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Videoconferencing at UVa

Using the UVa Gatekeeper


There are two very good reasons for a videoconference endpoint located on the UVa network to use the UVa gatekeeper. One is that it may then use the Global Dialing Scheme (GDS). The second is that the device can be portable, using DHCP to obtain an IP network address, but still maintain the same videoconference address for use by others.

Table of Contents


The gatekeeper accepts the registrations of videoconference clients when they come online, and keeps a table that matches the videoconference address with the IP address of that client. One big advantage of this is that a client may change IP addresses, by moving to another subnet or via a DHCP change, and still be identifiable to other clients by the same videoconference address.

Here is a simple example of the information that the gatekeeper keeps:

Graphic: Relationship of Gatekeeper to Videoconference Devices
Device Video Address IP Address
VCON 00117912345
Polycom 00117945678 128.143.375.256
Other 00117998765 128.143.667.224

Multipoint videoconferences established on the Codian MCU are registered by default on the gatekeeper, making them accessible by a GDS address as well as via an IP address.

What is a Videoconference Address

Your videoconference device must have an assigned videoconference address to be used when registering with the UVa gatekeeper. This will enforce the uniqueness of the address. Like static IP addresses for computers, only one device must have that address. Having an assigned address helps guarantee that uniqueness.

All UVa videoconference addresses start with 001179 (like a common area code) followed by 5 digits unique to that device. All 11 digits comprise the videoconference address.

How to get a Videoconference Address

Contact ITS to get an address. Include your name, department affiliation, and what type of videoconference device you have.

Who may use this gatekeeper?

This gatekeeper is for the use of UVa faculty and staff and students working on academic projects. Guests at other sites may use their own GDS-enabled gatekeeper, or may access videoconferences established on the UVa Codian MCU without need for a gatekeeper registration.

Global Dialing Scheme

UVa videoconference addresses use a format that is recognized by gatekeepers at other national and international sites. The UVa gatekeeper is part of this global network. This means that a videoconference participant at one of these other GDS-compliant sites can “dial” a UVa videoconference address without having to involve network staff to set up a special peered connection, and without having to know additional network information such as the gatekeeper's address, etc. It greatly simplifies worldwide videoconferencing.

Basic Configuration Steps

In order for a client to take advantage of the gatekeeper, it needs to configure two pieces of information into the client videoconference software. One piece of information is the IP address of the gatekeeper. (UVa's gatekeeper IP address is The other is the assigned videoconference address of the client. Instructions for the VCON Armada Escort, Polycom Viewstation, Polycom PVX, and Aethra are below. If you have a different sort of client, you should look in the configuration properties for appropriate places to provide the gatekeeper and videoconference addresses. The spot for a gatekeeper address is usually obvious, but the field for the videoconference address may be labeled “User Name” or “User Number”, etc.

Graphic: Registration of Client with Gatekeeper

Firewall warning:

If the client (any type) is behind a firewall, it may not be able to receive packets from the gatekeeper, so it cannot complete a registration or use gatekeeper services. The gatekeeper is thus not a means of bypassing the restrictions of a firewall.

Polycom Viewstation Gatekeeper Configuration

Version 6.5

  1. The Polycom Viewstation startup screen has four selectable icons.
    Choose System Info.
    Graphic: Polycom Start Screen
    A screen with three choices is displayed: Diagnostics, User Setup, and Admin Setup.
  2. Choose Admin Setup.
    A popup window will display.
  3. Please enter the Admin password.
    • Select the DOT button to bring up the keyboard.
    • Remember to use the un-shift key to type lowercased letters.
    • The default setting is shifted.
    • Select the Enter key on the keyboard, then select OK.

    The Admin Setup menu is displayed. [Your ViewStation needs a password! The interface is controllable via the Web, so without a password anyone on the Internet can access and reconfigure the device. That's bad.]

  4. Choose the LAN/H.323 icon.
    Graphic: Polycom Admin Setup
    The LAN/H.323 menu is displayed.
  5. Choose the H.323 icon.
    Graphic: Polycom H.323 Setup
    The H.323 Setup menu is displayed. You have two tasks on the next menu.
  6. First, choose Setup.
    Another setup menu!
    Another H.323 Setup menu is displayed.
  7. Enter the videoconference address in the field labeled H.323 Extension. Enter all 11 digits. You can make the H.323 Name whatever you like—it won't be used for connecting to other clients.
    Graphic: Enter Videoconference Address
    Choose the Menu icon or press the MENU key on the remote to return to H.323 Setup.
  8. On the H.323 Setup menu, choose Gatekeeper.
    Graphic: Choose Gatekeeper Setup
  9. Click the Specify radio button. The field below it becomes enabled.
  10. Type the IP address of the gatekeeper in the field.
    • The address is
    • A period is automatically inserted after 3 digits.
    • When you need to insert a period for shorter fields, use the right arrow button.

    Graphic: Enter Gatekeeper address
  11. Push MENU on the remote or select the Menu icon to go back. Do this until a message is displayed saying that the unit will restart. As part of the restart the ViewStation will register with the gatekeeper.

If you would like to confirm the changes, you can look at the System Info screen and see the videoconference address displayed after the IP address. To check the gatekeeper assignment you have to repeat the steps above to get to the Gatekeeper screen. If you don't change anything you can go back to the main screen without causing a restart.

Polycom PVX Gatekeeper Configuration

  1. In the main PVX window select the Tool icon.
    Main PVX display
  2. The Setup screen is displayed. Pick the H.323 section.
    Pick H.323 section
  3. Under “Gatekeeper” pick the Specify option.
    Pick Specify
  4. The box to the right will become usable. Fill in the UVa gatekeeper address.
    Fill in Gatekeeper address
  5. On the same screen, fill in your videoconference address.
    Fill in Videoconference address
  6. Click the Apply button. This will cause gatekeeper registration to immediately be attempted. The result will be displayed as text under the address box.
  7. Select the Directory section.
    Go to Directory section
  8. Select the “Dial Using H.323 Extension” box.
    Choose Dial Using H.323 Extension
  9. Select OK to close the configuration screen.

VCON Gatekeeper Configuration

MeetingPoint Version 4.6

  1. Select the Earth icon on the Conference Panel to get a pull-down menu.
    Graphic: VCON Properties
  2. Select the Properties option.
    Graphic: VCON Communication  Setup
    Type the videoconference address (all 11 digits) in the User Number field. All UVa videoconference addresses start with “001179”. Type the gatekeeper IP in the Gatekeeper Address field (
  3. Select another option (such as Conversation) to force MeetingPoint to ask whether to save your changes. Select YES. A dialog box will then indicate that the application should be closed and restarted in order for this change to take effect. Do this by choosing the Exit option on the Earth pulldown menu.

Aethra Gatekeeper Configuration

Based on the Vega X3 Interface

  1. Beginning at the initial screen, select Settings.
    Graphic: Aethra Home
  2. Select Installation at bottom left.
    Graphic: Aethra Installation Setup
    The unit password must be entered before you can proceed. A popup window appears:
    Aethra Password Entry Field
    Enter the numeric password. The Installation screen appears.
  3. Select Network Interfaces.
    Graphic: Aethra Network Interfaces
  4. Select IP.
    Graphic: Aethra Network Choices
  5. Select H.323 Settings.
    Graphic: Aethra H.323 Settings
  6. Fill in the H.323 Name field (nice) and the H.323 Number field (crucial). The latter is the “videoconference number” obtained from the administrator. It starts with the site prefix 001179 and ends with 5 digits that uniquely identify the unit.
    Put a checkmark beside Use Gatekeeper and fill in the gatekeeper's IP address ( Then select the Advanced button beside the address.
    Aehtra Gatekeeper Settings
  7. The Advanced button opens a popup box. Enable Auto Registration. The values recorded in the two fields are 90 and 30. There is normally no need to alter these values.
    Aethra Advanced Popup
  8. Return to the Home screen (for a shortcut, use the remote key that has a house on it, located in the third row). Information about the Aethra network connection is overlaid on the camera display. The value entered in the H.323 Number field is labeled E.164.
    Graphic: Aethra overlay

  Page Updated: Friday 2012-04-27 16:46:30 EDT