Polycom ViewStation FX, Руководство пользователя

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Chapter 4 Advanced Configuration
© Polycom, Inc. 123 ViewStation FX/VS 4000 User’s Guide
Quality of Service (QoS), Firewalls and NAT Support
Service and Firewalls
In this screen, you can configure your quality of service, Network
Address Translator (NAT), and firewall options.
Figure 4-22. H.323 Quality of Service and Firewall Screen
The following options are configurable:
1. Use Fixed Ports— Specifies the fixed ports assigned to
ViewStation FX or VS4000 when working with a firewall.
2. IP Precedence— Specifies the priority given IP packages sent
to the ViewStation FX or VS4000.
3. Dynamic Bandwidth —Specifies use of dynamic bandwidth
allocation. ViewStation FX and VS4000 dynamic bandwidth
function automatically finds the optimum line speed for a call. If
you experience excessive packet loss while in a call, the
dynamic bandwidth function decrements the line speed until
there is no packet loss. After some time with no packet loss, the
dynamic bandwidth function incrementally increases line speed
until packet loss occurs. At this point, the dynamic bandwidth
function lowers the line speed one increment to ensure minimal
packet loss with maximum throughput. This is supported in calls
with end points that also support dynamic bandwidth.
4. System is behind a NAT —Alerts ViewStation FX or VS4000 to
use the IP address that appears in the NAT outside (WAN)