D-Link DCS-7110 User Manual page 40

Configuration
Multicast
You may choose to enable multicast for your camera audio and video streaming so
that your camera(s) (sources) and the receivers (clients) can establish the connection
to send and receive content.
Multicast sends a stream to the multicast group address and allows multiple clients to
acquire the stream at the same time by requesting a copy from the multicast group
address. Therefore, enabling multicast can effectively save network bandwidth.
Multicast group address: A Multicast group address is used to send and receive
content. Sources use this group address as the destination address while sending their
data packets. Receivers use this group address to inform the network that they are
interested in receiving packets sent to that group.
Multicast video port: By default, the video port is set to 5556. You can assign it to
another port number between 1025 and 65534. This value must be an even number.
Multicast RTCP video port: This port will always be assigned automatically depending
on the video port value.
Multicast TTL [1-255]: The multicast TTL (Time To Live) is the value that tells the router
the range a packet can be forwarded. By default, the multicast TTL value is 15.
D-Link DCS-7110 User Manual 40