This document provides an overview of how IGMP (Internet Group Management Protocol) works in digital multicast networks. IGMP allows devices like decoders to join and leave multicast groups to receive video streams from encoders. Without IGMP, multicast traffic would flood the entire network. IGMP optimizes bandwidth usage by only sending multicast streams to ports where decoders have requested them.

1. Multicast Solution How does it work ? Hit left mouse key, the Enter key or Page Up or Down to advance to the next slide July 2005 version 3

2. 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 is any 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 i MPath Networks Inc Tel: 613-226-4000 x 297 Email: dbrisson@impathnetworks.com Gilles Lebel Sr. System Engineer i MPath Networks Inc Tel: 613-226-4000 x 224 Email: glebel@impathnetworks.com

3. Typical Network Requirements Monitor any video from anywhere in the network Backbone

4. 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 amount of 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.

5. Typical Network Components 100 Meg 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 Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical 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 Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

6. Typical Network Components 100 Meg 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 Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical field encoder collector network The Control Centers provide video viewing and control of the Camera PTZ, Traffic Controllers, or Message signs to name just a few. 100 Meg 100 Meg Multiple Control Centers may be deployed with this architecture. The Virtual Matrix is commonly used in digital video networks providing video display and control and to operate complementary integrated applications. Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

7. Why use IGMP? 100 Meg Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet... Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical 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. Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

8. Why use IGMP? 100Base-T Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet... Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical 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 Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

9. Why use IGMP? Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet... Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical field encoder collector network On a 100 Mbps interface (optics or electrical) you cannot pass more then 100 Mbps of traffic. PROBLEM Combined 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-T 100Base-T Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

10. Traffic flow with IGMP Digital Backbone; ATM, SONET, LAN, Gigabit Ethernet... Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 2 Control Center # 1 Typical 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 this port 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 Decoder 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 Decoder L2 Switch Decoder Decoder Decoder

11. 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 Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 1 Typical 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 servers” available on the network. They keep a table of all the available Multicast Addresses This Router will not forward any of the multicast traffic until it receives a request from a decoder (client) Decoder

12. 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 Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 1 Typical 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 Decoder

13. Here is how it works - Leaving 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 Virtual Matrix Control Console Displays video to monitors Controls camera PTZ Control Center # 1 Typical field encoder collector network 100 Meg When the operator makes a request to change the view from video A to video 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 A Video B 224.168.32.55 224.168.32.107 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 Decoder

14. 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 wide range 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.

15. 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.

16. 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 of the traffic to all ports and all subnet.

17. Layer 2 Switch Functionality L2 Switch L2 Switch Decoder Decoder 5 Mbps 15 Mbps 5 Mbps 15 Mbps 5 Mbps 15 Mbps 5 Mbps 15 Mbps 0 Mbps 20 Mbps 0 Mbps 20 Mbps 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. 5 Mbps Multicast Video per Encoder 20 Mbps Encoder Encoder Encoder Encoder Combined 20 Mbps Multicast Video Traffic

18. Layer 3 Switch/Router with IGMP Functionality L3 Switch L3 Switch Decoder Decoder 5 Meg 5 Meg 5 Meg 5 Meg 5 Meg Multicast traffic is filtered out at each switch Only 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 5 Mbps 0 Mbps 5 Mbps 0 Mbps 5 Mbps 0 Mbps 5 Mbps 0 Mbps 0 Mbps 0 Mbps 5 Mbps 5 Mbps Encoder Encoder Encoder Encoder Combined 10 Mbps Multicast Video Traffic

19. Layer 2 & 3 Switch Typical Topology Decoder Decoder 0 Mbps 0 Mbps 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 5 Mbps 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 5 Mbps

20. Layer 2 & 3 Switch Typical Topology – Industry concern Decoder Decoder 0 Meg 5 Meg 0 Meg 5 Meg 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 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

21. Overview of OSI Model Application Presentation 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 broadcast traffic. Layer 1 Traditionally performed by Routers Performed by Switches $ $

22. 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 the network. 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 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 broadcast traffic.

23. Layer 2 Switch with IGMP Snooping Functionality L2 with IGMP Snooping L3 Switch Decoder Decoder 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. 5 Mbps 0 Mbps 5 Mbps 0 Mbps 20 Mbps Combined Multicast Video Encoder Encoder Encoder Encoder 5 Mbps 0 Mbps 5 Mbps 0 Mbps 5 Mbps 0 Mbps 5 Mbps 0 Mbps

24. L2 with Snooping & L3 Switch Typical Topology Decoder Decoder 0 Mbps 5 Mbps 0 Mbps 5 Mbps 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

25. 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 forwards the 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. 0 Mbps 5 Mbps 35 Mbps

26. How does it work? From the Encoder to the L3 Switch Decoder 0 Mbps 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 is combined on this link towards the L3 Switch. 35 Mbps Combined Multicast Traffic 5 Mbps

27. 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 Console Displays 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 this specific port on the Ethernet switch. 35 Mbps Combined Multicast Traffic 0 Mbps 5 Mbps

28. 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 Console Displays 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 and forwards 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 0 Mbps 5 Mbps

29. How does it work? Typical Star Topology Decoders 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 L3 Switch

30. Watch for… Limitations 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 L3 switches, 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, no other application will run on this network until the link is re-established. Maximum port traffic will be exceeded.

31. Watch for… Distributed Control Centers Decoder Decoder 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 L2 Snooping Encoder L3 Switch Encoder L2 Snooping

32. Watch for… Distributed Control Centers Decoder Decoder 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 L2 Snooping Encoder L3 Switch Encoder L2 Snooping

33. Watch for… Distributed Control Centers Decoder Decoder Control Center # 2 Decoder Decoder Control Center # 1 Video Source A Video Source B L2 Snooping Encoder L3 Switch Encoder L2 Snooping L2 Snooping Encoder Encoder All Multicast traffic will flow to the L3 Switch Multicast 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

34. Configuration Tips L2 Switch with IGMP Snooping Decoder Decoder Control Center # 2 Decoder Decoder Control Center # 1 Two IGMP configuration modes can be set in the switches. Passive Passive Passive This switch generates IGMP Queries. It is considered as the “Master” or the “Active” device In this topology, there can only be one Master unit. L2 Snooping Encoder L3 Switch Encoder L2 Snooping L2 Snooping Encoder Encoder

35. Configuration Tips L2 Switch with IGMP Snooping Decoder Decoder Control Center # 2 Decoder Decoder Control Center # 1 Some L2 Switches with IGMP Snooping can be configured as Passive or Active Passive Passive Passive This switch generates IGMP Queries. It is considered as the “Master” or the “Active” device In this topology, there can only be one Master unit. 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. L2 Snooping Encoder Encoder L2 Snooping L2 Snooping Encoder Encoder L2 Snooping

36. Multi-Vendor Support Avoid…Mixing IGMP Snooping Switches Decoder Decoder Control Center # 2 Decoder Decoder Control Center # 1 Passive Passive Passive 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 L2 Snooping Encoder Encoder L2 Snooping L2 Snooping Encoder Encoder L2 Snooping

37. Multi-Vendor Support Recommendation … Decoder 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) should be used. These are typically non-hardened products Use L2 with IGMP Snooping “ Hardened” products are available Keep it simple. A single manufacturer solution is recommended Several vendors offer a wide range of products for this application. Several (including Magnum 6Ks from GarrettCom) were tested at iMPath with positive results. L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder

38. Multi-Vendor Support Avoid… Decoder L3 Switch Do not MIX different vendors IGMP Snooping switches in this topology. It will most-likely not work Manufacturer A Manufacturer A Manufacturer A Manufacturer A Manufacturer A Manufacturer B Manufacturer B Although some L2 IGMP Snooping Switch vendors may suggest they can integrate into a multi-vendor solution, this is not recommended since IGMP Snooping is not a RFC standard. Implementation differs between manufacturers. (Proven to fail in our labs) L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder L2 Switch Encoder

39. Multi-Vendor Support Recommendation… Decoder 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. Manufacturer B Manufacturer C Manufacturer A Manufacturer A Manufacturer B Manufacturer C L3 Switch

40. Credits The information shared in this document was obtained by performing numerous IGMP related tests at iMPath facilities between January and June 2005. Tests were performed using L2, L2 IGMP Snooping, and L3 switches. Over 30 MPEG-2 iMPath Encoders were used during these tests to validate the proper function and performance of the switches under stress. iMPath would like to thank its business partners for their participations and providing equipment and support during the research phase. L2 IGMP Snooping switch manufacturers GarrettCom, as well as Etherwan, IFS, Ruggedcom L3 switch manufacturer Foundry Networks Test Coordinator iMPath Networks, Daniel Brisson, Sr. System Engineer