Nortel BCM 3.7, Manual

Page: 754 / 1004

754 PPTP
N0008589 3.3
IPSec tunnel modes
In the IPSec Specification, there are two tunnel modes defined: tunnel mode and transport mode.
Business Communications Manager supports only tunnel mode. Tunnel mode describes a method
of packetizing TCP/IP traffic to create a virtual tunnel.
Tunnels are created between servers, which are also known as gateways. This is called a Branch
Office Connection. The end nodes connect to each other through gateways. These gateways set up
the tunnel over the PDN on behalf of the end nodes. The establishment of the tunnel, and the PDN
in between, is transparent to the end nodes which behave as if they are interacting through a router.
Typically, the edge devices connecting the branches of a corporation to the ISP use VPN in this
mode.
Business Communications Manager is compatible with the Contivity Extranet Switch and the
Shasta 5000.
The following sections describe configuring the tunnel portion of Business Communications
Manager using PPTP or IPSec.
PPTP
PPTP is a tunneling protocol supported by Nortel Networks, Microsoft, and other vendors. The
PPTP client is available for Windows 95 (www.microsoft.com) and is built-in to Windows 98 and
later. Third-party vendors have developed PPTP clients for Windows 3.1 and the Macintosh
operating system.
The PPTP client and PPTP server software are components on Business Communications
Manager.
This section includes information about:
• “Settings required for PPTP tunnels” on page 755
• “Changing the PPTP settings” on page 756
• “Adding a PPTP client” on page 757
• “Deleting a PPTP client” on page 758
• “Adding a PPTP tunnel” on page 758
• “Configuring a PPTP tunnel” on page 759
• “Deleting a PPTP tunnel” on page 764
• “Encryption” on page 766
Note: PPTP uses Remote Access Service (RAS) to establish connections. For this reason,
you must do some Dial Up resources configuration when you configure for some of the
PPTP configuration parameters.