Specifications

ShoreTel Server Media Communications
2
ShoreTel 14 Maintenance Guide 40
Media Communications
Media, from the perspective of the server, connects voice mail and the Auto-Attendant to switches and
endpoints via the media driver. Media travels through the ShoreTel system using Real-Time Protocol
(RTP).
A voice mail message is normal RTP traffic, unless it is a recorded voice mail message moving from
one server to another. Voice mail media streams conform to the G.711 codec. If a switch or IP phone is
configured to use G.729 or ADPCM (for example, for an intersite call), a media server proxy is used to
transcode between G.729/ADPCM and G.711. Since the media server proxy is a switch resource, there
are a limited number of G.729 proxies. If there are insufficient G.729 proxies, then ADPCM is used
instead.
Figure 12 on page 40 shows the switch-to-switch call control and media communications flows.
Figure 12: ShoreTel Server Call Control and Media Communications
Telephony Management
Service (TMS) /
Distributed Telephony
Application Service (DTAS)
Client Application
Server (CAS) / IPDS
Account Code
Collection (ACC)
= Call Control (NCC)
= Enhanced SIP Protocol
= RTP
Legend
ShoreTel
Director
Desktop and
Browser
Clients
Diagnostics &
Monitoring Server
Internet Information
Server (IIS)
Configuration
Database
Data Services
Monitoring
Database
Diagnostics & Monitoring
CDR
Database
Call Detail Reporting
Media Driver System
Voicemail
Distributed Routing
Service (DRS)
Softswitch
TAPI or ShoreTAPI
Workgroups
Headquarters Server
ShoreTel Voice Switch
ShoreTel Voice Switch
Monitoring
Service