages standards to ensure voice prioritization.
IP Phone Supported Methods
• Layer 2 IP Precedence (802.1p and 802.1q) (this only applies on the LAN)
• Layer 3 Differentiated Services Code Point (DiffServ/ToS)
• Layer 4 UDP 5004
ShoreGear Voice Switch Supported Methods
• Layer 3 Differentiated Services Code Point (DiffServ/ToS)
• Layer 4 UDP 5004
Network Requirements
When your voice traffic travels across your IP network, you must ensure that your
network does all of the following:
• Delivers enough bandwidth
• Meets the latency and jitter requirements
• Meets the packet loss requirements for toll-quality voice
You also need to prioritize your voice traffic over your data traffic and configure the
ShoreTel 6.1 system’s Admission Control feature.
Bandwidth Requirements
The amount of bandwidth for voice calls depends on these details:
• Number of simultaneous calls
• Voice encoding scheme in use
• Amount of signaling overhead