Chapter 2: Introduction
Contact Center Administrator Manual 13
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. A maximum
of 100 simultaneous SSL VPN tunnels can be licensed on the 5300.
WA R N I N G : If ShoreTel VPN phones will be deployed in remote locations, 911 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
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 911 usage.