Chapter 4 - Installing Videoconferencing Systems

Firewall and NAT Issues

A firewall protects an organization’s network by controlling data traffic from outside the network. Different types of firewalls use different techniques to provide network security, but unless the firewall is designed to work with H.323 videoconferencing equipment, it will prevent successful videoconferencing because it is designed to prevent unsolicited data from entering the network. From a functional perspective, it blocks incoming calls, and it prevents outgoing calls by blocking the call signalling from the external endpoint when the two endpoints begin the signal transaction required to set up the call.

Network Address Translation (NAT) network environments use internal IP addresses for the devices within the network, while using one external IP address to communicate with the outside world (Wide Area Network). The NAT router accepts incoming data and forwards it to the appropriate endpoint. This provides a degree of network security, as the internal IP addresses do not provide access from outside the network.

Firewalls and NAT are often used together.

Configuring the System to Operate Behind a Firewall

To make calls through a firewall, you must open the following ports and assign them to the videoconferencing system:

Table 4-1. Firewall Ports to Open for Videoconferencing

Port

 

Used for

 

 

389 (TCP)

ILS registration

 

 

 

1503

(TCP)

Microsoft NetMeeting T.120 data sharing

 

 

 

1718

(UDP)

Gatekeeper discovery

 

 

 

1719

(UDP)

Gatekeeper RAS (must be bidirectional)

 

 

 

1720

(TCP)

H.323 call set-up (must be bidirectional)

 

 

 

1731

(TCP)

Audio call control (must be bidirectional)

 

 

3230-3235

Signalling and control for audio, call, video, and

(TCP/UDP)

data/FECC

 

 

 

3603

(TCP)

Web interface

 

 

 

© Polycom, Inc.

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Polycom EX, FX, VS4000 manual Firewall and NAT Issues, Configuring the System to Operate Behind a Firewall, Port Used for
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EX, FX, VS4000, EX4000, FX4000, VS4000 specifications

Polycom is a leading name in video conferencing and collaboration solutions, and their product line, including the EX4000, FX4000, and VS4000, exemplifies their commitment to delivering high-quality communication experiences. Each of these systems is designed to meet specific needs in the realm of video conferencing.

The Polycom EX4000 is a powerful video conferencing solution tailored for small to medium-sized conference rooms. One of its main features is the use of High Definition (HD) video, ensuring that participants enjoy clear and lifelike video in every meeting. The EX4000 is equipped with the Polycom HDX technology that enables 720p resolution, ensuring that visual detail is crisp and clear. Additionally, it incorporates advanced audio technologies such as Polycom StereoSurround, which enhances the audio quality by providing a more immersive experience, making remote participants feel as if they are in the same room.

The Polycom FX4000 builds on the capabilities of the EX4000 but is designed for larger conference rooms and more complex environments. Its main distinguishing feature is the support for multiple camera angles and layouts, allowing for a more dynamic video conferencing experience. The FX4000 supports 1080p HD video, ensuring the highest video quality for large meetings. Also equipped with the latest in noise-blocking audio technology, the FX4000 minimizes distractions and enhances the clarity of conversations, which is essential in large groups where sound can become muddled.

The Polycom VS4000 provides advanced video conferencing capabilities for larger organizations with a focus on scalable solutions. It includes features such as secure multipoint video conferencing, allowing multiple locations to connect seamlessly. The VS4000 uses the Polycom Converged Conference control, which simplifies meeting management, allowing users to initiate and manage calls with ease. The VS4000’s ability to integrate with various communication and collaboration tools makes it a flexible choice for organizations looking to enhance their communication capabilities.

Overall, the Polycom EX4000, FX4000, and VS4000 represent a powerful trio of tools in video conferencing technology, each with unique features that cater to varying organizational needs. With high-definition video, advanced audio technology, and flexible integration options, these systems exemplify quality in collaborative environments, helping businesses connect better and foster teamwork, regardless of distance.
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