multicast video app
TRANSCRIPT
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Multicast Solution
How does it work ?
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iMPathN e t w o r k s
Note to Viewer
The content of this tutorial provides an overview of IGMP used in
Digital Multicast networks to familiarize customers with the
technology.
The information in this document is subject to change without notifice.
While every precaution was taken in the preparation of this document,
iMPath assumes no responsibility for errors or omissions. Neither isany liability assumed for damages resulting from the use of the
information contained herein.
Should you have any questions, please feel free to contact:
Daniel Brisson
Sr. System Engineer
iMPath Networks Inc
Tel: 613-226-4000 x 297
Email: [email protected]
Gilles Lebel
Sr. System Engineer
iMPath Networks Inc
Tel: 613-226-4000 x 224
Email: [email protected]
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iMPathN e t w o r k s
Typical Network Requirements
Backbone
Monitor any video from
anywhere in the network
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iMPathN e t w o r k s
Multicast
Multicast. Allows sending one copy of each packet to the group of computers
that want to receive it. Multicast can be implemented at the Ethernet link-
layer or at the network layer (layer 3 of the OSI model). Computers join and
leave multicast groups by using the IGMP (Internet Group Management
Protocol) Each host can register itself as a member of selected multicast
groups through use of the Internet Group Management Protocol (IGMP).
Multicast is commonly used in audio and video streaming applications.
It allows a single source of traffic to be viewed by multiple destinations
simultaneously.
It is designed to provide an efficient transmission using the least amountof bandwidth on the network to save cost.
IGMP is a standard IP protocol supported by most LAN/WAN vendors in
traditional LAN products, ATM, and gigabit Ethernet solutions.
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iMPathN e t w o r k s
100 Meg
Typical Network Components
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L3 Switch/Router L3 Switch/Router L3 Switch/Router L3 Switch/Router
L3 Switch/Router L3 Switch/Router
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
Typical high speed backbone
network consisting of Layer 2
or Layer 3 Ethernet Switches.
High Speed Switches are located at major
hub locations to collect or drop off data
traffic from this distribution center.
Field hub locations are distributed where
the end devices are located. They are
used to collect and distribute traffic for
Cameras, Traffic Controllers, Message
Signs and many more.
Several topologies can be used such as
Star and Linear topologies being the most
common.
100 Meg 100 Meg
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iMPathN e t w o r k s
100 Meg
Typical Network Components
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L3 Switch/Router L3 Switch/Router L3 Switch/Router L3 Switch/Router
L3 Switch/Router L3 Switch/Router
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
The Control Centers provide
video viewing and control of
the Camera PTZ, TrafficControllers, or Message signs to
name just a few.
100 Meg 100 Meg
Multiple Control Centers may
be deployed with thisarchitecture.
The Virtual Matrix is
commonly used in digital videonetworks providing video
display and control and to
operate complementary
integrated applications.
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iMPathN e t w o r k s
100 Meg
Why use IGMP?
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
100 Meg 100 Meg
Without IGMP support, multicast traffic is
transmitted to all the ports in each network switch.
This unnecessary traffic floods the interfaces and
can quickly bog down the entire network.
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iMPathN e t w o r k s
100Base-T
Why use IGMP?
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
100Base-T
For example:
With 25 cameras deployed,each transmitting at 5 Mbps,
you will have over 125 Mbps of
combined traffic on your network
125 Mbps of traffic on each
100Base-X interface !!!!!!
125 Mbps of
traffic
125 Mbps of
traffic
100Base-T
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iMPathN e t w o r k s
Why use IGMP?
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
On a 100 Mbps interface (optics or electrical) you
cannot pass more then 100 Mbps of traffic.
PROBLEMCombined 125 Mbps of traffic
on these interfaces.
The capacity of this network is
exceeded with only 25 cameras
In fact a typical recommendation in the
industry is not to exceed 70% of the bandwidth
in any segment.
For example:
With 25 cameras deployed,each transmitting at 5 Mbps,
you will have over 125 Mbps of traffic
on your network
100Base-T 100Base-T100Base-T
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iMPathN e t w o r k s
Traffic flow with IGMP
Decoder
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Decoder
L2 Switch
Decoder
Decoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 2Control Center # 1Typical field encoder collector network
100Base-T 100 Meg
Only 15 Mbps of multicast
traffic flows on this link
Only 5 Mbps of
Multicast traffic
Flows on thisport
Traffic is only present on the backbone when a
decoder requests the specific encoder stream
Video Stream 1
Video Stream 2
Video Stream 3
Video Stream 3
100Base-T
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iMPathN e t w o r k s
How does it work?
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L3 Switch/Router L3 Switch/Router L3 Switch/Router L3 Switch/Router
L3 Switch/Router L3 Switch/Router
Encoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 1Typical field encoder collector network
100 Meg
The Encoder is considered a
server in the IGMP world. It
generates a video signal that will
be made available to any
Decoder (client) on the network.
The Encoder transmits a signal with
a distinct destination address.
Between 224.x.x.x to 239.x.x.x.
(some addresses are reserved for
specific applications)
The Routers build and share a
table of all the IGMP serversavailable on the network. They
keep a table of all the available
Multicast Addresses
This Router will not forward
any of the multicast trafficuntil it receives a request
from a decoder (client)
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iMPathN e t w o r k s
Here is how it works -Joining a Group
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L3 Switch/Router L3 Switch/Router L3 Switch/Router L3 Switch/Router
L3 Switch/Router L3 Switch/Router
Encoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 1Typical field encoder collector network
100 Meg
The operator makes a request to see
a video on a specific monitor
The Virtual Matrix application forwards a message to
the decoder to view a specific video stream. (request
to see video from address 224.168.32.55)
The Decoder registers this address in its table and
forwards the request (join the multicast group) to the
network
The Router responds and forwards the traffic to this
specific port on the Ethernet switch.
224.168.32.55
1
2
3
4
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iMPathN e t w o r k s
Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet...
L3 Switch/Router L3 Switch/Router L3 Switch/Router L3 Switch/Router
L3 Switch/Router L3 Switch/Router
Encoder
Decoder
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 1Typical field encoder collector network
100 Meg
When the operator makes a request
to change the view from video A tovideo B
the Virtual Matrix application ONLY forwards a
single message to the decoder to view video B stream.
(request to see video from address 224.168.32.107)
The Decoder un-registers from the present viewing
address (a leave message is sent) followed by
a join message which is sent with the new multicast
stream.
Encoder
Video AVideo B
224.168.32.55224.168.32.107
The Router stops video stream A, adds the new video
B to the group, and releases the traffic for video B to
this specific port on the Ethernet switch.
1
2
3
4
Here is how it works -Leaving a Group
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iMPathN e t w o r k s
Choosing your network elements
There are several types of digital network technologies to choose
from.
SONET and ATM are still applicable but are now rarely
deployed on new installations.
Ethernet is the most common technology due to the widerange of affordable products available from many
manufacturers and the familiarity with Ethernet and IP
technology.
The components more commonly used to build Ethernet
networks are Ethernet Switches.
A high capacity Ethernet network is often referred to as the
backbone network.
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iMPathN e t w o r k s
Choosing your network switches
Choosing Ethernet Switches for your backbone network could
depend on several factors
Your specific port density requirements
Network topology
Temperature hardened requirements (outdoor) Support for IGMP protocol
Your preferred manufacturer
Specific product functionality
This tutorial will explore a few topologies and the IGMP
functionality of different Ethernet Switches.
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iMPathN e t w o r k s
Ethernet Switch selection
There are 3 types of Ethernet Switches
Layer 2 Switch
Distributes traffic to each destination using MAC addressing table.
Broadcasts the Multicast traffic across all its ports
There are no Multicast traffic filters with these switches
Layer 2 Switch with IGMP Snooping
Distributes traffic to each destination using MAC addressing table
Provides limited control of Multicast traffic to prevent broadcast of the
traffic to all ports.
Layer 3 IGMP master is needed in the network
Layer 3 Switch/Router with IGMP
Distributes traffic to each destination using MAC addressing table.
Distributes traffic to each destination using IP subnet addressing table.
Provides maximum control of Multicast traffic to prevent broadcast ofthe traffic to all ports and all subnet.
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iMPathN e t w o r k s
Layer 2 SwitchFunctionality
L2 Switch
Encoder Encoder Encoder
L2 Switch
Decoder DecoderEncoder
5Mbps
15Mbps
5Mbps
15Mbps
5Mbps
15Mbps
5Mbps
15Mbps
0Mbps
20Mbps
0Mbps
20Mbps
The combined Multicast Traffic is sent to all ports in each Switch
This is a valid network topology for small networks
Ensure no more then 70% of the bandwidth of the lowest negotiated Ethernet
port speed is used. Not to be used with 10 Meg Half Duplex devices.
Bandwidth Restriction applies.
Combined 20 Mbps Multicast Video Traffic
5 Mbps Multicast Video per Encoder
20 Mbps
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iMPathN e t w o r k s
Layer 3 Switch/Router with IGMPFunctionality
L3 Switch
Encoder Encoder Encoder
L3 Switch
Decoder DecoderEncoder
5Meg
5Meg
5Meg
5Meg
5Meg
Multicast traffic is filtered out at each switchOnly the required traffic is transmitted on the network
This is a valid network topology for any network - No topology restrictions
10 Mbps
Deploying a Layer 3 at each collector HUB could be expensive
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
0Mbps
0Mbps
Combined 10 Mbps Multicast Video Traffic
5Mbps
5Mbps
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iMPathN e t w o r k s
Layer 2 & 3 SwitchTypical Topology
Decoder Decoder
0Mbps
5Mbps
0Mbps
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
The L3 Switch controls all
Multicast traffic.
In and out.It eliminates transmitting
the combined multicast
traffic unnecessarily to each
port.
0 Mbps
L3 Switch
The use of L2 Switch in this topology is very common. Multicast traffic is repeated on all ports of the
switch within the segment but traffic from other segments is not seen. Traffic between the segments is
controlled by the L3 switch. Economical and practical solution that is very easy to deploy.
35 Mbps Combined Multicast Video
35 Mbps Combined Multicast Video
5Mbps
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iMPathN e t w o r k s
Layer 2 & 3 SwitchTypical TopologyIndustry concern
Decoder Decoder
0Meg
5Meg
0Meg
5Meg
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
35 Mbps
35 Mbps
0 Mbps L3 Switch
This solution is very effective and greatly simplifies Network Management.
However, it is sometimes necessary to filter IGMP traffic at the edge.Such solutions were previously overlooked for economical reasons.
An economical solution now exist: L2 switch with IGMP Snooping
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iMPathN e t w o r k s
Overview of OSI Model
ApplicationPresentation
Session
Transport
Network
Data Link
Physical
Layer 7.
Layer 6
Layer 5
Layer 4
Layer 3- This layer defines the addressing and routing structure of the
Inter-network
This layer controls the Multicast traffic on the network.
Layer 2- This layer defines the framing, addressing and error control of
Ethernet packets. Port addressing uses MAC address of each
device.
This layer effectively treats Multicast traffic as broadcasttraffic.
Layer 1
Traditionally performed by Routers
Performed by Switches
$$
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iMPathN e t w o r k s
Overview of OSI Model
Network
Data Link
$
$
New product introduced
$Layer 2 with IGMP Snooping- Layer 2 Switches with IGMP Snooping
functionality are now available. Provide all the functionality of a
Layer 2 switch with PARTIAL IGMP support.
This layer provides some Multicast traffic control on thenetwork.
This product can be used instead of expensive Routers
Available with different port densities.
100Base-Fx to Gigabit trunks.Temperature Hardened
Wide choice of manufacturers and products.
Layer 3- This layer defines the addressing and routing structure of theInter-network
This layer controls the Multicast traffic on the network.
Layer 2- This layer defines the framing, addressing and error control of
Ethernet packets. Port addressing uses MAC address of each
device.
This layer effectively treats Multicast traffic as broadcasttraffic.
2 S i h i h G S i
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iMPathN e t w o r k s
Layer 2 Switch with IGMP SnoopingFunctionality
L2 with IGMP Snooping
Encoder Encoder Encoder
L3 Switch
Decoder DecoderEncoder
Valid network topology for any network
No topology restrictions
Local traffic is filtered out at each switch. Eliminates
multicasts traffic to all the ports
All the multicast traffic is sent to the central site. The L3
switch still controls the IGMP table of the network.
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
5Mbps
0Mbps
20 Mbps Combined Multicast Video
L2 i h S i & L3 S i h
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iMPathN e t w o r k s
L2 with Snooping & L3 SwitchTypical Topology
Decoder Decoder
0Mbps
5Mbps
0Mbps
5Mbps
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
These links contain the
combined Multicast traffic
from all the Encoders in
their segment i.e. 35 Mbps.
L3 Switch
Very practical implementation
Management of the Ethernet Switches is required.
Switches with IGMP Snooping
eliminate flooding local interfaces
with Multicast traffic.
Bandwidth Restriction applies. No more 70% of link capacity
35 Mbps
35 Mbps
H d i k?
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iMPathN e t w o r k s
How does it work?From the Encoder to the L3 Switch
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
The L3 Switch forwardsthe IGMP Query on all its
ports to determine if there
are any devices that wish
to subscribe to a Multicast
Group.
0 Mbps L3 Switch
Each Encoder forwards a
constant Multicast stream
to the Ethernet Switch
(224-239.x.x.x)
The L2 Switch
detects/identifies the
Multicast stream source
and logs internally what
port this stream came
from.
The L2 Switch with IGMP
Snooping detects the
Query message from the
L3 Switch and logs
internally the ports that
pass traffic to the L3
Switch
L2 Switch eliminates
flooding of the local
interfaces and passes the
Multicast traffic to the L3
Switch for processing.
0Mbps
5Mbps
35 Mbps
H d i k?
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iMPathN e t w o r k s
How does it work?From the Encoder to the L3 Switch
Decoder
0Mbps
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
The L3 Switch detects the
Multicast traffic arriving on this
interface and logs internally all the
Multicast address for distribution.
0 Mbps
L3 Switch
At this point, the Multicast
traffic from all Encoders iscombined on this link
towards the L3 Switch.35 Mbps Combined Multicast Traffic
5Mbps
H d it k?
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iMPathN e t w o r k s
How does it work?From the L3 Switch to the Decoder
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
0 Meg L3 Switch
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 1
The operator makes a request to see
a video on a specific monitor
The Virtual Matrix application forwards a
message to the decoder to view a specific
video stream on a specific monitor. (request
to see video from address 224.168.32.55)
The Decoder registers this address in its table and
forwards the request (join the multicast group) to
the network
The L3 Switch responds and releases the traffic to thisspecific port on the Ethernet switch.
35 Mbps Combined Multicast Traffic
0Mbps
5Mbps
H d it k?
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iMPathN e t w o r k s
How does it work?From the L3 Switch to the Decoder
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
35 Mbps
0 Meg L3 Switch
Virtual Matrix Control ConsoleDisplays video to monitors
Controls camera PTZ
Control Center # 1
The operator makes a NEW request
to see a video on a specific monitor
The Virtual Matrix application forwards a message to the
decoder to view a specific video stream.
(224.168.32.140)
The Decoder registers this address in its table andforwards two messages to the switch
The L3 Switch responds by stopping the stream
224.168.32.55
The Decoder sends an IGMP leave message.
No longer need to receive the Multicast steam
(224.168.32.55)
The Decoder sends an IGMP
request to join
(224.168.32.140)
The L3 Switch responds by forwarding the stream
224.168.32.140
0Mbps
5Mbps
H d it k?
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iMPathN e t w o r k s
How does it work?Typical Star Topology
Decoders
L3 Switch
Multicast traffic flows
from all Encoders to the
L3 Switch
L3 Switch controls the distribution of all Multicast
traffic to Decoders
Encoder
L2 Switch with
IGMP Snooping
W t h f
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iMPathN e t w o r k s
Watch forLimitations of IGMP Snooping
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L3 Switch
L2 Switches with IGMP Snooping have limitations.
In the event of a communication
break between the L2 and L3switches, the L2 IGMP Snooping
switch will behave like a L2 switch
A few minutes after loss of signal, the
switches may* flood all Multicast signals
to the ports of every switch
* Behavior may differ depending on switch manufacturer.
If this is a Gig E link and you have
more then 70 Meg of Video traffic, noother application will run on this
network until the link is re-established.
Maximum port traffic will be exceeded.
W t h f
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iMPathN e t w o r k s
Watch forDistributed Control Centers
L2 Snooping
Encoder
L3 Switch
Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
Multicast traffic flows to the L3 Switch
Multicast join
request sent to the L3
Switch
This switch will allow traffic from
network A to flow to the Decoder when a
join request is received.
Video Source A
Network
A
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iMPathN e t w o r k s
Watch forDistributed Control Centers
L2 Snooping
Encoder
L3 Switch
Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
This switch requires connectivity to the
L3 switch to provide local join
It will not be possible to view
any video. Not even local video.
Communication break
This limitation can be eliminated by installing an L3 Switch at all Control Centers.
Video Source A
Network
A
W t h f
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iMPathN e t w o r k s
Watch forDistributed Control Centers
L2 Snooping
Encoder
L3 Switch
Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
L2 Snooping
EncoderEncoder
All Multicast traffic will flow to the L3 SwitchMulticast traffic flows to the L3 Switch
This switch will only forward traffic
from video source B when the
Decoder requests to join a video from
source B
Multicast join requests are sent to the L3
Switch
Video Source A Video Source B
Configuration Tips
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iMPathN e t w o r k s
Configuration TipsL2 Switch with IGMP Snooping
L2 Snooping
Encoder
L3 Switch
Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
L2 Snooping
EncoderEncoder
Two IGMP configuration modes can be
set in the switches.
Passive Passive Passive
This switch generates IGMP
Queries. It is considered as theMaster or the Active device
In this topology, there can only be one Master unit.
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iMPathN e t w o r k s
Configuration TipsL2 Switch with IGMP Snooping
L2 Snooping
Encoder Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
L2 Snooping
EncoderEncoder
Some L2 Switches with IGMP Snooping can beconfigured as Passive or Active
Passive Passive Passive
This switch generates IGMP
Queries. It is considered as theMaster or the Active
device
In this topology, there can only
be one Master unit.
L2 Snooping
This topology should only be considered for small networks.Most L2 IGMP Snooping Switches do not have the capacity to handle
a large table of IGMP Multicast traffic.
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iMPathN e t w o r k s
Multi-Vendor SupportAvoidMixing IGMP Snooping Switches
L2 Snooping
Encoder Decoder DecoderEncoder
L2 Snooping
Control Center # 2
Decoder Decoder
Control Center # 1
L2 Snooping
EncoderEncoder
Passive Passive Passive
L2 Snooping
Although some L2 IGMP Snooping Switch manufacturers may imply that
they can integrate into a multi-vendor solution, this is not recommended since
IGMP Snooping is not an RFC standard. Implementation differs between
manufacturers. (Proven to fail in our labs)
Active
Manufacturer A Manufacturer A Manufacturer B Manufacturer B
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iMPathN e t w o r k s
Multi-Vendor SupportRecommendation
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L3 Switch
High end products should be used
for L3 Switch to control all your
Multicast traffic. Products from
Foundry, Extreme, Nortel and
Cisco (to name just a few) shouldbe used.
These are typically non-hardened
products
Use L2 with IGMP
SnoopingHardened products
are available
Keep it simple.A single manufacturer
solution is recommended
Several vendorsoffer a wide range ofproducts for this application. Several
(including Magnum 6Ks fromGarrettCom) were tested at iMPath with
positive results.
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iMPathN e t w o r k s
Multi-Vendor SupportAvoid
Decoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L2 Switch
Encoder
L3 Switch
Do not MIXdifferent vendors
IGMP Snooping
switches in this
topology. It will
most-likely notwork
Manufacturer A
Manufacturer A
Manufacturer A
Manufacturer A
Manufacturer A
Manufacturer B
Manufacturer B
Although some L2 IGMP Snooping Switch vendorsmay suggest they can integrate into a multi-vendor
solution, this is not recommended since IGMPSnooping is not a RFC standard. Implementation
differs between manufacturers. (Proven to fail in ourlabs)
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iMPathN e t w o r k s
Manufacturer B
Manufacturer C
Manufacturer A
Manufacturer A
Manufacturer B
Manufacturer C
Multi-Vendor SupportRecommendation
Decoder
L3 Switch
When multi-vendor solutions are used, it is recommended to use a single manufacturer solution on each link. Use
the L3 Switch to separate each group (manufacturer) of L2 IGMP switches.This is the most reliable topology to support multi-vendor solutions.