D-Link DCS-7517 User Manual page 44

Configuration
Unicast video transmission delivers a stream through point-to-point transmission.
Multicast, on the other hand, 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. As a result, enabling multicast can save network
bandwidth.
Multicast Group Address: An IP 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: The ports can be changed to values between 1025 and
65535. The multicast RTP port must be an even number, and the multicast RTCP
port number is the multicast RTP port number plus one, and thus is always
odd. When the multicast RTP port changes, the multicast RTCP port will change
accordingly.
Multicast TTL [1~255]: The multicast TTL (Time To Live) is the value that tells the
router the range that a packet can be forwarded.
Click an item to display its detailed configuration information. Select the Always
multicast option to enable multicast for stream 1 ~ 3.
D-Link DCS-7517 User Manual 44