3Com 3C10402B, Administrator'S Manual

Page: 462 / 582

462 A
PPENDIX
D: C
ONNE
X
TIONS
H.323 G
ATEWAY
The ConneXtions software adapts internal system protocols to equivalent
H.323 protocols that are carried across a WAN in IP packets. The H.323
protocol addresses:
■
Negotiated connections.
■
Negotiated voice compression.
■
Standard extensions.
■
Remote Internet device connections.
For more information, see “Overview of H.323” on page 471 .
Installation
Requirements
The ConneXtions H.323 Gateway software requires a system and at least
four additional components:
■
A router with access to a wide area network (WAN)
■
A Windows-based server connected to the NBX LAN
■
ConneXtions software (on the NBX Resource Pack CD )
■
A ConneXtions license
Systems that receive H.323 calls through the public Internet might also
need a firewall. See
“Firewall Security” page 480 .
WAN Router WAN Routers typically connect to ISDN, T1, E1, Frame Relay, or
Asynchronous Transfer Mode facilities, depending on the load they carry.
A dedicated router can often reduce problems encountered with
firewalls. Firewalls often interfere with connections because they are
designed to admit only authorized addresses, and because they
discriminate against specific types of packets. The unusual complexity of
the H.323 protocol presents special problems for firewalls because it
requires additional processing. To minimize packet delay through a
firewall, verify that the firewall is configured to give H.323 packets a high
processing priority.
During installation, you can select a range of TCP or UDP ports to use
with H.323 connections to provide more flexibility when using firewalls.
A ConneXtions gateway can use a separate network interface card to
bypass the firewall delay. However, implement this solution only if it is