Ganz ZN-CM1, Руководство пользователя

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service for exchanging data in a network which uses the Internet Protocol (IP).
UDP is an alternative to the Transmission Control Protocol (TCP). The advantage
of UDP is that it is not required to deliver all data and may drop network packets
when there is network congestion. This is suitable for live video, as there is no
point in re-transmitting old information that will not be displayed anyway.
• Unicasting is communication between a single sender and a single receiver over
a network. This means that the video stream goes independently to each user,
and each user gets their own stream. A benefit of unicasting is in case one stream
fails, it only affects one user.
• Multicast is bandwidth-conserving technology that reduces bandwidth usage by
simultaneously delivering a single stream of information to multiple network
recipients. This technology is used primarily on delimited networks (intranets), as
each user needs an uninterrupted data flow and should not rely on network
routers.
2.7 How to stream H.264
Deciding on the combination of protocols and methods to use depends on your
viewing requirements and on the properties of your network. Setting the preferred
method(s) is done in the control applet for AMC, which is found in the Windows
Control Panel. When this has been set, AMC will test all the selected methods in
the specified order, until the first functioning one is found.
RTP+RTSP
This method (actually RTP over UDP and RTSP over TCP) should be your first
consideration for live video, especially when it is important to always have an up-to-
date video stream, even if some images are lost due to network problems. This
could be configured as multicast or unicast.
Multicasting provides the most efficient usage of bandwidth, especially when there
are large numbers of clients viewing simultaneously. Note however, that a multicast
broadcast could not pass a network router unless the router is configured to allow
this. For example, it is not possible to multicast over the Internet.
Unicasting should be used for video-on-demand broadcasting, so that there is no
video traffic on the network until a client connects and requests the stream.
However, as more and more unicast clients get connected, the traffic on the
network will increase and may cause congestion. Although there is a maximum of
20 unicast viewers, note that all multicast users combined count as 1 unicast
viewer.
RTP/RTSP
This unicast method is RTP tunneled over RTSP. This could be used to exploit the
fact that it is relatively simple to configure firewalls to allow RTSP traffic.
RTP/RTSP/HTTP or RTP/RTSP/HTTPS
These two methods could also be used to traverse firewalls. Firewalls are
commonly configured to allow the HTTP protocol, allowing RTP to be tunneled.