Chapter 4: Proxy Setup

This chapter describes basic Helix Universal Proxy setup. These functions include specifying ports, binding to IP addresses, and enabling pull splitting amoung others. You may not need to change any of these settings depending on your system's configuration and the values you chose during installation.

Regardless of which features are in use, certain important settings apply to every Helix Universal Proxy. They are described in this chapter.

Basic Proxy Features

At installation, each of the methods Helix Universal Proxy uses to send clips to clients, (pass-through, cache, and pull splitting) are ready to use immediately. There is no need to perform further configuration for basic proxy features to work. This section provides additional information in case you choose to add more functionality.

Pass-through

Pass-through mode is always enabled. It can't be turned on or off.

Cache

The media cache is enabled by default. You do not need to make any changes to begin using the cache automatically.

The cache feature uses the following settings, which are pre-configured:

• Enable Caching—the feature is set to Enabled by default.
• Maximum Cache Size—This is the largest the cache will grow before removing Least Requested URLs (see "Changing the Size of the Cache" below).
• Cache Directory—The directory location of the main cache file structure. The default directory is Cache.

Changing the Size of the Cache

Once the cache has reached its maximum size, Helix Universal Proxy removes the media which were requested the least often. This method is called Least Recently Used.

Tip: It's a good idea to make the cache size as large as you can, since the more you can cache, the more bandwidth you can conserve.

To change the size of the cache:

1. In Helix Administrator, click Proxy Setup. Click Cache.
2. In the Maximum Cache Size list, type the largest size you want the cache to reach, in megabytes. (The default value is 1000 megabytes. The minimum value you can use is 11 megabytes.)
3. Click Apply.

Pull Splitting

When a client requests a live stream, Helix Universal Proxy checks to see if the Helix Universal Server acting as an origin transmitter is configured for pull splitting. Helix Universal Proxy then gets the live stream using the highly efficient pull splitting connection.

Pull splitting is enabled by default.

Helix Universal Proxy uses the following settings to perform pull splitting (you can view them by clicking Proxy Setup>Splitting in Helix Administrator), and they are pre-configured:

• Attempt to Split All Live Broadcasts— enables/disables Helix Universal Proxy's ability to use pull splitting.
• Live Splitting Transport— Defines the transport-layer protocol to use with pull splitting. Initially, Helix Universal Proxy expects to receive origin transmitter streams using the UDP transport. If UDP traffic is prohibited to the Helix Universal Proxy, it will automatically attempt TCP. Automatic transport negotiation can be disabled by configuring the proxy to always use UDP or TCP.

Note: Note that origin transmitter streams arriving at the Helix Universal Proxy using TCP may result in client rebuffering or greater start-up latency upon client connection.

• Enable Resends— In the case of network transmission errors, this setting allows data packets to be resent. By default, this feature is enabled.

Pull splitting with RealSystem Server version 8

If you are using RealSystem Server 8 with Helix Universal Proxy for pull splitting, you'll need to modify the value of a variable in Helix Universal Proxy's configuration file, rmproxy.cfg.

Warning! Because editing the configuration file with a text editor can potentially disable Helix Universal Proxy, be sure to read Appendix A before attempting modifications.

To enable pull splitting with RealSystem Server version 8:

1. Make sure Helix Administrator is not in use.
2. Open the configuration file in a text editor. (The default configuration file is rmproxy.cfg, located in the main Helix Universal Proxy installation directory.)
3. Find the variable Splitter_DoubleURLEnable, and change its value from
   0 to 1. This is how the variable should appear:
   <Var Splitter_DoubleURLEnable="1"/>
4. Save and close the configuration file.

Multicasting

Multicasting is enabled by default. Instructions on configuring Helix Universal Proxy to perform multicasting are located in Chapter 8, "Multicasting".

Defining Communications Ports

At installation, you created port settings which tell Helix Universal Proxy where to listen for requests using a particular protocol. You can view the settings from Helix Administrator by clicking Proxy Setup>Ports.

• RTSP Port— the port where Helix Universal Proxy listens for RTSP requests (these begin with rtsp://). At installation, the value is 554.

Note: To use a port lower than 1024 on a UNIX system, you must be logged on as super-user.

• PNA Proxy Port—the port where Helix Universal Proxy listens for material requested using PNA (these begin with pnm://). The default value is 1090.
• MMS Port—the port where Helix Universal Proxy listens for MMS requests (for live or on-demand Windows Media clips). The default value is 1755.
• Admin Port—port number to which Helix Administrator connection requests are directed. The value for this setting is selected at random during setup to ensure security, and can be overridden by the user during setup.

If you change the port numbers for RTSP Port and PNA Port after setting up clients for the first time you will need to reconfigure RealNetworks media players to include the new ports. (If Helix Universal Proxy is no longer listening on ports designated in the client, it will not receive the request.)

The same is true if you change the port number for MMS Port. You'll need to reconfigure Windows Media Player to include the new port number.

Note: If your Helix Universal Proxy and another application that uses ports are on the same machine, you may need to modify the HTTP Port setting. See "Running Other Applications and Helix Universal Proxy on the Same System" for additional information.

In addition to the actual port settings, there are other global settings that deal with how ports operate on Helix Universal Proxy. Descriptions for these features are as follows:

• Create user names and passwords for Administrators—clicking on the word "Create" takes you to Security>Realms, where you can create new administrator user names and passwords for Helix Universal Proxy. For more information, see "Authenticating Helix Administrator Users".
• UDP Resend Port Range—blank by default. Forces Helix Universal Proxy to use a minimum number of UDP ports to service UDP replies from client software. Enter a minimum range of two ports for each CPU. For more information, see "Modifying Shared UDP Port Ranges".

Binding To An IP Address

When Helix Universal Proxy starts, it uses the IP address assigned to the first network interface it finds on the computer—network interface 0. In a computer with multiple network interfaces—often referred to as a multi-homed machine—you can configure Helix Universal Proxy always to use specific IP addresses. Through this feature, you can select individual IP addresses to use, or you can bind to all the IP addresses on the machine.

Using Localhost

By default, Helix Universal Proxy binds to the localhost address (also called the loopback address), which enables a simulated network connection from Helix Universal Proxy to a client installed on the same computer. When using this address, which is useful for testing, no information is sent over the network, but it appears as if the connection came from the network. You can express this address in dotted decimal form as 127.0.0.1.

Capturing All Addresses

You can use the IP binding feature to capture all addresses for Helix Universal Proxy's use. To do this, specify the IP address 0.0.0.0, and delete all others. Helix Universal Proxy will automatically bind to all addresses and to localhost. For most installations, RealNetworks recommends binding to all addresses.

Binding to Specific Addresses

If you bind Helix Universal Proxy to one or more specific addresses, Helix Universal Proxy binds only to those addresses, but not to others. In other words, it will not bind to localhost. To bind to a specific address and to localhost, you must add both to the IP binding list.

Note: If a firewall is in use, you may need to configure it to allow traffic to pass on the addresses you added to the IP Binding list. See "Working with Multiple IP Addresses" for information.

Modifying IP Addresses

You bind Helix Universal Proxy to IP addresses using Helix Administrator. You'll need to restart Helix Universal Proxy after making these changes.

To reserve IP addresses for Helix Universal Proxy:

1. In Helix Administrator, click Proxy Setup> IP Binding.
2. Click the "+" icon and type the IP address that you want Helix Universal Proxy to use into the Edit IP Address box.

Warning! Type the address carefully. If you type an IP address that does not exist on this computer, Helix Universal Proxy will not be able to restart or to start.

3. Repeat this procedure for each address on this machine that you want Helix Universal Server to use.

Warning! Use either 0.0.0.0 or specific addresses, but never both. If you use both, Helix Universal Proxy will not start.

4. Click Apply.

Managing Bandwidth

You can manage the bandwidth consumption on your network by limiting the connections made by Helix Universal Proxy, and the total bandwidth allowed between the proxy and the server, and the proxy and the client. For more information, see Chapter 9, "Bandwidth Management".

Proxy Routing

You can route streaming media traffic from one Helix Universal Proxy to various other parent proxies based on the URL received from the RealOne Player. For more information, see "Proxy Routing".

Redundant Proxies

You can set up your network so it continues to route streaming media traffic through a separate, parallel Helix Universal Proxy when the network connection to your primary Helix Universal Proxy goes down. For more information, see "Working With Redundant Proxies".

Administering Both Helix Universal Proxy and Helix Universal Server

If you are the administrator of both Helix Universal Proxy and Helix Universal Server (for example, if you administer a corporate Web presence for both internal (Helix Universal Proxy) and external (Helix Universal Server) use, or if you are an ISP host and you offer Helix Universal Server streaming services to your clients), here are some things to keep in mind:

• Configuration file—the structure of the configuration file is the same; however, certain sections are unique to Helix Universal Proxy.
• Access log—Helix Universal Proxy's access log uses a similar structure as Helix Universal Server, with additional information about the proxy appended to the end of each record.
• Pull splitting—Helix Universal Proxy's pull splitting method is nearly identical to the Helix Universal Server method of pull splitting, but Helix Universal Proxy does not need to include the transmitting Helix Universal Server in the URL.
• Multicast—Helix Universal Proxy has only one method of multicast, which is the same as Helix Universal Server's back-channel multicast. However, Helix Universal Proxy can only multicast those incoming streams which are enabled for pull splitting on the Helix Universal Server acting as the origin transmitter.
• Authentication—Like Helix Universal Server, Helix Universal Proxy authenticates users who access Helix Administrator. Unlike Helix Universal Server, however, Helix Universal Proxy does not perform authentication on a per-clip basis. Instead, it allows or denies player access to specific Helix Universal Servers by looking at the host name or address of the origin Helix Universal Server.

Running Other Applications and Helix Universal Proxy on the Same System

If you install Helix Universal Proxy on the same system as other applications that use ports to exchange data, you may need to complete additional steps to ensure that the other application (a Web server for example) and Helix Universal Proxy are not attempting to use the same ports. For example, most Web servers use port 80 for HTTP requests. During installation, Helix Universal Proxy can set the default HTTP port value to 8080, but if you decide to configure Helix Universal Proxy to use port 80 (the same port as the Web server), problems may ensue. You may have to perform the following steps:

• Choose a different port for Helix Universal Proxy to use for HTTP.
• Reserve an IP address for Helix Universal Proxy.

Change the HTTP Port Value

Helix Universal Proxy does not use the HTTP port to deliver media, however the shared code between Helix Universal Proxy and Helix Universal Server requires that an HTTP port setting be defined during the installation of Helix Universal Proxy. RealNetworks recommends accepting port 8080 to avoid conflicts.

If you do have to change the HTTP port setting after installation, you'll need to edit the configuration file, rmproxy.cfg (or one with another name) manually.

Warning! Because editing the configuration file with a text editor can potentially disable Helix Universal Proxy, be sure to read Appendix A before attempting modifications.

To modify the value of HTTP Port after installation of Helix Universal Proxy:

1. Make sure Helix Administrator is not in use.
2. Open the configuration file in a text editor. (The default configuration file is rmproxy.cfg, located in the main Helix Universal Proxy installation directory.)
3. Find the variable HTTPPort, and change its value to 8080, or another value that won't conflict with other applications.
4. Save and close rmproxy.cfg.

Set IP Binding List

You may need to reserve at least one IP address for Helix Universal Proxy's use, and instruct your Web server not to use that address. This requires a multihomed machine. See "Binding To An IP Address".

Setting UNIX Features

Setting User and Group Names

By default, Helix Universal Proxy on UNIX uses the user and group names of the person who starts it. After startup, though, it can immediately switch to a different user and group setting. This lets you start Helix Universal Proxy as root, so that it can capture port 554 for RTSP communications, then assume a different user and group identity. The user and group names must be predefined through the operating system, and must have write permission for Helix Universal Proxy's Logs and Cache directories, also the Helix Universal Proxy configuration file.

To change the group or user names:

1. In Helix Administrator, click Proxy Setup>User/Group Name.
2. Type the user name or ID number in the User Name or ID box. The default is %-1, which means Helix Universal Proxy uses the name of the user who logged in and started Helix Universal Proxy.
3. Type the user name or ID number in the Group Name or ID box. The default is %-1, which means that Helix Universal Proxy uses the group name of the user who logged in and started Helix Universal Proxy.
4. Click Apply.

Setting Processor Count

On systems with multiple CPU processors, the ProcessorCount variable should be set to the number of processors available to Helix Universal Proxy. If this variable is not present, Helix Universal Proxy will use its automatic processor test, but the test may not be accurate if the system is busy doing other things when the test is performed. In addition, if you are running Helix Universal Proxy with a user ID other than root, the CPU detection system is not enabled.

The default value of 0 for the ProcessorCount variable means that Helix Universal Proxy will use its test to determine the number of processors available. If you have more than one processor on your system, you should manually configure the processor count by editing the configuration file (be sure to make a backup copy of the configuration file before you begin editing).

1. Open your rmproxy.cfg file and edit the <Var ProcessorCount="0"/> variable to the proper number of processors on your machine. For example, on a host system with two processors, the setting is:

<Var ProcessorCount="2"/>

2. Save the changes made to your configuration file.
3. Start the rmproxy process with the --sct command. For example:

./rmproxy ../rmproxy.cfg -m 512 --sct &

starts Helix Universal Proxy with 512 MB of memory while skipping the CPU detection test.

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