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M
ULTICAST OR
U
NICAST
?
Multicast can seem like a bandwidth-
saving miracle. Unlike NDI’s default mode (unicast), multicast does not
require a unique stream from the source to each receiver. When using unicast, each connection to the sender
reduces the bandwidth available by a similar amount.
By contrast, multicast connections do
not
add significantly to the bandwidth required as connections
multiply. You could be forgiven for wondering why anyone would ever turn this option off - yet, it is off by
default. Why?
This is because multicast requires more careful network configuration. While you might not notice any issues
in a simple network setting; a poorly configured environment can have a serious impact on more complex
networks.
•
Specifically, it is essential that IGMP snooping be enabled for each switch on the network. This lets
the device listen to traffic between other hosts, switches and routers, and identify receiving ports
using various IP multicast streams.
•
In addition, we strongly recommend that all network switche
s be of the ‘managed’ type (see the
sidebar “Managed vs. Un
-
managed”).
1.12
TALLY
Your camera
unit provides ‘tally’ notification from NDI
devices supporting it. The light located on the front of the
pedestal base will light up in red or green to tell you when
video output from the device is visible on the Program
output or Preview, as listed in the following table.
POWER
Indicates (tally state)
Green
On preview
Red
On program
Amber
On program and preview
Off
Not on output
Managed vs. Unmanaged
An un-
managed (a.k.a., ‘dumb’) network
switch will cause a multicast stream to
revert to unicast. This can have serious
ramifications.
For example, even though a device
broadcasts a multicast stream, the un-
managed switch will pass
unicast
packets to downstream switches and
clients. This can flood parts of the
network with unnecessary traffic. It can
even slow down the rest of the network,
as upstream devices are forced to wait
for responses from the over-saturated
devices.
The net result of such a poor setup can
be likened to a self-inflicted denial of
service attack.
Summary of Contents for NDI HX PTZ3
Page 1: ...Page i 01t Operating Instructions NewTek NDI HX PTZ3 IP Video Camera...
Page 30: ...Page 30 3 2 CAMERA DIMENSION MM...
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Page 66: ...Copyright 1990 2022 NewTek Inc San Antonio TX USA...
