Multicast

IP multicasting is a method for sending one Internet Protocol (IP) packet simultaneously to multiple hosts. Multicast is suited to the rapidly growing segment of Internet traffic - multimedia presentations and video conferencing. For example, a single host transmitting an audio or video stream and ten hosts that want to receive this stream. In multicasting, the sending host transmits a single IP packet with a specific multicast address, and the 10 hosts simply need to be configured to listen for packets targeted to that address to receive the transmission. Multicasting is a point-to-multipoint IP communication mechanism that operates in a connectionless mode - hosts receive multicast transmissions by “tuning in” to them, a process similar to tuning in to a radio.

The NETWORK | System > Multicast page allows you to manage multicast traffic on the firewall.

• Enable Multicast - Select this option to support multicast traffic. This option is not selected by default.
• Require IGMP Membership reports for multicast data forwarding - Select this option to improve performance by regulating multicast data to be forwarded to only interfaces joined into a multicast group address using IGMP. This option is available only if Multicast is enabled. This option is selected by default.
• Multicast state table entry timeout (minutes) - Set the number of minutes that the entries in the multicast table are valid, after which the table must be regenerated. This field has a default of 5. The value range for this field is 5 to 60 (minutes). Update the default timer value in the following conditions:
  • You suspect membership queries or reports are being lost on the network.
  • You want to reduce the IGMP traffic on the network and currently have a large number of multicast groups or clients. This is a condition where you do not have a router to route traffic.
  • You want to synchronize the timing with an IGMP router.

 

• Multicast Policies
• IGMP State
• Enabling Multicast