Installation guide

50 Planning and Installation Guide ShoreTel 14.2
Network Requirements and Preparation Distributed Call Control Signaling
3
Distributed Call Control Signaling
Voice switches maintain communication with each other. A single voice switch maintaining basic
connectivity with 59 other voice switches consumes less than 1.5 Kbps of bandwidth.
Admission Control in the Wide Area Network
To ensure that voice traffic does not overwhelm your wide area network and degrade voice quality, the
ShoreTel system has an Admission Control feature. From ShoreTel Director, you can limit the amount
of WAN bandwidth used for telephone calls on a per-site basis. For a telephone call to be established
between sites, admission control must be met at both sites. If the admission control limit is reached at
a site, additional calls cannot be placed to or from the site, thus ensuring the voice quality of calls
already in progress. If the user is making an outbound call, the call is automatically routed out of a
trunk at the site. When making an extension-to-extension call, the user is informed that there is
insufficient network bandwidth to complete the call. The user can try again later or dial the external
number of the other user.
If PSTN failover is enabled for a user extension, the user’s extension-to-extension calls are
automatically routed to the public switched telephone network (PSTN) when there is insufficient
bandwidth for an IP phone connection.
Spanning Tree Protocol
Spanning Tree Protocol (STP) is used by Ethernet switches and routers to determine if there are
multiple paths on the network between any two endpoints. You must disable STP on any network port
that has a ShoreTel voice switch or ShoreTel server connected.
Table 13: Typical Bandwidth Use for ShoreTel Communicator
ShoreTel Communicator Bandwidth Use
Personal .2 Kbps
Professional .2 Kbps
Operator
Extension Monitor
.2 Kbps + 1.5 Kbps
1.5 Kbps per monitored extension
Workgroup Agent
Queue Monitor
.25 Kbps
6.5 Kbps per queued call
Workgroup Supervisor
Queue Monitor
Agent Monitor
.25 Kbps
6.5 Kbps per queued call
1.5 Kbps per agent