Installation guide

Virtual LANs Network Requirements and Preparation
3
ShoreTel 14.2 Planning and Installation Guide 49
On the local area network, methods to prioritize voice packets include the following:
 IP Precedence – 5 (configurable, recommendation is 5)
 DiffServ/ToS – EF (configurable, recommendation is EF)
The Ethernet switch configuration should prioritize traffic using one of these methods. This allows the
voice traffic arriving at the switch to travel ahead of the data traffic.
ShoreTel customers typically prioritize voice traffic by setting the Differentiated Service (DiffServ) field
because this configuration is easy to set up on smart Ethernet switches.
When IP phones are used, the desktop connection to the user’s computer and phone must also be
part of the switched Ethernet network. The user’s phone is connected to the port on the Ethernet
switch, and the user’s computer or other data device is connected to the integrated two-port Ethernet
switch inside the IP phone. In this configuration, the switch port connected to the phone must be
configured to prioritize the voice packets from the phone above the data packets.
If an IP phone loses power, a PC connected through the IP phone loses its connection to the network.
Voice quality can be guaranteed by putting each of the ShoreTel voice switches and the ShoreTel
server on its own Ethernet switch port. A network with this topology meets the bandwidth, jitter, and
latency requirements for toll-quality voice without the additional need for special prioritization of voice
packets.
Virtual LANs
An alternative method to prioritize voice over data is to create a separate virtual LAN (VLAN) strictly for
your voice traffic. ShoreTel IP phones and voice switches can be configured on a specific VLAN.
Set the voice VLAN for higher prioritization in the network. The Ethernet switch infrastructure needs to
be configured to prioritize the voice VLAN. This allows the voice traffic arriving at the switch to travel
ahead of the data traffic.
Wide Area Network
To manage bandwidth in the wide area network, prioritize your voice traffic ahead of your data traffic.
You can prioritize based on the voice switch IP address, the MAC address, or the physical port on the
Ethernet switch. As an additional step, you can also prioritize the distributed call control signaling that
always travels on UDP port 5440 through UDP port 5445.
If the voice traffic for the call needs to flow across a WAN link, the router needs to be configured to
prioritize voice ahead of data using DiffServ/ToS.
Client Bandwidth
ShoreTel Communicator communicates with the ShoreTel server for call information and control,
configuration changes, and advanced services such as extension monitoring. Table 13 provides an
estimate of the client bandwidth used for each of the ShoreTel Communicator applications.