Installation guide

60 Planning and Installation Guide ShoreTel 14.2
Network Requirements and Preparation Tunneling
3
IP VPNs are typically viewed as falling into three major categories: remote access VPNs, intranets
(company site-to-site), and extranets (business-to-business). These services are used by companies
of all sizes because of the powerful combination of high-speed access links and public networks. An
example is the use of high-speed, low-cost broadband DSL connectivity to enable teleworkers or
branch offices to link securely with the company network via the Internet, as if they were accessing the
LAN, including all network applications, at the office. A sample VPN configuration is shown in Figure 1
on page 60.
Figure 1: VPN Topology
IP VPNs can be provided via hardware or software solutions located at the remote facility (branch
office or teleworker’s home) and the customer premises. These devices or solutions use technologies
such as tunneling, encryption, and authentication to guarantee secure communications across a public
infrastructure.
All the components of your ShoreTel system must exist in the same enterprise private network. VPNs
can be used to bridge your private networks across the Internet so that the networks for two buildings
are both part of the same private network. For multiple locations that share a private network,
bandwidth calculations should include the effective bandwidth inside the private network, rather than
the raw bandwidth.
Tunneling
Tunneling encapsulates one type of data packet into the packet of another protocol. Multiple tunneling
protocols are used today on the market: