System Overview - ShoreTel 4500 Installation Manual

2.1

System Overview

The SSL-based VPN Concentrator enables many remote VoIP Phones to establish secure
voice communications with a ShoreTel telephone system through SSL VPN tunnels. For
every SSL VPN tunnel, a virtual PPP interface is created on the VPN Concentrator. A PPP
peer interface is created at the remote VoIP Phone. The VoIP signaling and media streams
passing through the PPP interface within the SSL VPN tunnel are therefore completely
secure through the use of encryption in SSL.
Figure 2-1 Remote phones connectivity to Headquarters through secure SSL VPN tunnels
A maximum of 10 simultaneous SSL VPN tunnels can be licensed on the 4500/4550. A
maximum of 100 simultaneous SSL VPN tunnels can be licensed on the 5300LF/5300LF2.
WARNING:
VPN Concentrator Installation and Configuration Guide
Emergency calls from a remote VPN phone can result in serious delays
and miscommunication. If ShoreTel VPN phones will be deployed in
remote locations, emergency calls placed from these phones will be
routed to the Public Safety Answering Point (PSAP) nearest the site that
hosts the switch and VPN concentrator. If the remote ShoreTel VPN
phone is outside of the PSAP' s designated area, this will delay or prevent
an effective response.
When remotely deploying a ShoreTel VPN phone, ShoreTel strongly
recommends that you implement a 3rd-party solution which can route
emergency calls to the PSAP that is nearest to the VPN phone. If such a
solution is not available, the remote ShoreTel VPN phone should be
clearly labeled so that its users know these restrictions regarding
emergency phone call usage.
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