Reference: Broadcast Groups Parameters
Some of the broadcast group parameters are optional and you'll normally use the defaults, but we specify them all in the above example for clarity. Let's discuss each one in turn: name attribute. Each broadcast group in the server must have a unique name. local-bind-address. This is the local bind address that the datagram socket is bound to. If you have multiple network interfaces on your server, you would specify which one you wish to use for broadcasts by setting this property. If this property is not specified then the socket will be bound to the wildcard address, an IP address chosen by the kernel. local-bind-port. If you want to specify a local port to which the datagram socket is bound you can specify it here. Normally you would just use the default value of -1 which signifies that an anonymous port should be used. This parameter is alawys specified in conjunction with local-bind-address. group-address. This is the multicast address to which the data will be broadcast. It is a class D IP address in the range 224.0.0.0 to 239.255.255.255, inclusive. The address 224.0.0.0 is reserved and is not available for use. This parameter is mandatory. group-port. This is the UDP port number used for broadcasting. This parameter is mandatory. broadcast-period. This is the period in milliseconds between consecutive broadcasts. This parameter is optional, the default value is 2000 milliseconds. connector-ref. This specifies the connector and optional backup connector that will be broadcasted (see Chapter 16, Configuring the Transport for more information on connectors). The connector to be broadcasted is specified by the connector-name attribute, and the backup connector to be broadcasted is specified by the backup-connector attribute. The backup-connector attribute is optional.