Configuration Guide - IP Multicast

Transcription

1 Configuration Guide - IP Multicast Release: Document Revision: NN A Rev02

2 Release: 5.3 Publication: NN Document Revision: Document status: Standard Document release date: 14 August 2009 Copyright 2009 Nortel Networks All Rights Reserved. Printed in Canada, India, and the United States of America LEGAL NOTICE While the information in this document is believed to be accurate and reliable, except as otherwise expressly agreed to in writing NORTEL PROVIDES THIS DOCUMENT "AS IS" WITHOUT WARRANTY OR CONDITION OF ANY KIND, EITHER EXPRESS OR IMPLIED. The information and/or products described in this document are subject to change without notice. Nortel, the Nortel logo, and the Globemark are trademarks of Nortel Networks. All other trademarks are the property of their respective owners. ATTENTION For information about the safety precautions, read "Safety messages" in this guide. For information about the software license, read "Software license" in this guide.

3 Contents About this document Multicast overview Introduction Background of multicast Advantages and applications of multicast Classification of the multicast model Multicast framework Multicast mechanism Multicast addresses Multicast protocols Forwarding mechanism of multicast Multi-instance multicast Introduction to multi-instance Multi-instance multicast application IGMP configuration Introduction IGMP overview Working mechanism of IGMPv New functions of IGMPv Improved functions of IGMPv SSM mapping Multi-instance IGMP Configuring basic IGMP functions Establishing the configuration task Enabling IP multicast routing Enabling IGMP function Configuring IGMP version Configuring a static IGMP group Configuring an interface to join the range of multicast group Checking the configuration Configuring IGMP message options Issue 5.3 (14 August 2009) Nortel Networks Inc. i

4 2.3.1 Establishing the configuration task Configuring IGMP message options Checking the configuration Configuring IGMP query control Establishing the configuration task Configuring IGMP timers Configuring IGMP query and response Checking the configuration Configuring SSM mapping Establishing the configuration task Enabling static SSM mapping Configuring static SSM mapping policy Checking the configuration Maintaining IGMP Clearing the IGMP group information Resetting the IGMP SSM mapping configuration Debugging IGMP Configuration examples Example of configuring basic IGMP functions Example of configuring SSM mapping functions PIM-DM configuration Introduction PIM-DM overview Principle of PIM-DM PIM-DM mechanism Multi-Instance PIM Configuring basic PIM-DM functions Establishing the configuration task Enabling IP multicast routing Enabling PIM-DM Checking the configuration Controlling the forwarding of multicast source Establishing the configuration task Configuring lifetime of sources Configure source address filtering Checking the configuration Adjusting control parameters of neighbors Establishing the configuration task Configuring control parameters of neighbors Checking the configuration Adjusting control parameters of forwarding ii Nortel Networks Inc. Issue 5.3 (14 August 2009)

5 3.5.1 Establishing the configuration task Configuring control parameters used to maintain the forwarding relationship Configuring control parameters of prune Adjusting specifications of join and prune messages Check the configuration Adjusting control parameters of state-refresh Establishing the configuration task Disabling state-refresh Configuring control parameters of state-refresh Checking the configuration Adjusting control parameters of graft Establishing the configuration task Configuring control parameters of graft Checking the configuration Adjusting control parameters of assert Establishing the configuration task Configuring control parameters of assert Checking the configuration Maintaining PIM Debugging PIM Clearing statistics of PIM control Packets Configuration example PIM-SM configuration Introduction PIM-SM overview PIM-SM principles PIM-SM mechanism PIM-SM BSR administrative domain Mechanism of PIM-SSM Multi-instance PIM References Configuring ASM functions Establishing the configuration task Enabling IP multicast routing Enabling the PIM-SM function Configuring static RP Configuring C-RP Configuring C-BSR Configuring BSR boundary Checking the configuration Configuring SSM functions Issue 5.3 (14 August 2009) Nortel Networks Inc. iii

6 4.3.1 Establishing the configuration task Configuring an address range for a PIM-SSM multicast group Checking the configuration Configuring PIM forwarding source control Establishing the configuration task Configuring the lifetime of the source Configuring source address filtering Checking the configuration Adjusting control parameters of the C-RP and C-BSR Establishing the configuration task Adjusting C-RP parameters Adjusting C-BSR parameters Configuring the range of BSR address Configuring the address range of the valid C-RP Checking the configuration Configuring BSR administrative domain Establishing the configuration task Enabling a BSR administrative domain Configuring the boundary of a BSR administrative domain Adjusting C-BSR parameters Checking the configuration Adjusting the control parameters for establishing neighboring relationships Establishing the configuration task Configuring the control parameters for establishing neighboring relationship Configuring the control parameters to elect the DR Checking the configuration Adjusting the control parameters of source registering Establishing the configuration task Configuring PIM-SM register packet Configuring PIM-SM register suppression Checking the configuration Adjusting the control parameters of forwarding Establishing the configuration task Configuring control parameters to keep the forwarding state Configuring control parameters of pruning Adjusting the size of join and prune messages Checking the configuration Adjusting the control parameters of asserting Establishing the configuration task Configuring control parameters of assert Checking the configuration Configuring SPT switchover iv Nortel Networks Inc. Issue 5.3 (14 August 2009)

7 Establishing the configuration task Configuring parameters of SPT switchover Checking the configuration Maintaining PIM Debugging PIM Clearing statistics of the PIM control packet Configuration examples Example of configuring the ASM model in the single BSR domain Example of configuring an SSM network MSDP configuration Introduction MSDP MSDP peer RPF rule of SA message Interdomain multicast implemented by an MSDP peer Intradomain anycast RP implemented by MSDP peer MSDP of multi-instance References Configuring PIM-SM interdomain multicast Establishing the configuration task Configuring MSDP peers Establishing MSDP peers on BGP and MBGP peers Configuring static RPF peers Checking the configuration Configuring anycast RP in PIM-SM domain Establishing the configuration task Configuring C-RP Configuring a static RP interface Statically configuring RP Advertising RP interface address through a unicast route Configuring MSDP peers Specifying logical RP address for SA message Joining a mesh group Checking the configuration Managing MSDP peer connection Establishing the configuration task Controlling the session between MSDP peers Adjusting the interval for retrying setting up MSDP peer connection Checking the configuration Configuring SA cache Establishing the configuration task Issue 5.3 (14 August 2009) Nortel Networks Inc. v

8 5.5.2 Configuring the maximum number of (S, G) in the cache Disabling SA-cache function Checking the configuration Configuring SA request Establishing the configuration task Configuring sending SA request message on the local router Configuring the filtering rules for receiving SA request messages Check the configuration Transmitting burst multicast data within a domain Establishing the configuration task Configuring an SA message to carry a multicast packet Setting the TTL threshold of the multicast packet carried in the SA message Checking the configuration Controlling creation and forwarding of the SA message Establishing the configuration task Controlling the creation of SA Message Controlling the receiving of SA message Controlling the forwarding of SA message Checking the configuration Maintaining MSDP Clearing statistics of MSDP peer Clearing (S, G) information in the SA-cache Debugging MSDP Configuration examples Example of configuring PIM-SM interdomain multicast Example of configuring static RPF peer Example of configuring anycast RP MBGP configuration Introduction Configuring basic MBGP functions Establishing the configuration task Configuring BGP peer Configuring MBGP peer Configuring MBGP route reflector Configuring MBGP to import local routes Checking the configuration Configuring MBGP route advertisement policy Establishing the configuration task Configuring the next hop of the route as local address Configuring the aggregation of local MBGP routes Configuring the local peer to advertise default route vi Nortel Networks Inc. Issue 5.3 (14 August 2009)

9 6.3.5 Configuring the local peer to advertise community attribute Configuring update packets not to carry private AS number Checking the configuration Configuring route exchange policy between MBGP peers Establishing the configuration task Filtering policy of MBGP route exchange Configuring route filtering policy based on route-policy Configuring route filtering policy based on IP ACL Configuring route filtering policy based on AS-path list Configuring route filtering policy based on IP prefix Configuring the maximum number of IP prefixes received from peers Checking the configuration Configuring MBGP route selection policy Establishing the configuration task Setting preferred value of the route learned from peers Configuring MBGP route preference Configuring local-pref of MBGP route Configuring MED attribute of MBGP route Setting dampening parameters of MBGP routes Checking the configuration Maintaining MBGP Debugging MBGP Clearing MBGP statistics Resetting the MBGP connection Example of configuring basic MBGP functions Multicast VPN configuration Introduction Overview of multicast VPN MD VPN over the NORTEL SECURE ROUTER 8000 SERIES Creating Share-MDT Transmission process of the Share-MDT based multicast protocol packet Transmission process of the Share-MDT based multicast data packet Switch-MDT switchover MD VPN across Multi-AS References Configuring MD VPN Establishing the configuration task Enabling IP multicast routing Configuring Share-Group and binding an MTI Setting MTI parameters Checking the configuration Issue 5.3 (14 August 2009) Nortel Networks Inc. vii

10 7.3 Configuring the Switch-MDT switchover Establishing the configuration task Setting switching parameters of Switch-MDT Enabling the log output of Switch-Group reuse Checking the configuration Maintaining MD VPN Configuration examples Example of configuring MD VPN in a single AS Example of configuring inter-as MD VPN Multicast routing and forwarding configuration Introduction Multicast routing and forwarding RPF mechanism Multicast policy Configuring static multicast routes Establishing the configuration task Configuring a static multicast route Checking the configuration Configuring a multicast routing policy Establishing the configuration task Configuring longest match of multicast route Configuring load balancing of multicast route Checking the configuration Configuring multicast forwarding scope Establish the configuration task Configuring multicast forwarding boundary Configuring TTL threshold of multicast forwarding Checking the configuration Setting limitation parameters of multicast forwarding table Establishing the configuration task Setting the maximum number of entries in multicast forwarding table Setting the maximum number of downstream nodes of multicast forwarding entry Checking the configuration Maintaining multicast policy Clearing multicast routing and forwarding entries Debugging multicast routing and forwarding Configuration examples Example of changing RPF routes through static multicast routes Example of connecting RPF routes through static multicast routes Example of implementing multicast through static multicast route tunnel Troubleshooting of static multicast routes viii Nortel Networks Inc. Issue 5.3 (14 August 2009)

11 A Glossary... A-1 B Acronyms and abbreviations...b-1 Index... i-1 Issue 5.3 (14 August 2009) Nortel Networks Inc. ix

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13 Figures Figure 1-1 Unicast transmission Figure 1-2 Broadcast transmission Figure 1-3 Multicast transmission Figure 1-4 Multicast mechanism composition Figure 1-5 Multicast IP address and multicast MAC address Figure 1-6 Application of multicast-related protocols Figure 1-7 VPN networking Figure 2-1 Working mechanism of IGMPv Figure 2-2 Source and group-specific multicast flow path Figure 2-3 SSM mapping networking Figure 2-4 IGMP networking diagram Figure 2-5 SSM mapping networking diagram Figure 3-1 SPT establishment in a PIM-DM domain Figure 3-2 Assert mechanism diagram Figure 3-3 Networking diagram of PIM-DM Figure 4-1 Assert mechanism diagram Figure 4-2 Schematic diagram of DR election Figure 4-3 Communication between C-RP and BSR Figure 4-4 RPT establishment in PIM-SM Figure 4-5 Multicast source registration Figure 4-6 BSR administrative domain (geographical space) Figure 4-7 BSR administrative domain (group address range) Figure 4-8 Schematic diagram of SPT establishment in SSM model Figure 4-9 Typical networking diagram of single BSR domain PIM-DM Figure 5-1 MSDP peers Figure 5-2 MSDP peer connection in mesh group Issue 5.3 (14 August 2009) Nortel Networks Inc. xi

14 Figure 5-3 Cooperation between MSDP and MBGP Figure 5-4 Diagram of MSDP peers Figure 5-5 Anycast RP Figure 5-6 Networking diagram of typical MSDP configuration Figure 5-7 Networking diagram of static RPF peer Figure 5-8 Networking diagram of anycast RP configuration Figure 6-1 MBGP path selection networking diagram Figure 7-1 Typical MPLS/BGP VPN application Figure 7-2 Multicast VPN based on multi-instance Figure 7-3 Diagram of an MD of a VPN instance Figure 7-4 Neighbor relationship between CE, PE, and P in MD scheme Figure 7-5 Diagram of creating Share-MDT in PIM-SM network Figure 7-6 Diagram of creating Share-MDT in PIM-DM network Figure 7-7 Transmission process of multicast packets Figure 7-8 Transmission process of multicast data packets Figure 7-9 VPN instance-to-vpn instance connection method Figure 7-10 Multihop EBGP connection method Figure 7-11 Networking diagram of multicast configuration in BGP MPLS VPN Figure 7-12 Networking diagram of inter-as MD VPN Figure 8-1 Diagram of RPF check process Figure 8-2 Diagram of static multicast route Figure 8-3 Diagram of forwarding multicast packets over a tunnel Figure 8-4 Networking diagram of enabling static multicast route to change RPF route Figure 8-5 Networking diagram of connecting RPF routes through static multicast routes Figure 8-6 Networking diagram of implementing multicast through static multicast route tunnel xii Nortel Networks Inc. Issue 5.3 (14 August 2009)

15 Tables Table 1-1 Common multicast routing issues Table 1-2 Class D address range Table 1-3 Permanent multicast group addresses Table 4-1 D class multicast address range Table 5-1 Configuration solutions of PIM-SM inter-domain multicast Table 5-2 Configuration solution of anycast RP Table 7-1 Configuration information of interfaces Table 7-2 Networking requirements of multicast in MD scheme Table 7-3 Configuration of router interface Table 7-4 Networking requirements of inter-as MD VPN Table 8-1 Description of the display multicast forwarding-table command output Issue 5.3 (14 August 2009) Nortel Networks Inc. xiii

16 Contents About this document...1 Issue 5.3 (14 August 2009) Nortel Networks Inc. i

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18 About this document About this document Overview The document describes the configuration methods of the IP multicast network in terms of basic principles, implementation of protocols, configuration procedures, and configuration examples for the Secure Router 8000 Series. Related versions The following table lists the product versions to which this document relates. Product name Nortel Secure Router 8000 Series Version V200R005 Intended audience The intended audiences of this document are Network operators Network administrators Network maintenance engineers Organization The following table identifies the nine chapters in this document. Chapter Description 1 Multicast overview This chapter describes IP multicast fundamentals, classifications, framework, and the packet forwarding mechanism. 2 IGMP configuration This chapter describes the Internet Group Management Protocol (IGMP) fundamentals, configuration steps, maintenance for IGMP functions, and typical examples. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1

19 About this document Nortel Secure Router 8000 Series Chapter Description 3 PIM-DM configuration This chapter describes the Protocol Independent Multicast Dense Mode (PIM-DM) fundamentals, configuration steps, maintenance for PIM-DM functions, and typical examples. 4 PIM-SM configuration This chapter describes the Protocol Independent Multicast Sparse Mode (PIM-SM) and Source Specific Mode (SSM) fundamentals, configuration steps, maintenance for PIM-SM functions, and typical examples. 5 MSDP configuration This chapter describes the Multicast Source Discovery Protocol (MSDP) fundamentals, configuration steps, maintenance for MSDP functions, and typical examples. 6 MBGP configuration This chapter describes the Multicast Border Gateway Protocol (MBGP) fundamentals, configuration steps, maintenance for MBGP functions, and typical examples. 7 Multicast VPN configuration 8 Multicast routing and forwarding configuration Appendix A Glossary & B Acronyms and Abbreviations Index This chapter describes the multicast virtual private network (VPN) fundamentals, configuration steps, maintenance for multicast VPN functions, and typical examples. This chapter describes the Reverse Path Forwarding (RPF) fundamentals, configuration steps, maintenance for RPF functions, typical examples, and troubleshooting cases. This appendix defines common terms, acronyms, and abbreviations in this document. This chapter provides important keywords in this manual to help you access the required information quickly. Conventions Symbol conventions The following table defines the symbols in this document. Symbol Description Indicates a hazard with a high level of risk that, if you do not avoid, results in death or serious injury. Indicates a hazard with a medium or low level of risk which, if you do not avoid, can result in minor or moderate injury. Indicates a potentially hazardous situation that, if you do not avoid, can cause equipment damage, data loss, and performance degradation or unexpected results. 2 Nortel Networks Inc. Issue 5.3 (14 August 2009)

20 About this document Symbol Description Indicates a tip that can help you solve a problem or save time. Provides additional information to emphasize or supplement important points of the main text. General conventions Convention Times New Roman Boldface Italic Courier New Description Normal paragraphs use Times New Roman. Names of files, directories, folders, and users use boldface. For example, log in as user root. Book titles use italics. Terminal display uses Courier New. Command conventions Convention Boldface Italic Description The keywords of a command line use boldface. Command arguments use italics. [ ] Items (keywords or arguments) in square brackets [ ] are optional. { x y... } Alternative items are grouped in braces and separated by vertical bars. Select one of the items. [ x y... ] Optional alternative items are grouped in square brackets and separated by vertical bars. Select one or none of the items. { x y... } * Alternative items are grouped in braces and separated by vertical bars. Select a minimum of one or a maximum of all of the items. [ x y... ] * &<1-n> Optional alternative items are grouped in square brackets and separated by vertical bars. Select many or none of the items. You can repeat the parameter before the ampersand sign (&) 1 to n times. A line that begins with the number sign () indicates comments. Issue 5.3 (14 August 2009) Nortel Networks Inc. 3

21 About this document Nortel Secure Router 8000 Series GUI conventions Convention Boldface Description Buttons, menus, parameters, tabs, windows, and dialog titles use boldface. For example, click OK. > Multilevel menus use boldface and a greater-than sign (>) separates the menu choices. For example, choose File > Create > Folder. Keyboard operation Format Key Key 1+Key 2 Key 1, Key 2 Description Press the key. For example, press Enter and press Tab. Press the keys concurrently. For example, press Ctrl+Alt+A means you press the three keys at the same time. Press the keys in turn. For example, press Alt, A means you press the two keys one after the other. Mouse operation Action Click Double-click Drag Description Press and release the primary mouse button without moving the pointer. Quickly press the primary mouse button twice without moving the pointer. Press and hold the primary mouse button and move the pointer to a specific position. Update history Updates between document versions are cumulative. The latest document version contains all updates made to previous versions. Updates in Issue 1.0 (6 June 2008) The first commercial release. 4 Nortel Networks Inc. Issue 5.3 (14 August 2009)

22 Contents 1 Multicast overview Introduction Background of multicast Advantages and applications of multicast Classification of the multicast model Multicast framework Multicast mechanism Multicast addresses Multicast protocols Forwarding mechanism of multicast Multi-instance multicast Introduction to multi-instance Multi-instance multicast application Issue 5.3 (14 August 2009) Nortel Networks Inc. i

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24 Figures Figure 1-1 Unicast transmission Figure 1-2 Broadcast transmission Figure 1-3 Multicast transmission Figure 1-4 Multicast mechanism composition Figure 1-5 Multicast IP address and multicast MAC address Figure 1-6 Application of multicast-related protocols Figure 1-7 VPN networking Issue 5.3 (14 August 2009) Nortel Networks Inc. iii

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26 Tables Table 1-1 Common multicast routing issues Table 1-2 Class D address range Table 1-3 Permanent multicast group addresses Issue 5.3 (14 August 2009) Nortel Networks Inc. v

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28 1 Multicast overview 1 Multicast overview About this chapter The following table describes the contents of this chapter. Section Description 1.1 Introduction This section describes the principles and concepts of multicast routing. 1.2 Classification of the multicast model This section describes the classification of the multicast model. 1.3 Multicast framework This section describes the multicast framework. 1.4 Forwarding mechanism of multicast This section describes the forwarding mechanism of multicast. 1.5 Multi-instance multicast This section describes the multi-instance multicast. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-1

29 1 Multicast overview Nortel Secure Router 8000 Series 1.1 Introduction Background of multicast With the fast growth of the Internet, all kinds of interactive data, voice, and video information have also grown. New services such as e-commerce, online conferencing and auctions, video on demand, and e-learning exist. These new technological advances require security, bandwidth, and profit. Modern network transmission technology assigns high importance to the following objectives: Source discovery IP Transmission of Point-to-Multi-Point The following are the solutions to realize the two preceding objectives: Unicast Broadcast Multicast Unicast transmission If you compare the three solutions, you find that multicast is more suitable for the IP transmission of Point-to-Multi-Point. As shown in Figure 1-1, a source exists and User A and User C require the information on the network. The transmission mode is unicast. Figure 1-1 Unicast transmission Source RouterA RouterB RouterC RouterD RouterE RouterF Receiver UserA UserB Receiver UserC packets for UserA packets for UserC The following list summarizes the unicast transmission process: 1-2 Nortel Networks Inc. Issue 5.3 (14 August 2009)

30 1 Multicast overview Broadcast transmission The Source sends separate copy information to each receiver address: packets for User A and packets for User C. The network establishes a separate data transmission path for the each receiver: Source Router B Router E Router D User A; Source Router B Router E Router F User C. In the unicast mode, the relationship between the data that transmits in the network and the users who require the data is in the direct ratio. If many users need the data, many copies of the data flow produce on the network. The bandwidth becomes a key factor to ensure the network transmission quality. The unicast mode is suitable for a network with sparse users but not for the transmission on a large scale. As shown in Figure 1-2, a source exists and User A and User C require the information. The transmission mode is broadcast. Figure 1-2 Broadcast transmission Source RouterA RouterB RouterD RouterE Receiver UserA UserB RouterC RouterF Receiver UserC packets for all the network The following list summaries the broadcast transmission process: The Source sends only one packet to the broadcast address: packets for all the network The network copies the packet and sends it to all the segments, regardless of whether the routers need it: User B also receives the packet In the broadcast mode, all users on the network receive the packet. When there are few users who require packets, the utilization of the network source is quite low and the bandwidth is wasted. This mode affects users who do not need the packet. The broadcast mode is suitable for a network with many users but it does not ensure information security and payment. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-3

31 1 Multicast overview Nortel Secure Router 8000 Series Multicast transmission As shown in Figure 1-3, a source exists and User A and User B require information on the network. The transmission mode is multicast. Figure 1-3 Multicast transmission Source RouterA RouterB RouterD RouterE Receiver UserA UserB RouterC RouterF Receiver UserC packets for the multicast group The following list summarizes the multicast transmission process: Multicast group uses an IP multicast address identifier. User A and User C are members of the multicast group and receive the data sent to the group. The Source sends only one packet to the multicast address: packets for the multicast group. In the process of transmission, the same multicast data flow is present at each link only once. Compared with unicast, the increase of users does not result in an obvious load to the network in the multicast mode. According to the distribution of members, a multicast routing protocol uses tree routing to forward a packet to multiple destinations. The protocol copies the packet, distributes it at a branch as far away as possible, and sends it to receivers. Compared with broadcast, multicast routing sends data to receivers who require it, which saves network resources. The router that supports the multicast function on the network is the multicast router. The multicast router not only provides the multicast routing function, but also manages group members at the leaf segment network that connects with users (like Router D and Router F). At the same time, the router is a member of the multicast group. The members of the group are dynamic and a user host can join and leave the group at any time. Group members can be distributed anywhere on the network. The multicast source does not receive the data it sends; it does not belong to its object multicast group. One source can send data to multiple multicast groups at the same time. Multiple sources can send packets to a multicast group at the same time. As an illustration, compare multicast routing to a TV channel: Multicast routing is the convention between a sender and a receiver; it is like a TV channel. The TV station acts as the multicast router and it sends packets to a channel. 1-4 Nortel Networks Inc. Issue 5.3 (14 August 2009)

32 1 Multicast overview The TV is the receiver host. Audiences turn on the TV and select a program on a channel (hosts join a group). The TV delivers programs of the channel, (hosts receive data sent to the group). Audiences can turn the TV on and off or switch channels randomly, (hosts join or leave a multicast group dynamically) Advantages and applications of multicast Advantages of multicast Applications of multicast The following list identifies the advantages of multicast routing: Enhanced efficiency: reduces network traffic and reduces the load of the server and CPU Optimized performance: decreases traffic redundancy, saves bandwidth, and reduces network load Distributed applications: makes multipoint applications possible IP multicast applies high efficient point-to-multipoint data transmission to IP networks. Multicast saves bandwidth and reduces network load. Multicast supports value-added services, including online broadcasts, network TV, remote education, remote medicine, network TV station, and video and audio conferences. The following list identifies major applications of multicast: Multimedia and streaming media such as live broadcasting, Web TV, real time audio, or video conferencing Communications within the training or co-operating sites like Tele-learning Data storage and finance (stock) applications Application of any point-to-multipoint data distribution like a network radio station 1.2 Classification of the multicast model ASM model Based on the different sources and the destinations, IP multicast divides into the following models: Any-Source Multicast (ASM) Source-Filtered Multicast (SFM) Source-Specific Multicast (SSM) In the ASM model, a sender can act as the multicast source and send information to a multicast group address. Receivers receive all the information sent to the host group by joining the group identified by the address. In the ASM model, receivers do not know the location of the multicast source in advance. The receivers can join or leave the group at any time. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-5

33 1 Multicast overview Nortel Secure Router 8000 Series SFM model The SFM model provides some of the same features as the ASM model. For the sender, the member relationship of the two models is the same. The SFM model extends the ASM model on function: the upper layer software checks the source address of received multicast packets, and permits or denies packets of some multicast sources. The receivers only receive data from partial multicast sources. For the receiver, only partial multicast sources are valid and some multicast sources are filtered. SSM model In practice, users can be interested only in the data sent by certain sources and not need to receive the data sent by other sources. The SSM model provides the kind of transmission service where clients can specify the sources they need. The main difference between the SSM model and the ASM model is that the receivers in the SSM model know the location of the multicast source in advance. The two models use different address scopes. The SSM model establishes a special forwarding path between receivers and the source directly. 1.3 Multicast framework Multicast mechanism Multicast modes are complex and multiple. Multicast modes transmit data from a source to receivers in the multicast mode and meet the different needs of receivers. The following table shows common issues with multicast routing. Table 1-1 Common multicast routing issues Issue To know whether a receiver exists To obtain the multicast information To know where to send the multicast information To forward multicast data Solution Host registration Multicast source discovery technology Multicast addressing mechanism Multicast routing IP multicast is an end-to-end service that consists of four parts as shown in the following figure. 1-6 Nortel Networks Inc. Issue 5.3 (14 August 2009)

34 1 Multicast overview Figure 1-4 Multicast mechanism composition Multicast application Multicast application Multicast routing Multicast routing Host registration Addressing mechanism Host registration Addressing mechanism Host registration Addressing mechanism Host registration Addressing mechanism Multicast source (Host) Multicast router Multicast router Receiver (Host) Addressing mechanism: This function transmits the data from a source to a group of receivers based on the multicast address. Host registration: This function allows the host to dynamically join or leave a group, which helps the host to manage group members. Multicast routing: This function establishes a distribution tree to transmit packets from the source to the receivers. Multicast application: Multicast sources and receivers must support an application, such as video conferencing. The TCP/IP protocol suite must support multicast transmission and reception Multicast addresses IP multicast addresses Multicast transmission involves questions such as where the source sends a packet and how to select the destination address of a multicast packet. These questions involve multicast addressing. Multicast on the network layer enables communication between a source and the receivers across the Internet. Link layer multicast, or hardware multicast, transmits multicast data in the local physical network. When Ethernet applies to the link layer, the hardware multicast uses media access control (MAC) multicast address. You need certain technology to map the IP multicast address to the MAC address. Based on the Internet Assigned Numbers Authority (IANA), the IP address divides into five classes, Class A, B, C, D, and E. The D address identifies the multicast group in a field of the destination address in the IP packet. If the source IP address of IP multicast packets is a unicast address, you can use a Class A, B, or C address. Class D addresses can never be a source IP address. Class E addresses are reserved for future use. On the network layer, an IP group address indentifies all receivers of a multicast group. After a user joins the group, the data sent to the group transmits to the user. The following table shows the Class D multicast address range. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-7

35 1 Multicast overview Nortel Secure Router 8000 Series Table 1-2 Class D address range Class D address range Description to Permanent multicast group addresses to to Temporary multicast group addresses of ASM available in the entire network to Temporary multicast group addresses of SSM available in the entire network to Temporary multicast group addresses of ASM available in local administration domain. The local administration multicast address is a private address. You can use the same address in different multicast administration domains without conflict. Permanent multicast group address: IANA reserves this address for route protocols. This address identifies a group of specific network devices (also called reserved multicast group). For more information, see Table 1-3. The address remains fixed. The number of members is random and can be zero. Temporary multicast group address: This address is assigned for the user group temporarily. If no user exists, the address is cancelled. Table 1-3 Permanent multicast group addresses Permanent multicast group address Description Unassigned Addresses of all hosts and routers in the system Addresses of all multicast routers Unassigned Distance Vector Multicast Routing Protocol routers Open Shortest Path First routers Open Shortest Path First designated routers Internet Stream Protocol (ST) routers ST hosts Routing Information Protocol version 2 routers Mobile agents Dynamic Host Configuration Protocol server or relay agents 1-8 Nortel Networks Inc. Issue 5.3 (14 August 2009)

36 1 Multicast overview Permanent multicast group address Description All Protocol Independent Multicast routers Resource Reservation Protocol encapsulation All core base tree (CBT) routers Designated SBM All SBMS Virtual Router Redundancy Protocol Unassigned Multicast MAC addresses The multicast-mac address identifies receivers of the same multicast group at the link layer. The Ethernet interface board on the network device can identify the multicast-mac address. When you configure a multicast-mac address in the driver, the device can receive and forward data of the multicast group on the Ethernet connection. The IANA specifies the high-order 25 bits of a multicast MAC address as 0x01005e and the low-order 23 bits of a MAC address the same as that of a multicast IP address. The following figure shows the mapping relationship between the multicast IP address and the multicast MAC address. Figure 1-5 Multicast IP address and multicast MAC address 5 bits information loss XXXX X 32 bits IP address 1110 XXXX X XXXXXXX XXXXXXXX XXXXXXXX 48 bits MAC address 23 bits mapping XXXXXXX XXXXXXXX XXXXXXXX 25 bits MAC address prefix The first four bits of the IP multicast address, 1110, are the multicast identifiers. Out of the last 28 bits, only the low-order 23 bits map to the MAC address, which results in the loss of 5 bits of information. 32 IP multicast addresses map to the same MAC addresses. This document focuses on IP multicast technology and device operation. Unless it indicates otherwise, all multicast in the document indicates the IP multicast. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-9

37 1 Multicast overview Nortel Secure Router 8000 Series Multicast protocols Multicast protocols consist of Multicast group management Multicast routing and forwarding The following figure shows the multicast protocol application. Figure 1-6 Application of multicast-related protocols AS1 AS2 User IGMP PIM MBGP /MSDP PIM IGMP Source User Multicast group management protocol Multicast routing protocol The Internet Group Management Protocol (IGMP) runs between the hosts and multicast routers. IGMP defines the mechanism to create and maintain the multicast membership between the multicast routers and the hosts. IGMP has three versions: IGMPv1, IGMPv2, and IGMPv3. Each new version is compatible with the old version. The three versions apply to the ASM model. IGMPv3 can directly apply to the SSM model, while the IGMPv1 and IGMPv2 need SSM-mapping support. The multicast routing protocol runs between routers. The protocol creates and maintains multicast routes, and forwards multicast packets. The multicast route offers a unilateral loop-free transmission path from the source to multiple receivers, a multicast distribution tree. The multicast route in the ASM mode divides into intradomain and interdomain. The intradomain multicast protocols discover multicast sources and establish the multicast distribution tree in the autonomous system (AS) to send data to receivers. PIM is a typical intradomain multicast protocol. The PIM splits into Dense Mode (DM) and Sparse Mode (SM). When receivers are densely distributed in the network, the DM is suitable. When receivers are sparsely distributed in the network, the SM is suitable. The PIM must work with unicast routing protocols Nortel Networks Inc. Issue 5.3 (14 August 2009)

38 1 Multicast overview The intradomain multicast protocol delivers multicast packets among ASs. Multicast Source Discovery Protocol (MSDP) can transmit multicast source information across ASs. The Multicast Border Gateway Protocol (MBGP) of the MultiProtocol BGP (MPBGP) can deliver multicast routes across ASs. In the SSM model, no division of interdomain and intradomain exists. Because receivers know the location of the multicast source in advance, you can create multicast transmission path directly with partial PIM SM functions. 1.4 Forwarding mechanism of multicast In the multicast model, the destination address of an IP packet is the multicast address. The multicast source sends messages to the host groups that the destination address specifies. Unlike the unicast model, to send packets to all receiver hosts, a router on the forwarding path needs to send a packet it receives from an inbound interface to many outbound interfaces. The multicast model is more complex than the unicast model. A multicast routing table such as MBGP guides the forwarding of multicast packets. The mechanism of Reverse Path Forwarding (RPF) ensures that the multicast routing uses a shortest path tree. Most multicast protocols create multicast route entries and forward packets based on the RPF mechanism. For more information about RPF, see Nortel Secure Router 8000 Series Configuration IP Routing (NN ). 1.5 Multi-instance multicast Multi-instance multicast indicates the multicast that applies in the virtual private network (VPN) Introduction to multi-instance The communication between VPNs and between a VPN and a public network must be separate. As shown in the following figure, VPN A and VPN B access the public network using the PE router. Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-11

39 1 Multicast overview Nortel Secure Router 8000 Series Figure 1-7 VPN networking CEb1(2) VPN A CEa2 VPN B PE2 CEb2 CEb1(1) P VPN B CEa1 PE1 Public Network PE3 VPN A CEa3 VPN A P belongs to the public network. Every CE belongs to a VPN. Each router serves only its network and maintains a set of forwarding mechanisms. PE can access the public network and VPN at the same time. The PE serves multiple networks. The network information must be strictly separate and the router maintains a separate set of forwarding mechanisms for each network. The software and hardware devices that serve the same network on the PE are an instance. Multiple instances exist on a PE. One instance distributes on multiple PEs. For more information about multi-instance, see Nortel Secure Router 8000 Series Configuration VPN (NN ) Multi-instance multicast application The Nortel Secure Router 8000 Series product supports multi-instance multicast. The following list identifies the functions you need to apply multi-instance technology to PEs: Maintain a separate set of multicast forwarding mechanism for each instance: The forwarding mechanism supports various multicast protocols and owns a PIM neighbor list and a multicast routing table. Each instance checks its own forwarding table or routing table when it forwards multicast data. Ensure the mutual separation of various instances. Implement the communication of information and data switch between a public network and a VPN instance. Multi-instance multicast is the basis to transmit multicast data across VPNs. The PRODUCT develops multicast VPN technology. Use the VPN A instance in Figure 1-7 as the example in the following illustration of multicast VPN: S belongs to the VPN A and sends data to G. Only members of VPN A can receive the data that S sends Nortel Networks Inc. Issue 5.3 (14 August 2009)

40 1 Multicast overview Multicast data transmits in multicast mode in the VPN A and the public network. For information about multi-instance multicast, see Nortel Secure Router 8000 Series Configuration IP Routing (NN ). Issue 5.3 (14 August 2009) Nortel Networks Inc. 1-13

41 Contents 2 IGMP configuration Introduction IGMP overview Working mechanism of IGMPv New functions of IGMPv Improved functions of IGMPv SSM mapping Multi-instance IGMP Configuring basic IGMP functions Establishing the configuration task Enabling IP multicast routing Enabling IGMP function Configuring IGMP version Configuring a static IGMP group Configuring an interface to join the range of multicast group Checking the configuration Configuring IGMP message options Establishing the configuration task Configuring IGMP message options Checking the configuration Configuring IGMP query control Establishing the configuration task Configuring IGMP timers Configuring IGMP query and response Checking the configuration Configuring SSM mapping Establishing the configuration task Enabling static SSM mapping Configuring static SSM mapping policy Checking the configuration Maintaining IGMP Clearing the IGMP group information Issue 5.3 (14 August 2009) Nortel Networks Inc. i

42 2.6.2 Debugging IGMP Monitoring the Running Status of IGMP Configuration examples Example of configuring basic IGMP functions Example of configuring SSM mapping functions ii Nortel Networks Inc. Issue 5.3 (14 August 2009)

43 Figures Figure 2-1 Working mechanism of IGMPv Figure 2-2 Source and group-specific multicast flow path Figure 2-3 SSM mapping networking Figure 2-4 IGMP networking diagram Figure 2-5 SSM mapping networking diagram Issue 5.3 (14 August 2009) Nortel Networks Inc. iii