Application Note (Lw-An-001) - Lightware VINX-120AP-HDMI-ENC-DNT User Manual

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9. Appendix

9.9. Application Note (LW-AN-001)

Gigabit Network Switch Requirements For VINX Devices
Network Properties
Network-based AV products use different network protocols for
differentoperations.ThenetworkprotocolcanbeUDP/IPandTCP/
IP, the transmission mode can be Broadcast, Unicast, and Multicast.
These network protocols should be familiar to any network engineer.
Because our network-based AV solutions bridge the gap between the
audio-visual (AV) and information technology (IT) worlds, Lightware
suggests involvement of both AV and IT departments in any installation.
Lightware products are designed to be plug-and-play.The figures in
the next section illustrate the basic installation of one Decoder and
one Encoder. A video source provides the digital video content to the
Encoder which converts to Ethernet packets and sends to the attached
Decoder.TheDecoderreconstitutesthevideowithsynchronizedaudio
for presentation to the attached display.
Point-to-point vs Network Connection
VINX Encoders and Decoders have two typical applications:
▪ Point-to-point connection
▪ Point-to-multi point connection
Point-to-point Connection (Unicast mode)
Unicast transmission mode uses a one-to-one association between
the source and the destination: each destination address uniquely
identifiesasingleDecoderendpoint.
Point-to-Multi Point Connection (Multicast mode)
Multicast transmission mode uses a one-to-one or one-to-many
association; multicast datagrams are forwarded simultaneously in a
singletransmissiontomanyrecipientsthroughL2swithednetwork.
TherecanbemultipleencodersinaL2subnet.Thedecodershasto
be in the same subnet.
VINX-1x0-HDMIExtenders–User'sManual
Unicast Routing
The packet forwarding requirement of the VINX devices for point-to-
point connection is the unicast switching. Please note the unicast
mode is not the default setting of the Encoder and Decoder, users
have to set it in the devices.
Hardware Requirement:
▪ 1GbELayer2(L2)switch
ATTENTION!
VINX devices send certain system commands over
multicast packages. If the multicast packet forwarding is disabled
on the network, the signal transmission can fail.
Managed Switch for Multicast Routing
InTCP/IPterminologyLayer2isthedatalinklayerthatisresponsible
for splitting the information coming from higher layers in the TCP/
IP stack into Ethernet frames. An Ethernet frame includes, among
others, labeling information with source and destination physical
addresses (called source and destination MAC address). These
physical addresses uniquely identify the source and destination
physical devices (e.g. a VINX Encoder and a VINX Decoder). Ethernet
frames provide error resilience by incorporating a redundancy check
field through which transmission errors can easily be detected.The
device that uses only the physical address information found in the
Ethernet frame to forward a packet from one of its input ports to one
or more of its output ports is an unmanaged switch.
Amanagedswitch,ontheotherhand,canhandlethetrafficandforward
inputpacketstooutputpacketsbyutilizinginformationfromhigher
layers.Thisgivesthemanagedswitchmoreflexibilityandalsoallows
for more sophisticated functions like multicast forwarding. Since even
a simple VINX network, where one VINX Encoder supplies more VINX
Decoders, relies on multicasting, a multicast capable switch (i.e. a
managed one) is mandatory. If non-managed switches transmit the
multicastpackages,themulticasttrafficisusuallybroadcastedover
all interfaces.
Appliedfirmwarepackage:v2.0.0b27 | LDCsoftware:v1.34.0b2
Hardware Requirement:
▪ 1GbELayer3(L3)switchormanagedL2switch
Why is it important?
By default, Lightware Video-over-IP Encoders and Decoders use
multicast packet forwarding. The switches in the network shall offer
the following capabilities:
IGMPv2
▪
▪ IGMP snooping
▪ IGMP fast leave
IGMPQuerier
▪
▪ Multicastfiltering
▪ 9kMTU-Jumbo/Giantframes
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