# GnomeMeeting Manual &manrevision;

2003
Matthias Redlich
2003
Damien Sandras
2003
Christopher Warner
Christopher Warner
Damien Sandras
Matthias Redlich
Christopher
Warner
zanee
zanee@kernelcode.com
Matthias
Redlich
Damien
Sandras
This documentation is for version &appversion; of GnomeMeeting.

## What is GnomeMeeting

GnomeMeeting is a free audio/video-conferencing application for Linux and other Unices (e.g BSD or MacOSX). It was written by Damien Sandras and is licensed under the GNU/GPL. It is based on the H.323 ITU standard and allows you to make audio and video calls to remote users with H.323 hardware or software (such as Microsoft Netmeeting). It also supports all modern videoconferencing features, such as registering to an Internet Locator Service (ILS) directory, gatekeeper support, making multi-user conference calls using an external Multipoint Control Unit (MCU), using modern Quicknet telephony cards and making PC-To-Phone calls.

## Configuring GnomeMeeting for the first time

When starting GnomeMeeting for the first time the configuration druid will show automatically. The Configuration Druid is a step-by-step questionnaire that will guide you through all the steps involved in creating the basic configuration you will need to operate GnomeMeeting. You should go through all of these steps properly, otherwise the druid will re-appear (when it has not been completed) or Gnomemeeting will not function appropriately (if some of your answers have not been correct). You may run the Configuration Druid at any time from the Edit menu.

NOTE: All settings can be changed via the preferences window at anytime.

Configuration Druid Introduction

Throughout the entire configuration process navigation is available at the bottom of the window. You will be able to navigate through the questions using Back, Forward and Cancel. If you hit Cancel during the setup Gnomemeeting will not be affected by your changes and all entered information will be discarded.

This page welcomes you to the Configuration Druid. There is nothing to change or edit here. Press the 'Forward' button towards the bottom of the window to start the configuration.

Personal information

The Personal Information window requires you to supply personal information for GM usage. This information is necessary for basic functionality when connecting to other audio/video conferencing applications, as well as additional services such as user directories or gatekeepers.

As user directories do require a First Name, Surname and Email-Address, you must enter them here, before proceeding.

Callto URL

The Callto URL; Enter an email address for a callto://address (eg: callto://user@domain.com). If you leave the checkbox unchecked, your personal information will be published on the user directory of online Gnomemeeting users and you will be visible to other Gnomemeeting users. If checked then you will not be registered and will become invisible to GnomeMeeting users.

Please press 'Forward' after having entered all required information to continue.

Connection Type

Gnomemeeting supports several audio and video codecs. It includes codecs with excellent quality as well as codecs with medium to good quality. The higher the quality of a codec, the more bandwidth it requires. Thus, not every codec will work properly with a very slow network connection. This option is necessary in the initial configuration of Gnomemeeting so that it chooses the optimal codec suited for your network connection.

If your connection type is not mentioned in the list you should select the one closest to your network connect and adjust Gnomemeeting manually with the preferences window (codecs section) later on.

Audio Manager

The Audio manager manages everything audio.

Audio Devices

Gnomemeeting requires audio devices to play and record sound.

The audio output device ouputs the incoming sound stream during a call. Please select the device that your headset or speakers are connected to.

The audio input device is wehre your microphone is connected to. These settings might be the same as the settings for the audio player if you have only one soundcard. But please note that it is also possible to record sound via another device (e.g. internal microphone in a webcam) too.

It is generally recommended that you test your settings after having selected all the appropriate devices. Please press the 'Test those settings' button on the right.

If this test was successful you can continue on to the next page in the Configuration Druid. Otherwise you should change your devices and test your configuration again until you have a setup that works for you.

Video Manager

Please select the Video Manager from the list

Video Devices

This step is optional and concerns users with video devices (e.g. webcams) only. If you do not have any video devices you may skip this page. If you have a video device but it's not showing up in the selection list or you want help in setting up your video device you may refer to the following links.

http://www.exploits.org/v4l/

http://www.yolinux.com/TUTORIALS/LinuxTutorialVideo.html

If you have a webcam or video device in the list you may select it here.

Please hit the "Test those settings" button to ensure that your device works with GnomeMeeting if so, continue on with the Configuration.

Configuration Complete

The configuration of Gnomemeeting is now completed. The last window only shows a short configuration summary of the settings you have chosen. Please verify that all these settings are correct. If something is incorrect you may use the 'Back' button in the lower right hand corner of the window to move to any page of the druid and correct the mistake.

If everything is correct please press the 'Apply' button to save the configuration. The druid will be closed and the Main Window of Gnomemeeting will now appear. Remember, all settings can be changed via the preferences window at anytime.

## Usage

### Calling other users

Calling other users via Gnomemeeting is available in different forms. If you know the IP address of the party that you wish to call, you may enter that IP into the h323: input box at the top of the screen and press the Connect button; (which looks like an unplugged power socket and is conviently located to the right of the input box). eg: h323://192.168.100.1 and pressing the Connect button would call the user at that respective IP. When the call is conected and you've started communication with your party, the Connect button will now resemble a power plug connected to a socket. h323:// also supports user@hostname and example.server.com/user@hostname urls.

IPV6 - If you use literal IPv6-addresses, square brackets are required around them so that the last part of the address won't be mistaken for a port:

h323://[2001:638:500:200:210:5aff:fe4c:cfd1]

h323://[2001:638:500:200:210:5aff:fe4c:cfd1]:(portnum)

If you don't know the IP address of the party that you wish to call but have connected to an appropriate ILS (Internet Locator Server) server you may use the Gnomemeeting Address Book which is available via Tools -> Address Book. Once selected, a window should appear. At the bottom of the new window will be a drop down box with "Find all contacts" selected, here you have the option to display all contacts by clicking the Find Button, you can select from the drop down list to search for a person by First Name, Surname or Email adress. The text box to the right of the drop down list will then allow you to enter your search details, once entered press the Find button. You will then see a list of people connected to that server who you can call. Select a person from the list by double clicking on their respective name. When the call is coonected and you've started communicating with the other party, the Connect button will now resemble a power plug connected to a socket.

Calling normal phones using PC-to-Phone To be filled

Calling several participants at the same time to be filled

### GnomeMeeting during a call

Understanding the statistics

(NOTE: For a better understanding it is recommended to read the following description during a call.)

To view the statistics, please select the Statistics tab in the control panel.

The statistic visualizes the network traffic caused by GnomeMeeting. It draws a graph for each RTP stream. This means that - if audio and video is enabled in GnomeMeeting and the client of the remote party - you will see four different graphs. (incoming audio stream, incoming video stream, outgoing audio stream, outgoing video stream)

Lost packets: The percentage of lost packets

Late packets: The percentage of late packets.

Round-trip delay:

Jitter buffer: The Jitter buffer is the buffer where received sound packets are accumulated. When the buffer is full, then the sound is played. If your network is of bad quality, then you need a big jitter buffer, ie a big delay before sound is played back, because you need more time before being able to play audio back.

Adjusting the audio and video settings

Your audio and video settings can be adjusted through the control panel while you are in a call. If you want to change the audio player or audio recorder volume, select the Audio tab in the panel. The brightness, whiteness, color and contrast of your video device are changed via the Video tab.

Using text chat

Besides the communication through live audio and video streams GnomeMeeting also provides a text chat interface. This panel is opened via the text chat button in the control bar of the main window. Enter your message into the text entry box under the chat window and press enter to send it to the remote party.

NOTE: Text chat works from GnomeMeeting to GnomeMeeting clients only.

Controlling the call

GnomeMeeting supports several actions which can be performed when in a call. These actions enable you to control active sessions.

Ending a call The communication to the remote user can be ended by selecting Call->Disconnect.

Holding a call You can hold a parties call by selecting Call->Hold. This effectively pauses Video and Audio transmission, to continue transmission again you select Call->Retrieve Call and Video and Audio Transmission will begin again.

Suspend Audio (We should call this Mute) This effectively prevents all Audio communication to your respective party.

Suspend Video This effectively prevents all Video transmission to your respective party.

Taking a snapshot

While in a call you can take a snapshot of the remote party via Call -> Save Current Picture. A PNG-file will be saved in the current directory. The filename consists of three parts: the save_prefix, date and current time. (e.g. gnomemeeting-snap-2003_06_19-024316.png) The default value of save_prefix is 'gnomemeeting-snap-'.

Watching calls execution using the history windows

History windows in GnomeMeeting are comparable to logfiles. They keep chronological track of actions performed by GnomeMeeting and provide additional information to the user.

General History

The General History window keeps track of many operations which are mainly performed in the background. It displays information about audio and video devices, connections to ILS directories and gatkeepers, codecs and other details. The latest operations can be found at the bottom, older entries are shown on the top. You can access this information by opening Tools->Generic History.

Calls History

The Calls History window stores information (date, duration, URL, Software, Remote user) about all outgoing and incoming calls. They are divided into three groups - Received calls, Given calls and Unanswered calls. The first group, Received call, contains all incoming calls which were accepted by GnomeMeeting. Given calls keeps track of all attempts - succesful or not - to call another user. The last group, Unanswered calls, shows incoming calls which timed out or were rejected (if Do Not Disturb is enabled, for instance) by GnomeMeeting.

This information can be accessed by opening Tools->Calls History and by switching between the three tabs.

Resizing the video window

To resize the video window open Edit->Preferences and then proceed down to Video Devices. Highlight and select Video Devices and select the Video size. You have the option of Small or Large.

### Registering to Gatekeepers

Registering to gatekeepers

This section describes what gatekeepers are and how you can register to them.

What is a gatekeeper?

A H.323 gatekeeper controls all H.323 clients (e.g. GnomeMeeting or NetMeeting) in its zone. Although gatekeepers have a large range of different features, their most important function is to perform address translation between symbolic alias addresses and IP addresses. This means that you can use aliases instead of IP addresses to call another user. For instance, if you want to call the user "Damien" but you do not know his current IP address (dynamic IP addresses) you can easily use his alias at the gatekeeper. The gatekeeper will now direct your call to the correct IP address.

There are many reasons for users to register to a gatekeeper. An alias at a gatekeeper requires a registration, for example. Some gatekeepers do not allow unregistered users access to any of their features, in such a case you may not be able to call any user with an alias via the gatekeeper.

Registering to gatekeepers

GnomeMeeting allows you to register to one gatekeeper. All settings can be configured with the preferences window. Please select Edit-> Preferences and choose Gatekeeper Settings (located in the H.323 Settings subcategory) on the left. The display window contains all information necessary for a correct registration to a gatekeeper.

GnomeMeeting provides three different methods to register to a gatekeeper. Available values for the Registration method are as follows:

* Gatekeeper host - This method should be chosen when you know the hostname or IP address of the gatekeeper. GnomeMeeting will directly connect to the gatekeeper.

* Gatekeeper ID - This method should be used when you have a valid ID at a gatekeeper but you do not its hostname or IP address. In this case GnomeMeeting broadcasts a message and registers to the gatekeeper which answers to your ID.

* Automatically discover - If you are not sure which method to choose you can select this method. But please be aware that this method does not always work and is not recommended.

After having chosen the Registration method there are still four further fields - Gatekeeper ID, Gatekeeper host, Gatekeeper alias and Gatekeeper password. Although some fields might be optional for your local configuration it is recommended to fill in as much information as possible. The four fields should contain the following information:

* Gatekeeper ID - The Gatekeeper identifier to register with. This field is required when you have chosen Gatekeeper ID as the Registration method.

* Gatekeeper host - Hostname or IP address of the gatekeeper. This field is required when you have chosen Gatekeeper host as the Registration method.

* Gatekeeper alias - Gatekeeper alias to use when registering.

* Gatekeeper password - Password to use for H.235 authentication when registering to the gatekeeper.

Gnomemeeting will automatically register/unregister to the gatekeeper when it is started/closed.

### Registering to ILS directories

Registering to ILS directories

This section describes what ILS directories are and how you can register to them.

What is an ILS directory?

The Internet Locator Service (ILS) is a directory similar to a telephone directory. Think of it as a phone book, when you want to call someone you just look up the number for that particular person and dial away. The ILS directory operates on the same concept except in this case the number you're looking up is an IP address.

NOTE: The default ILS directory for Gnomemeeting users is ils.seconix.com, you can use any ILS directory of your choice.

Registering to an ILS directory

GnomeMeeting allows you to register to one ILS directory at a time. All settings can be configured with the preferences window. You can register to an ILS server with the following steps:

* Start Gnomemeeting

* Select Edit -> Preferences and choose "Directory Settings" (located in the General subcategory) to your left.

* Enter in the 'User Directory' input box the hostname or IP address of the ILS server you wish to register with.

* Ensure that the 'Enable Registering' check box is selected.

* You may also choose to allow other registered users to view your details (as defined in the Personal Data settings) in the user directory. If you do not select the last check box you will be invisible from other users but your callto:// address will still be functional.

Browsing an ILS directory

The ILS directory can be browsed by selecting the menu option Tools -> Address Book or by selecting the ILS address book icon from the main window. To view the updated contents of the directory click on the 'Find' box.

Searching for users

The address book can be searched on the first name, last name and email address fields. Select the field you wish to search, enter the search query and press enter.

### Managing contacts with the Address Book

Managing my contacts with the Address Book

The Address Book is a feature which allows you to find users to call and/or to save your list of persons that you call on a regular basis in a 'Group'. It loads the list of users from the ILS directory and will store callto:// URLS as well as addresses of ILS directories.

Basics of the Address Book

To open the Address Book select Tools -> Address Book and the Gnomemeeeting Addressbook window should appear. On your left there will be a list dialog showing the Servers you have added to the list as well as a list of Groups. The defaults are ils.seconix.com for Servers and Friends/Family/Work for Groups.

To receive a list of users on a certain ILS server right click on the server in question and select 'Refresh'. This will contact the server, eg: ils.seconix.com and fetch it's user list. It will then sort the user list by callto:// URL and you can now begin to contact people by double clicking on their highlighted field. You can also Drag-N-Drop to call a specific party by selecting the highlighted field and dragging it into the Main Window.

If the persons name is in the color 'red' it means that this person is in Do Not Disturb mode or currently already involved in a Gnomemeeting call with another user, the Status field 'S' will show a phone that is off the hook. The 'A' Audio field and 'V' Video field will let you know if this person has Audio or Video or Both. Should one field be selected and not the other then only one of the communication codecs are being supported by this person. For instance someone might have audio but not a webcam so only the 'A'udio field would be selected.

In certain cases you'll want to search specifically for a persons name or email on a ILS directory. For instance an ILS directory might have a large amount of people and to scroll through each and every single name looking for the one you wish to call would be time consuming. With the Addressbook you can do this by selecting from the drop down list the persons First Name, Last Name or What their Email Contains and entering the appropriate search item into the input box then select 'Refresh'.

Managing servers, groups and contacts

To add a server, highlight 'Servers' and right click. The option of adding a New server will appear. You then click on 'New Server' and at this point a dialog will appear asking you to enter the server name. Enter the name and select 'OK' and the new server should now appear in the Servers list.

To add a group, highlight 'Groups' and right click. The option of adding a New group will appear. You then click on 'New group' and at this point a dialog will appear asking you to enter the group name. Enter the name and select 'OK' and the new group should now appear in the Groups list.

To add a contact to one of your Groups you would select the Group you wish to add the contact to and right click. The option of adding a New Contact will appear and you may now enter the Contacts name and callto:// URL. After complete select 'OK' and now your contact is added to the list in that group. You can also add a contact from the ILS directory list by selecting the highlighted Contact and dragging them to the specific group you wish to add them to.

### Configuring for incoming calls

Configuring for incoming calls

GnomeMeeting supports different policies for incoming calls. Per default it displays a popup window which allows you to decide whether you want to refuse or accept the request for an incoming call. Furthermore Gnomemeeting offers three additional behaviors: Do-Not-Disturb mode, automatically answer all calls and forward calls to another host.

Do Not Disturb mode

If this mode is enabled Gnomemeeting refuses all incoming requests and only allows outgoing calls. You are not able to receive any call and do not notice if another user tries to contact you.

This mode can be enabled by selecting Call -> Do Not Disturb in the main window. Disable this feature by selecting Do Not Disturb in the call menu again.

Automatically answer calls

If this behavior is activated Gnomemeeting accepts all incoming calls. It does not display a popup window but tries to establish the connection to the remote party immediately.

Automatically answer calls has a lower priority than Do Not Disturb, of course. Thus this mode only works if the Do Not Disturb mode is disabled.

This mode can be enabled by ticking Call -> Auto answer in the main window. Disable this feature by checking Auto answer in the call menu again.

Automatically forward calls to another host

Gnomemeeting has the ability to forward calls (H.323 Call Forwarding) to another host. Which allows you to configure Gnomemeeting to forward all incoming calls to a specified host. Furthermore it is able to forward calls interactively when you do not answer the call or you are busy. In this case 'busy' means either that you are in a call currently or that you are in Do Not Disturb mode.

Call Forwarding can be configured through the preferences window. Open it by choosing Edit -> Preferences in the main window and select H.323 Advanced on the left. You will now see the section 'H.323 Call Forwarding' on the top. It contains three checkboxes for the three cases described above and one textfield for the IP address/hostname of the host the calls shall be forwarded to.

Please note that you must enter the IP address/hostname before checking one box, otherwise Gnomemeeting will display a popup window. It is also possible to combine several forwarding methods, 'no answer' and 'busy' for instance.

## Preferences

### General Preferences

General Preferences

Personal Data

This section contains Personal Information about yourself, you can substitute information in this section with anything of your choice. When finished simply press the 'Apply' button for the changes to take effect.

General Settings

Gnomemeeting GUI

Show splash screen - If enabled, Gnomemeeting will display it's splash screen on startup.

Start Hidden - If enabled, Gnomemeeting will start hidden with no windows. In order for this option to work the docklet must be enabled.

Behavior

Do not disturb - If enabled, incoming calls to Gnomemeeting from all parties will be refused.

Automatically answer calls - If enabled, incoming calls to Gnomemeeting from all parties will be accepted.

Pop window when receiving a call - If enabled a popup will be displayed when receiving an incoming phone call.

Video Display

Fullscreen width - This can be any number from 10 to 640 Fullscreen height - This can be any number from 10 to 480

Enable bilinear filtering on displayed video - If enabled, Bilinear interpolation will be used when rendering video images (this has no effect in fullscreen mode)

Sound

Play a sound on incoming calls - If enabled, Gnomemeeting will play a sound of your choice when receiving an incoming call. To change the sound use the Gnome Control Center and select 'Sound'. Gnomemeeting will be in the list of Sound Events.

3.1.3 Directory Settings

User Directory

User Directory - This is the directory server to register with. There are many ILS servers across the net however the default is for 'ils.seconix.com'.

Enable Registering - If enabled, this option will register you with the selected user directory.

Show my details to other registered users - If enabled, this option will show your details to people browsing the user directory. If disabled, you are no longer visible to people browsing the user directory but they still are able to call you using your callto URL.

Gatekeeper

Registering method - Your options are as follows, Do not register, Gatekeeper host, Gatekeeper ID, Automatically discover

Gatekeeper ID - registered ID at your local gatekeeper (optional)

Gatekeeper host - IP address/hostname of your local gatekeeper

Gatekeeper alias - your alias at the gatekeeper

Gatekeeper password - password for the authentication at your gatekeeper (optional)

Please read Registering to Gatekeepers for further information.

3.1.4 H.323 Advanced

H.323 Call Forwarding

Always forward calls to the given host - If enabled, all incoming calls will be forwarded to the host that is specified in the 'Forward calls to host' input box.

Forward calls to the given host if no answer - If enabled, all incoming calls will be forwarded to the host that is specified in the 'Forward calls to host' input box if you do not answer the call.

Forward calls to the given host if busy - If enabled, all incoming calls will be forwarded to the host that is specified in the 'Forward calls to host' input box if you are already in a call or if you are in Do Not Disturb Mode.

H.323 V2 Settings

Enable H.245 tunnelling - This enables H.245 Tunnelling mode. In H.245 Tunnelling mode H.245 messages are encapsulated into the H.225 channel (port 1720). This saves one TCP connection during calls. H.245 Tunneling was introduced in H.323v2 and Netmeeting does not support it. Using both Fast Start and H.245 Tunnelling can crash some versions of Netmeeting.

Enabled 'Fast Start' - If enabled a connection will be establish in Fast Start mode. Fast Start is a new way to start calls faster and was introduced in H.323v2. It is not supported by Netmeeting and using both Fast Start and H.245 Tunnelling can crash some versions of Netmeeting.

User Input Capabilities

User Input Capabilities - Inquire about rfcs and different input methods from Damien

NAT/PAT Router Support

Enable IP Translation - This enables IP translation. IP translation is useful if GnomeMeeting is running behind a NAT/PAT router. You have to put the public IP of the router in the field below. If you are registered to ils.seconix.com, Gnomemeeting will automatically fetch the public IP using the ILS service. If your router natively supports H.323, you can disable this.

### Codec Preferences

Codec Preferences

3.2.1 Audio Codecs

Avaliable Audio Codes as are follows:

* Speexnarrow-8k - Good Quality - 8 Kbps * MS-GSM - Good Quality - 13 Kbps * Speexnarrow-15k - Good Quality - 15 Kbps * GSM-06.10 - Good Quality - 16.5 Kbps * G.726-32k - Good Quality - 32 Kbps * G.711-uLaw-64k - Excellent - 64 Kbps * G.711-ALaw-64k - Excellent - 64 Kbps * LPC-10 - Okay - 3.46 kbits * G.723.1 - Excellent - 6.3 Kbps

NOTE: G.723.1 is a patented codec and is only available as hardware when you purchase a Quicknet card. Thus, if you don't have a Quicknet card then it won't be available as one of your choices in the above list.

3.2.2 Audio Codecs Settings

Minimum jitter buffer - range 20-1000 milliseconds

Maximum jitter buffer - range 20-1000 milliseconds

The jitter buffer is a buffer that fills in before playing back received audio packets. If the connection quality is bad, and if the audio quality is choppy, you can try to increase the maximum jitter buffer value. The current algorithim implemented in Gnomemeeting is able to automatically adjust the jitter buffer to the value giving the best audio quality in the range of values you allowed in the preferences. The default values are 20 milliseconds for the minimum and 500 milliseconds for the maximum.

Enable silence detection - If enabled, use silence detection with the GSM and G.711 codecs. Silence Detection prevents the transmitting of silence during pauses in your conversation with another party.

### Device Preferences

3.3 Device Preferences

3.3.1 Audio Devices

Audio player - Select the audio player device to use.

Audio player mixer - Select the mixer to use to change the volume of the audio player.

Audio recorder - Select the audio recorder device to use.

Audio recorder mixer - Select the mixer to use to change the volume of the audio recorder.

3.3.2 Quicknet Device

Automatic echo cancellation - The Automatic echo cancellation level: Off, Low, Medium, High, Automatic Gain Compensation, Choosing Automatic Gain Compensation modulates the volume for best quality.

Country code - The two-letter country code of your country (eg: BE, UK, FR, DE, ...).

## Configuration

### Audio Settings

4.1 Audio settings

4.1.1 Audio Devices

Playing device: The playing device setting should have a list of all the audio devices available on your system. If there are no devices listed then you will not be able to hear any audio that may be transmitted by a calling party.

Playing mixer: The playing mixer setting allows you to control the volume and any other settings available to the mixer via the playing device.

Recording device: The recording device setting should have a list of all the recording devices available on your system. If there are no devices listed then you will not be able to transmit any audio to the calling party.

Recording mixer: The recording mixer setting allows you to control the volume and any other settigns available to the mixer via the recording device.

4.1.2 Quicknet Device

This only applies if you have a Quicknet device in your system.

Echo Cancellation: (fill in here)

Country Code: (fill in here)

### Video Settings

4.2 Video settings

4.2.1 Video Devices

Video Device: Select the video device that you wish to use. Using an invalid video device or "Picture" for video transmission will transmit a test picture.

Video Size: Select the video size that you wish to use. You have the option of Small (QCIF 176x144) or Large (CIF 352x288).

Video Format: Pal (Europe), NTSC (America), Secam (France) and if you're not sure select, Auto. This option does not apply to most USB cameras.

Video Channel: Decide on the Video Channel to use

Video Image: Use this to transmit a video images to the calling party. A picture of yourself for example.

### Adjusting the Bandwidth

To be written

### Defining Ports

Setting GnomeMeeting up to use Different Ports

The main port listening for incoming connections in GnomeMeeting is port 1720, to change this port you need to load "gconf-editor". Open gconf-editor, select apps from the left hand side menu and then select gnomemeeting. Then select "ports" it should give you a list in the corresponding window to your right. Select listen_port and change it to your desired value. You can also change the UDP/RTP port range, The TCP port range and the UDP port range used to register to a gatekeeper. These are described in detail below.

Explanation of Port Ranges

1. The "listen_port" value is the port GnomeMeeting will listen for incoming connections on.

2. The "rtp_port_range" value is the range of UDP ports that GnomeMeeting will use for RTP (audio and video communication channels). You can change the UDP port range if you are using IP translation and if you need to have several GnomeMeeting running behind your NAT/PAT router. GnomeMeeting needs to be restarted for the new values to take effect.

3. The "tcp_port_range" value is the range of TCP ports beside the listen_port that GnomeMeeting will use for the H.245 channel. You can change the TCP port range if you are using IP translation and if you need to have several GnomeMeeting running behind your NAT/PAT router. GnomeMeeting needs to be restarted for the new values to take effect. This port range has no effect if both participants to the conference are using H.245 Tunneling.

4. The "udp_port_range" value is the range of UDP ports that GnomeMeeting will use when registering to gatekeepers. You can change the UDP port range if you are using IP translation and if you need to have several GnomeMeeting running behind your NAT/PAT router. GnomeMeeting needs to be restarted for the new values to take effect. This port range has no effect if you are not registering to a gatekeeper.

## Appendix

### Related Software

Gatekeepers and Proxies

Conferencing Software

Other H.323 Clients