VIVOTEK
80 - User's Manual
Multicast settings for stream 1, 2, and 3
: Click the items to display the detailed configuration
information� Select the Always multicast option to enable multicast for stream 1 or 2�
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� Therefore,
enabling multicast can effectively save Internet bandwith�
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�
If the multicast RTP video ports are incorrectly assigned, the following warning message will be
displayed:
Multicast TTL [1~255]
: The multicast TTL (Time To Live) is the value that tells the router the range
a packet can be forwarded�
Initial TTL
Scope
0
Restricted to the same host
1
Restricted to the same subnetwork
32
Restricted to the same site
64
Restricted to the same region
128
Restricted to the same continent
255
Unrestricted in scope
