Overall Connectivity - 3Com 3C10402B Administrator's Manual

Overall Connectivity

gateway. The remote gateway undoes the process and sends the
decompressed voice to an extension.
Connection considerations apply to two areas:
Overall Connectivity
■
Quality of Service
■
An end-to-end H.323 connection consists of a succession of Physical
Connections and Logical Connections, both local and external.
Physical Connections
An H.323 gateway has few physical connections. An installer can add an
H.323 gateway to an existing system by creating one physical connection
on the LAN that links a network interface card in an operating system to
a hub or to a switch. The same connection also gives the H.323 gateway
a direct connection to every other device on the near-end LAN. Those
devices include any 3Com Business or Basic Telephone, the Call Processor,
and the firewall or router.
Alternatively, you can use a second NIC in the gateway system to provide
a separate connection between the H.323 gateway and the IP router.
Logical Connections
Locally, every device on an NBX LAN has the same physical access to the
local network traffic as any other device. Consequently, addresses control
connections because devices can only read information that is addressed
to them. This makes addressing, and managing addresses, a key concern
for logical continuity.
Logical continuity concerns extend throughout a network connection
because the identity of a frame (or packet) and its destination determine
where it goes, how it is managed, and what happens to it.
Because so many devices share the same physical media on the Internet
and on the local network, there is always the possibility of incomplete or
degraded connections that arise from network congestion, device
configuration, or addressing problems.
Bridges, switches, routers, and firewalls can help to manage network
congestion, conversions, and security. Configuration problems with of
any of these devices can cause connection difficulties.
Connection Considerations 475