The 4300T provides the following services:
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WAN/LAN IP routing
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NAT/PAT translation for IP phones. This allows a single public IP address to
be used on the WAN link to represent all of the private IP addresses assigned
to the LAN IP phones.
•
A “VoIP” aware firewall. A full layer 7 gateway for voice traffic.
•
Traffic shaping and priority queuing to guarantee the quality of VoIP traffic.
These mechanisms protect voice and data traffic from contending for the
same network resources to guarantee low latency and the highest call quality
possible for VoIP traffic. At the same time they ensure the best utilization of
WAN bandwidth by enabling data traffic to burst up to full line rate in the
absence of voice calls. Precedence is given to traffic for the range of
addresses reserved for the IP phones.
•
Call Admission Control (CAC). CAC uses a deterministic algorithm to decide
when there are insufficient network resources available to adequately support
new calls and then return the equivalent of a “fast busy” to new call requests.
•
DHCP server and FTP/TFTP relay. These features are used to simplify and
expedite the IP configuration of phones. This also includes VoIP signaling
gateway information (MGCP and SIP).
•
Call quality monitoring and test tools.
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VoIP survivability is an orderable software option that provides local call
switching for SIP clients during a WAN link failure or lost of connectivity to a
centralized softswitch or IP PBX. This functionality also includes the ability to
make inbound and outbound calls to a local ethernet connected PSTN gateway
(SIP).
4300T configuration:
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VoIP ALG enabled
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NAT enabled
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Routing enabled
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Traffic shaping enabled
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DHCP server enabled
•
VoIP survivability enabled
Benefits
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Security of private IP addresses and voice aware firewall
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Traffic shaping prioritizing voice over data traffic.
•
Recover bandwidth for data when not used for voice
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Simplified management and administration
•
Simplified adds, moves and changes
•
Scalability – the single public IP address can continue to be used for new
subscribers to the service.
•
Increased availability of voice services through VoIP survivability.
Although not recommended the 4300T and IP phones can be installed behind an
existing enterprise firewall. In this instance the firewall will have to be configured to
allow access to and from the 4300T public IP address for the following ports:
