TECH TIP – Videoconferencing settings for Apple AirPort Extreme wireless access point. SYMPTOM / ISSUE After connecting a set-top videoconferencing system to an Apple AirPort Extreme wireless access point (WAP), outgoing calls are successful but no inbound calls are received. APPLIES TO IP Video Endpoints NATURE OF PROBLEM A videoconferencing endpoint connected to an Apple AirPort Extreme wireless access point will typically have an internal LAN address that is behind the AirPort Extreme’s Network Address Translation (NAT) firewall. When dialing in to the system, the number dialed is usually the WAN address of a DSL or cable modem that the WAP is connected to. Until the WAP is configured, it will not know how to route the call setup data. RESOLUTION Easy way: Establish a permanent (static) IP address for the video endpoint and place that IP address in the DMZ (Apple’s term for DMZ is Default Host) so it is placed outside the firewall. This will expose it to the Internet and allow it to receive all inbound traffic. Not as easy, but still effective way: Establish a static IP address for the video endpoint and provide inbound port mapping information to the WAP. Inbound port mapping will route data coming in on specific ports used for videoconferencing to the device IP address that is to receive that data. Status Working as designed.

TO REPRODUCE: Systems needed: IP video endpoint, Apple AirPort Extreme wireless access point (steps below are based on settings using the AirPort Utility for Windows v5.3.2) Steps to reproduce: Connect the LAN port of the endpoint to a WAP LAN port. Place a call. Result: Call will connect. Call into the system from an external video conference system. No indication from the local video endpoint that there is an incoming call

RESOLUTION: From a PC connected to the AirPort Extreme, launch the Apple AirPort Utility software program and select the WAP from the list in the left column. If it doesn’t show up at first, press the ‘Rescan’ button (or Ctrl+R).

Press the Manual Setup button from the Base Station menu and connect to the WAP. Enter the password if necessary. [Note: The IP address should show the LAN address of the WAP. The ‘AirPort ID’ would show the MAC address of that unit.]

Check the ‘Allow configuration over Ethernet WAN port’ checkbox. To allow incoming traffic, press the AirPort button and select the AirPort Extreme tab. Check the ‘Allow configuration over Ethernet WAN port’ checkbox.

Next, press the Internet button and select the NAT tab. Enter the last octet of the static IP address of the videoconferencing system (253 in this case) in the Default Host window. This will place the video endpoint in the DMZ outside the firewall with direct access to the Internet.

(This will take you to the Advanced/Port Mapping tab.) Alternatively, the WAP can provide inbound port mapping. Instead of placing the IP address for the video endpoint in the DMZ, check the ‘Enable NAT Port Mapping Protocol’ checkbox. Press the ‘Configure Port Mappings . . .’ button to add the ports used for videoconferencing. (This will take you to the Advanced/Port Mapping tab.)

To add a port, press the ‘+’ button and add a service.

From the ‘Service’ drop-down menu, select ‘Custom’ From the ‘Service’ drop-down menu, select ‘Custom’. Type in 1720 for both Public and Private TCP ports. 1720 is the TCP port for H.323 call setup. Verify that the IP address shown in the ‘Private IP Address’ window matches the IP address of the video endpoint. When information is correct, press the ‘Continue’ button.

Add the name description for the port in the ‘Description’ window Add the name description for the port in the ‘Description’ window. This can be any name you choose. For easy reference, you might want to use ‘1720-H.323 call setup’.

Click on the ‘+’ button again to add other ports.

Add the TCP (3230-3239) and UDP (3230-3269) ports as shown below. Press ‘Continue’ as in the previous step to assign a name.

Press the ‘+’ button again to add a port for T Press the ‘+’ button again to add a port for T.120 content (if desired).

TCP port 1503 is used for T.120 content. Press ‘Continue’ as before to assign a name.

If SIP is desired, press the ‘+’ button again.

Add the TCP and UDP port 5060 for SIP call setup. Press ‘Continue’ again to name.

These are the combined port mappings for H These are the combined port mappings for H.323 call setup, TCP/UDP data, T.120 data and SIP call setup. With these ports mapped, videoconference traffic will be routed to the video endpoint but will allow the endpoint to reside behind the firewall on the local LAN.

Web and telnet access If web or telnet access to the video endpoint is required, it may be preferable to place it in the DMZ outside the firewall where there are no port restrictions.