ADDERLink INFINITY Manual

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AdderLink Infinity browser-based configuration utility
The browser-based configuration utility within all TX and RX units req\
uires 
a network connection between the ALIF unit and a computer on the same 
network. The configuration utility allows you to perform all of the fo\
llowing 
functions:
•	 View/edit	the	IP	network	address	and	netmask,
•	 Configure	separate	IP	network	addresses	for	video,	audio	and	USB,
•	 Configure	multicast	settings	(on	RX	units),
•	 Configure	video	bandwidth	settings	(on	TX	units),
•	 View	the	current	video	output	(on	TX	units),
•	 Perform	a	firmware	upgrade,
•	 Perform	a	factory	reset.
To connect a computer system for browser-based configuration 
1	 Connect	a	suitable	network	cable	to	the	Ethernet	port	on	the	front	panel	of	
the ALIF unit.
2	 Connect	the	other	end	of	the	link	cable	to	your	network.
3 Similarly, link your computer to the same network. Note: A Gigabit 
connection is not essential for configuration purposes.
4 If not already switched on, power up your computer and the ALIF unit. Yo\
u 
are now ready to use the browser-based configuration utility. 
To access the browser-based configuration utility
1	 Temporarily	connect	the	ALIF	unit	and	a	computer	via	a	network,	as	
discussed opposite. 
2	 Run	a	web	browser	on	your	computer	and	enter	the	IP	address	of	the	ALIF	
unit, e.g. http://169.254.1.33
 The default settings are as follows: 
•	TX units - IP address: 169.254.1.33
•	RX units - IP address: 169.254.1.32 
 Where the address of a unit is not known perform a manual factory reset 
to restore the default address.
 The opening page of the ALIF configuration utility will be displayed a\
nd you 
can now use on-screen help for details of the functions that you wish to\
 
perform. 
www .adde r.comLink from Ethernet switch
[ALIF2000]	Note: Use the 
right hand Ethernet port.  
						

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Performing an upgrade
ALIF units are flash upgradeable using the method outlined here. Howev\
er, for 
larger installations we recommend that you use the AdderLink Infinity \
Manager 
(AIM) to upgrade multiple ALIF units. When using the method below, the\
 ALIF 
unit will be upgraded in sequence.
Warning: During the upgrade process, ensure that power is not 
interrupted as this may leave the unit in an inoperable state.
To upgrade a single unit via network link
1	 Download	the	latest	upgrade	file	from	the	Adder	Technology	website.	 
Note: There are separate upgrade files for TX and RX units.
2	 Temporarily	connect	the	ALIF	unit	and	a	computer	via	a	network	(see	
AdderLink Infinity browser-based configuration utility section for 
details).    
3 Run a web browser on your computer and enter the IP address of the ALIF \
unit to be upgraded.
4 Click the Firmware Upgrade link. Within the Firmware Upgrade page, click\
 
the Choose File button. In the subsequent file dialog, locate the down\
loaded 
upgrade file - check that the file is correct for the unit being upg\
raded.
5 Click the Upgrade Now button. A progress bar will be displayed (however\
, 
if your screen is connected to the unit being upgraded then video may 
be interrupted) and the indicators on the front panel will flash whil\
e the 
upgrade is in progress. 
6	 The	indicators	should	stop	flashing	in	less	than	one	minute,	after	which	the	
unit will automatically reboot itself. The upgrade process is complete.
Finding the latest upgrade files
Firmware files for the ALIF units are available from the Technical Support 
> Updates section of the Adder Technology website (www.adder.com).  
						

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Operation
In operation, many ALIF installations require no intervention once confi\
gured. 
The TX and RX units take care of all connection control behind the scene\
s so 
that you can continue to work unhindered. 
Front panel indicators
The six front panel indicators on each unit provide a useful guide to op\
eration:
NETSERAUDUSB DVIPWR
HT
IndicatorsThese six indicators clearly show the key aspects of operation:
•	NET	On	when	valid	network	link	is	present.	Flashes	when	the	unit	is	in	error.
•	SER	On	when	the	AUX	(serial)	port	is	enabled	and	active.
•	AUD	On	when	audio	is	enabled	and	active.
•	USB	On	when	USB	is	enabled	and	active.
•	DVI	On	when	either	or	both	DVI	Video	channels	are	enabled.
•	PWR Power indicator.   
						

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Further information
This chapter contains a variety of information, including the following:\
•	 Getting	assistance	-	see	right
•	Appendix A - Tips for success when networking ALIF units
•	Appendix B - Troubleshooting
•	Appendix C	-	Glossary
•	Appendix D	-	RS232	‘null-modem’	cable,	 
	General	specifications.
•	Appendix E	-	Fibre	modules	and	cables	(ALIF	2000	units	only)
•	Appendix F	-	Additional	features	available	on	ALIF2002T	
•	Safety information
•	Warranty
•	Radio frequency energy statements
Getting assistance
If you are still experiencing problems after checking the information co\
ntained 
within this guide, then we provide a number of other solutions:
•	Online solutions and updates – www.adder.com/support
 Check the Support section of the adder.com website for the latest soluti\
ons 
and firmware updates.
•	Adder Forum – forum.adder.com
 Use our forum to access FAQs and discussions.
•	Technical support – www.adder.com/contact-support-form
 For technical support, use the contact form in the Support section of th\
e 
adder.com website - your regional office will then get in contact with\
 you. 
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Appendix A
Tips for success when networking ALIF units 
ALIF units use multiple strategies to minimise the amount of data that t\
hey send 
across networks. However, data overheads can be quite high, particularly\
 when 
very high resolution video is being transferred, so it is important to t\
ake steps to 
maximise network efficiency and help minimise data output. The tips gi\
ven in 
this section have been proven to produce very beneficial results.  
Summary of steps
•	 Choose	the	right	kind	of	switch.
•	 Create	an	efficient	network	layout.
•	 Configure	the	switches	and	devices	correctly.
Choosing the right switch
Layer 2 switches are what bind all of the hosts together in the subnet. However\
, 
they are all not created equally, so choose carefully. In particular loo\
k for the 
following:
•	 Gigabit	(1000Mbps)	or	faster	Ethernet	ports,
•	 Support	for	IGMP v2 (or v3) snooping,
•	 Support	for	Jumbo frames	up	to	9216-byte	size,
•	 High	bandwidth	connections	between	switches,	preferably	Fibre	Channel.
•	 Look	for	switches	that	perform	their	most	onerous	tasks	(e.g.	IGMP 
snooping) using multiple dedicated processors (ASICS).
•	 Ensure	the	maximum	number	of	concurrent	‘snoopable	groups’	the	switch	
can handle meets or exceeds the number of ALIF transmitters that will be\
 
used to create multicast groups. 
•	 Check	the	throughput	of	the	switch:	Full	duplex,	1Gbps	up-	and	down-	
stream speeds per port.   
•	 Use	the	same	switch	make	and	model	throughout	a	single	subnet.
•	 You	also	need	a	Layer 3 switch. Ensure that it can operate efficiently as an 
IGMP Querier.  
Layer 2 (and Layer 3) switches known to work
•	 Cisco	2960
•	 Cisco	3750
•	 Cisco	4500
•	 Cisco	6500
•	 Extreme	Networks	X480
•	 HP	Procurve	2810
•	 HP	Procurve	2910
Creating an efficient network layout
Network layout is vital. The use of IGMP snooping also introduces certain 
constraints, so take heed:
•	 Keep	it	flat.	Use	a	basic	line-cascade	structure	rather	than	a	pyramid	or	tree	
arrangement.
•	 Keep	the	distances	between	the	switches	as	short	as	possible.
•	 Ensure	sufficient	bandwidth	between	switches	to	eliminate	bottlenecks.
•	 Where	the	AIM	server	is	used	to	administer	multiple	ALIF	transceivers,	
ensure the AIM server and all ALIF units reside in the same subnet. 
•	 Do	not	use	VGA	to	DVI	converters,	instead	replace	VGA	video	cards	in	older	
systems with suitable DVI replacements. Converters cause ALIF TX units t\
o 
massively increase data output.
•	 Wherever	possible,	create	a	private	network.		
The recommended layout
The layout shown below has been found to provide the most efficient ne\
twork 
layout	for	rapid	throughput	when	using	IGMP	snooping:
•	 Use	no	more	than	two	cascade	levels.
•	 Ensure	high	bandwidth	between	the	two	L2	switches	and	very	high	
bandwidth	between	the	top	L2	and	the	L3.	Typically	10GB	and	20GB,	
respectively	for	48	port	L2	switches.
continued
Layer 2 Switch
Layer 2 Switch20G
B link
10 GB  link
1GB links
ALIF TX ALIF TX
ALIF RX
ALIF RX
ALIF RX
ALIF RX
ALIF RX ALIF RX
ALIF RX
ALIF RX ALIF RX
ALIF TX
Layer 3 Switch
(Querier)
For the latest list of switches known to work 
with ALIF and setup instructions for them, 
please go to www.adder.com
•	 H3C	5120
•	 HuaWei	Quidway	
s5328c-E1	(Layer	3)   
						

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Configuring the switches and devices
The layout is vital but so too is the configuration:
•	 Enable	IGMP Snooping	on	all	L2	switches.
•	 Ensure	that	IGMP Fast-Leave is enabled on all switches with ALIF units 
connected directly to them.
•	 Enable	the	L3	switch	as	an	IGMP Querier.
•	 Enable	Spanning Tree Protocol (STP) on all switches and importantly also 
enable portfast (only) on all switch ports that have ALIF units connec\
ted. 
•	 If	any	hosts	will	use	any	video	resolutions	using	2048	horizontal	pixels	(e.g.	
2048	x	1152),	ensure	that	Jumbo Frames are enabled on all switches.
•	 Choose	an	appropriate	forwarding	mode	on	all	switches.	Use	Cut-through 
if available, otherwise Store and forward.
•	 Optimise	the	settings	on	the	ALIF	transmitters:
•	 If	colour	quality	is	important,	then	leave	Colourdepth	at	24	bits	and	
adjust other controls,
•	 If	moving	video	images	are	being	shown	frequently,	then	leave	Frame	
Skipping at a low percentage and instead reduce the Peak bandwidth 
limiter and Colourdepth.
•	 Where	screens	are	quite	static,	try	increasing	the	Background	Refresh	
interval and/or increasing the Frame skipping percentage setting.
 Make changes to the ALIF transmitters one at a time, in small steps, and\
 
view typical video images so that you can attribute positive or negative\
 
results to the appropriate control.
•	 Ensure	that	all	ALIF	units	are	fully	updated	to	the	latest	firmware	version	(at	
least	v2.1).   
						

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Appendix B
Troubleshooting
Problem: The video image of the ALIF receiver shows horizontal lines 
across the screen. 
This issue is known as Blinding because the resulting video image looks as 
though you’re viewing it through a venetian blind. 
When video is transmitted by ALIF units, the various lines of each scree\
n are 
divided up and transmitted as separate data packets. If the reception of\
 those 
packets is disturbed, then blinding is caused. The lines are displayed i\
n place of 
the missing video data packets. 
There are several possible causes for the loss of data packets:
•	 Incorrect	switch	configuration.	The	problem	could	be	caused	by	multicast	
flooding,	which	causes	unnecessary	network	traffic.	This	is	what	IGMP	
snooping is designed to combat, however, there can be numerous causes of\
 
the flooding. 
•	 Speed/memory	bandwidth	issues	within	one	or	more	switches.	The	speed	
and capabilities of different switch models varies greatly. If a switch \
cannot 
maintain pace with the quantity of data being sent through it, then it w\
ill 
inevitably start dropping packets.
•	 One	or	more	ALIF	units	may	be	outputting	Jumbo	frames	due	to	the	video	
resolution	(2048	horizontal	pixels)	being	used.	If	jumbo	frames	are	output	
by an ALIF unit, but the network switches have not been configured to \
use 
jumbo frames, the switches will attempt to break the large packets down \
into standard packets. This process introduces a certain latency and cou\
ld be 
a cause for dropped packets.
•	 One	or	more	ALIF	units	may	be	using	an	old	firmware	version.	Firmware	
versions	prior	to	v2.1	exhibited	an	issue	with	the	timing	of	IGMP	join	and	
leave commands that caused multicast flooding in certain configurati\
ons.
Remedies: 
•	 Ensure	that	IGMP snooping is enabled on all switches within the subnet.
•	 Where	each	ALIF	unit	is	connected	as	the	sole	device	on	a	port	connection	
to a switch, enable IGMP Fast-Leave (aka Immediate Leave) to reduce 
unnecessary processing on each switch.    
•	 Check	the	video	resolution(s)	being	fed	into	the	ALIF	transmitters.	If	
resolutions	using	2048	horizontal	pixels	are	unavoidable	then	ensure	that	
Jumbo frames are enabled on all switches.
•	 Check	the	forwarding mode on the switches. If Store and forward is being 
used, try selecting Cut-through as this mode causes reduced latency on 
lesser switch designs.  
•	 Ensure	that	one	device	within	the	subnet	is	correctly	configured	as	an	IGMP 
Querier, usually a layer 3 switch or multicast router.
•	 Ensure	that	the	firmware	in	every	ALIF	unit	is	version	2.1	or	greater.
•	 Try	adjusting	the	transmitter	settings	on	each	ALIF	to	make	the	output	data	
stream as efficient as possible. See ALIF transmitter video settings for 
details.
continued   
						

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Problem: The mouse pointer of the ALIF receiver is slow or sluggish 
when moved across the screen.
This issue is often related to either using dithering on the video outpu\
t of one or 
more	transmitting	computers	or	using	VGA-to-DVI	video	converters.
Dithering is used to improve the perceived quality and colour depth of i\
mages 
by diffusing or altering the colour of pixels between video frames. This\
 practice 
is commonly used on Apple Mac computers using ATI or Nvidia graphics car\
ds. 
VGAto-DVI	converters	unwittingly	produce	a	similar	issue	by	creating	high	levels	
of pixel background noise.
ALIF units attempt to considerably reduce network traffic by transmitt\
ing 
only the pixels that change between successive video frames. When dither\
ing 
is	enabled	and/or	VGA-to-DVI	converters	are	used,	this	can	have	the	effect	
of changing almost every pixel between each frame, thus forcing the ALIF\
 
transmitter to send the whole of every frame: resulting in greatly incre\
ased 
network traffic and what’s perceived as sluggish performance.
Remedies:
•		 Linux	PCs	
 Check the video settings on the PC. If the Dither video box option is 
enabled, disable it.
•		 Apple	Mac	with	Nvidia	graphics
 Use the Adder utility for Mac’s – Contact technical support.
•		 Apple	Mac	with	ATI	graphics
	 Use	the	ALIF	2000	series	unit	with	Magic	Eye	dither	removal	feature.
•		 Windows	PCs
 If you suspect these issues with PC’s, contact technical support for \
assistance.
•	 Replace	old	VGA	adapters	on	host	computers	with	DVI	video	cards.
Problem: The audio output of the ALIF receiver sounds like a scratched 
record.
This issue is called Audio crackle and is a symptom of the same problem \
that 
produces blinding (see previous page). The issue is related to missing\
 data 
packets.
Remedies: 
As per blinding discussed previously. 
Problem: AIM cannot locate working ALIF units.
There are a few possible causes:
•	 The	ALIF	units	must	be	reset	back	to	their	zero	config	IP	addresses	for	AIM	
discovery. If you have a working network of ALIF’s without AIM and th\
en 
add AIM to the network AIM will not discover the ALIFs until they are re\
set 
to the zero config IP addresses. 
•	 This	could	be	caused	by	Layer	2	Cisco	switches	that	have	Spanning Tree 
Protocol (STP) enabled but do not also have portfast enabled on the ports 
to which ALIF units are connected. Without portfast enabled, ALIF units \
will 
all be assigned the same zero config IP address at reboot and AIM will\
 only 
acquire them one at a time on a random basis. 
 You can easily tell whether portfast is enabled on a switch that is runn\
ing 
STP: When you plug the link cable from a working ALIF unit into the swit\
ch 
port, check how long it takes for the port indicator to change from oran\
ge 
to green. If it takes roughly one second, portfast is on; if it takes ro\
ughly 
thirty seconds then portfast is disabled.             
Remedies: 
•	 Ensure	that	the	ALIF	units	and	the	AIM	server	are	located	within	the	same	
subnet. AIM cannot cross subnet boundaries.
•	Manually reset the ALIF units to their zero config IP addresses. 
•	 Enable	portfast	on	all	switch	ports	that	have	ALIF	units	attached	to	them	
or try temporarily disabling STP on the switches while AIM is attempting\
 to 
locate ALIF units.   
						

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Appendix C
Glossary
Internet Group Management Protocol
Where an ALIF transmitter is required to stream 
video to two or more receivers, multicasting is the 
method used. 
Multicasting involves the delivery of identical data 
to multiple receivers simultaneously without the 
need to maintain individual links. When multicast 
data packets enter a subnet, the natural reaction of 
the switches that bind all the hosts together within 
the subnet, is to spread the multicast data to all of 
their ports. This is referred to as Multicast flooding 
and means that the hosts (or at least their network 
interfaces) are required to process plenty of data that 
they didn’t request. IGMP	offers	a	partial	solution.
The	Internet	Group	Management	Protocol	(IGMP)	is	
designed to prevent multicast flooding by allowing 
Layer 3 switches to check whether host computers 
within their care are interested in receiving particular 
multicast transmissions. They can then direct multicast 
data only to those points that require it and can shut 
off a multicast stream if the subnet has no recipients.
There	are	currently	three	IGMP	versions:	1,	2	and	3,	
with each version building upon the capabilities of 
the previous one: 
•	 IGMPv1	allows	host	computers	to	opt	into	
a	multicast	transmission	using	a	Join	Group	
message, it is then incumbent on the router to 
discover when they no longer wish to receive; 
this	is	achieved	by	polling	them	(see	IGMP	
Querier below) until they no longer respond.
•	 IGMPv2	includes	the	means	for	hosts	to	opt	out	
as	well	as	in,	using	a	Leave	Group	message.	
•	 IGMPv3	encompasses	the	abilities	of	versions	
1	and	2	but	also	adds	the	ability	for	hosts	to	
specify particular sources of multicast data. 
AdderLink	Infinity	units	make	use	of	IGMPv2	
when performing multicasts to ensure that no 
unnecessary congestion is caused.
IGMP Snooping
The	IGMP	messages	are	effective	but	only	operate	
at layer 2 - intended for routers to determine 
whether multicast data should enter a subnet. 
A relatively recent development has taken place 
within the switches that glue together all of the 
hosts	within	each	subnet:	IGMP	Snooping.	IGMP	
snooping	means	these	layer	2	devices	now	have	
the	ability	to	take	a	peek	at	the	IGMP	messages.	As	
a result, the switches can then determine exactly 
which of their own hosts have requested to receive 
a multicast – and only pass on multicast data to 
those hosts. 
IGMP Querier
When	IGMP	is	used,	each	subnet	requires	one	
Layer 3 switch to act as a Querier. In this lead 
role,	the	switch	periodically	sends	out	IGMP	
Query messages and in response all hosts report 
which multicast streams they wish to receive. The 
Querier	device	and	all	snooping	Layer	2	switches,	
then update their lists accordingly (the lists are 
also	updated	when	Join	Group	and	Leave	Group	
(IGMPv2)	messages	are	received).		
IGMP Fast-Leave (aka Immediate Leave)
When a device/host no longer wishes to receive a 
multicast	transmission,	it	can	issue	an	IGMP	Leave	
Group	message	as	mentioned	above.	This	causes	
the	switch	to	issue	an	IGMP	Group-Specific	Query	
message	on	the	port	(that	the	Leave	Group	was	
received on) to check no other receivers exist on 
that connection that wish to remain a part of the 
multicast. This process has a cost in terms of switch 
processor activity and time. 
Where ALIF units are connected directly to the 
switch (with no other devices on the same port) 
then	enabling	IGMP	Fast-Leave	mode	means	
that switches can immediately remove receivers 
without going through a full checking procedure. 
Where multiple units are regularly joining and 
leaving multicasts, this can speed up performance 
considerably. 
Jumbo frames ( Jumbo packets)
Since	its	commercial	introduction	in	1980,	the	
Ethernet standard has been successfully extended 
and adapted to keep pace with the ever improving 
capabilities of computer systems. The achievable 
data rates, for instance, have risen in ten-fold leaps 
from	the	original	10Mbit/s	to	a	current	maximum	of	
100Gbit/s.	
While data speeds have increased massively, the 
standard defining the number of bytes (known 
as the Payload) placed into each data packet has 
remained resolutely stuck at its original level of 
1500	bytes.	This	standard	was	set	during	the	
original	speed	era	(10Mbits/s)	and	offered	the	best	
compromise at that speed between the time taken 
to process each packet and the time required to 
resend faulty packets due to transmission errors. 
But now networks are much faster and files/data 
streams are much larger; so time for a change? 
Unfortunately, a wholesale change to the packet 
size is not straightforward as it is a fundamental 
standard and changing it would mean a loss of 
backward compatibility with older systems.
Larger payload options have been around for a 
while, however, they have often been vendor 
specific and at present they remain outside the 
official standard. There is, however, increased 
consensus	on	an	optional	‘Jumbo’	payload	size	
of	9000	bytes	and	this	is	fully	supported	by	the	
AdderLink Infinity (ALIF) units.
Jumbo	frames	(or	Jumbo	packets)	offer	advantages	
for ALIF units when transmitting certain high 
resolution video signals across a network. This is 
because the increased data in each packet reduces 
the number of packets that need to be transferred 
and dealt with - thus reducing latency times.
The main problem is that for jumbo frames to be 
possible on a network, all of the devices on the 
network must support them.   
						

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29
Spanning Tree Protocol (STP)
In order to build a robust network, it is necessary 
to include certain levels of redundancy within the 
interconnections between switches. This will help to 
ensure that a failure of one link does not lead to a 
complete failure of the whole network.
The danger of multiple links is that data packets, 
especially multicast packets, become involved in 
continual loops as neighbouring switches use the 
duplicated links to send and resend them to each 
other. 
To prevent such bridging loops from occurring, the 
Spanning Tree Protocol (STP), operating at layer 
2, is used within each switch. STP encourages all 
switches to communicate and learn about each 
other. It prevents bridging loops by blocking newly 
discovered links until it can discover the nature of 
the link: is it a new host or a new switch? 
The problem with this is that the discovery process 
can	take	up	to	50	seconds	before	the	block	is	lifted,	
causing problematic timeouts.
The answer to this issue is to enable the portfast 
variable for all host links on a switch. This will 
cause any new connection to go immediately into 
forwarding mode. However, take particular care 
not to enable portfast on any switch to switch 
connections as this will result in bridging loops.
ALIF transmitter video settings
Each ALIF transmitter includes controls to help you 
customise how video data is transmitted. When 
configured correctly for the application, these can 
help to increase data efficiency. 
Background Refresh
The transmitter sends portions of the video image 
only when they change. In order to give the best 
user experience, the transmitter also sends the 
whole video image, at a lower frame rate, in the 
background. The Background Refresh parameter 
controls the rate at which this background image 
is	sent.	The	default	value	is	‘every	32	frames’,	
meaning that a full frame is sent in the background 
every	32	frames.	Reducing	this	to	‘every	64	frames’	
or more will reduce the amount of bandwidth 
that	the	transmitter	consumes.	On	a	high-traffic	
network this parameter should be reduced in this 
way to improve overall system performance. 
Colour Depth 
This parameter determines the number of bits 
required to define the colour of every pixel. 
The	maximum	(and	default)	value	is	‘24	bit’.	By	
reducing the value you can significantly reduce 
bandwidth consumption, at the cost of video colour 
reproduction. 
Peak Bandwidth Limiter 
The	transmitter	will	employ	a	‘best	effort’	strategy	
in sending video and other data over the IP 
network. This means it will use as much of the 
available network bandwidth as necessary to 
achieve optimal data quality, although typically 
the transmitter will use considerably less than the 
maximum available.
In	order	to	prevent	the	transmitter	from	‘hogging’	
too much of the network capacity, you can reduce 
this setting to place a tighter limit on the maximum 
bandwidth permissible to the transmitter. 
Frame Skipping
Frame	Skipping	involves	‘missing	out’	video	frames	
between those captured by the transmitter. For 
video sources that update only infrequently or 
for those that update very frequently but where 
high fidelity is not required, frame skipping is a 
good strategy for reducing the overall bandwidth 
consumed by the system.