Peter Parnes, CDT1 IP-Multicast An Introduction How to solve the “many to many” communication problem? Peter Parnes LTU-CDT/Marratech AB Telia Research AB IP-Multicast An Introduction How to solve the “many to many” communication problem? Peter Parnes LTU-CDT/Marratech AB Telia Research AB

Peter Parnes, CDT2 Overview  Multicasting  MBone  Applications  Conferencing Tools - MBone and mStar  Protocols  MBone and the Internet  Usage  Research issues and further development  Multicasting  MBone  Applications  Conferencing Tools - MBone and mStar  Protocols  MBone and the Internet  Usage  Research issues and further development

Peter Parnes, CDT3 Many to Many  How to implement “many-to-many” traffic? 1. Central server: Have a central server that duplicates packets to all other members. 2. (Fully) connected mesh: Let every member have a connection to all/some other members. 3. Multicasting: Let the network duplicate the packet when needed. 1 and 2 wastes bandwidth!!!!  How to implement “many-to-many” traffic? 1. Central server: Have a central server that duplicates packets to all other members. 2. (Fully) connected mesh: Let every member have a connection to all/some other members. 3. Multicasting: Let the network duplicate the packet when needed. 1 and 2 wastes bandwidth!!!!

Peter Parnes, CDT4 IP Addressing  The TCP/IP family includes four types of distribution of a packet from a single host:  Unicast: To one host  “Normal” IP-traffic  The packet is “seen” only by the receiving host  Broadcast: To all hosts on a network  When trying to find another host  The packet is seen by all hosts on the local network  The TCP/IP family includes four types of distribution of a packet from a single host:  Unicast: To one host  “Normal” IP-traffic  The packet is “seen” only by the receiving host  Broadcast: To all hosts on a network  When trying to find another host  The packet is seen by all hosts on the local network

Peter Parnes, CDT5 IP Addressing  Anycast: To one host of a group of hosts  To access a resource that is served by several computers  IP6  The packet is “seen” by one off the receiving hosts  Multicast: To a group of hosts  The packet is seen by all hosts in the group  The packet is only duplicated when needed  Anycast: To one host of a group of hosts  To access a resource that is served by several computers  IP6  The packet is “seen” by one off the receiving hosts  Multicast: To a group of hosts  The packet is seen by all hosts in the group  The packet is only duplicated when needed

Peter Parnes, CDT6 Multicast vs. Unicast

Peter Parnes, CDT7 Multicasting  Multicast traffic uses a special range of IP-addresses:   A host much join a specific group to receive the traffic in that group but can send to a group without joining.  Membership is controlled by the IGMP protocol.  Multicast traffic uses a special range of IP-addresses:   A host much join a specific group to receive the traffic in that group but can send to a group without joining.  Membership is controlled by the IGMP protocol.

Peter Parnes, CDT8 MBone?  The MBone is both a network-technology and a suite of tools.  The network part is today deployed as a virtual network on the Internet. Sites need to have special MBone-feeds. The setup is handled manually (but only once for each site)  The tools consists today primarily of conferencing tools but more is coming...  The MBone is both a network-technology and a suite of tools.  The network part is today deployed as a virtual network on the Internet. Sites need to have special MBone-feeds. The setup is handled manually (but only once for each site)  The tools consists today primarily of conferencing tools but more is coming...

Peter Parnes, CDT9 Applications  The MBone is today used for:  “Broadcasting”: conferences, meetings, seminars, concerts and radio-stations are multicasted daily.  Conferencing: The MBone is used for traditional video-conferencing (but MUCH cheaper!!)  News: Distribution of Usenet-News  M-FTP: Multi-user File Transfer  The MBone is today used for:  “Broadcasting”: conferences, meetings, seminars, concerts and radio-stations are multicasted daily.  Conferencing: The MBone is used for traditional video-conferencing (but MUCH cheaper!!)  News: Distribution of Usenet-News  M-FTP: Multi-user File Transfer

Peter Parnes, CDT10 Applications Tomorrow  Applications tomorrow include:  Software-distribution: Forget the very costly procedure of new software CDs for each new release and bug-fix! Just supply the latest version in a known multicast- group.  Mirroring: Instead of letting each client fetch all new files from a server, send out the changed files using multicast!  Applications tomorrow include:  Software-distribution: Forget the very costly procedure of new software CDs for each new release and bug-fix! Just supply the latest version in a known multicast- group.  Mirroring: Instead of letting each client fetch all new files from a server, send out the changed files using multicast!

Peter Parnes, CDT11 Applications Tomorrow  Real News: All news is transmitted on the net. Indexed and ready. (Reuters have this since 1996!)  TV: Why not watch your favourite TV- channel over the network?  File-Caches: If all file-requests are issued using multicasting it’s much easier to cache them locally!  And much much much  Real News: All news is transmitted on the net. Indexed and ready. (Reuters have this since 1996!)  TV: Why not watch your favourite TV- channel over the network?  File-Caches: If all file-requests are issued using multicasting it’s much easier to cache them locally!  And much much much

Peter Parnes, CDT12 Conferencing tools  The MBone tools today consists of:  SDR: The session directory, “the channel- guide”  WB: A distributed white-board (postscript and text)  VIC: A video-tool  VAT/RAT: Two audio-tools  mStar!  The MBone tools today consists of:  SDR: The session directory, “the channel- guide”  WB: A distributed white-board (postscript and text)  VIC: A video-tool  VAT/RAT: Two audio-tools  mStar!

Peter Parnes, CDT13 MBone bild extern!  Extern bild!

Peter Parnes, CDT14 The mStar Family  A family of tools for scalable distributed electronic teamwork.  It supports a number of different conferencing media:  audio/video  shared whiteboard, chatting, voting  Web based electronic presentations  A family of tools for scalable distributed electronic teamwork.  It supports a number of different conferencing media:  audio/video  shared whiteboard, chatting, voting  Web based electronic presentations

Peter Parnes, CDT15 multicast Audio: mAudio

Peter Parnes, CDT16 Video - VIC

Peter Parnes, CDT17 multicast Web: mWeb

Peter Parnes, CDT18 multicast WhiteBoard: mWB

Peter Parnes, CDT19 multicast Vote: mVote

Peter Parnes, CDT20 multicast Chat: mChat

Peter Parnes, CDT21 multicast Media On Demand: mMOD  As all traffic is network and multicast based, it is very easy to record it.  mMOD is another member of mStar that support recording and later playback.  Web based control  As all traffic is network and multicast based, it is very easy to record it.  mMOD is another member of mStar that support recording and later playback.  Web based control

Peter Parnes, CDT22 multicast Tunnel: mTunnel  Some links do not support multicast  ISDN, analog modem  mTunnel allows for easy tunnelling of multicast traffic over non-multicast links.  It also allows for traffic transformation:  recoding, mixing, switching, scaling  This allows users to join into high bandwidth sessions even if they do not have the needed bandwidth.  Some links do not support multicast  ISDN, analog modem  mTunnel allows for easy tunnelling of multicast traffic over non-multicast links.  It also allows for traffic transformation:  recoding, mixing, switching, scaling  This allows users to join into high bandwidth sessions even if they do not have the needed bandwidth.

Peter Parnes, CDT23 mStar Design Issues  Scalable: The environment should scale to a very large number of users - IP-Multicast is the solution!  Robust: The environment should survive network failures and not be dependent on any central services  Accessible: Users should be able to participate from their desktop  Network based: No need for any special ISDN connections, just the standard local network and the Internet.  Scalable: The environment should scale to a very large number of users - IP-Multicast is the solution!  Robust: The environment should survive network failures and not be dependent on any central services  Accessible: Users should be able to participate from their desktop  Network based: No need for any special ISDN connections, just the standard local network and the Internet.

Peter Parnes, CDT24 Protocols MANY different protocols involved with Multicasting - UDP, RTP, SRM, MTP-2, MTCP  UDP: User Datagram Protocol  Unreliable == Packets can be lost  The applications has to take care of reliability MANY different protocols involved with Multicasting - UDP, RTP, SRM, MTP-2, MTCP  UDP: User Datagram Protocol  Unreliable == Packets can be lost  The applications has to take care of reliability

Peter Parnes, CDT25 RTP RTP - Real-Time Transfer Protocol  Developed by the IETF (RFC1889/90) and later copied into ITU/H.225.  End-to-End transport functionality for real-time data  Designed for multicasting  Completely network layer independent RTP - Real-Time Transfer Protocol  Developed by the IETF (RFC1889/90) and later copied into ITU/H.225.  End-to-End transport functionality for real-time data  Designed for multicasting  Completely network layer independent

Peter Parnes, CDT26 Reliable Multicasting  No standard today (IETF/ITU are not working on this problem although several other groups are)  Multicast Transport Protocol 2 - MTP2  NACK based  Fanout TCP - MTCP  Star-topology with a TCP connection to each receiver  No standard today (IETF/ITU are not working on this problem although several other groups are)  Multicast Transport Protocol 2 - MTP2  NACK based  Fanout TCP - MTCP  Star-topology with a TCP connection to each receiver

Peter Parnes, CDT27 Reliable Multicasting  Scalable Reliable Multicasting - SRM  NACK based - every member participates in repairs and not only the original sender of a packet  Used in the MBone WB  I have designed a RTP-extension to include SRM.  This is today implemented and used in the mStar WhiteBoard.  Scalable Reliable Multicasting - SRM  NACK based - every member participates in repairs and not only the original sender of a packet  Used in the MBone WB  I have designed a RTP-extension to include SRM.  This is today implemented and used in the mStar WhiteBoard.

Peter Parnes, CDT28 More Protocols  Session Description Protocol - SDP  Session Announcement Protocol - SAP  Real-time Streaming Protocol - RTSP  Session Initiation Protocol - SIP  Receiver-based Layered Multicast - RLM  Plus many more….  Session Description Protocol - SDP  Session Announcement Protocol - SAP  Real-time Streaming Protocol - RTSP  Session Initiation Protocol - SIP  Receiver-based Layered Multicast - RLM  Plus many more….

Peter Parnes, CDT29 MBone and the Internet  To simplify the development process of the MBone-network, it was first deployed as a virtual network using IP-tunnels  but is now changed into a standard IP- service == all routers need to know about multicasting  Multicasting is both an Internet and an Intranet technology  To simplify the development process of the MBone-network, it was first deployed as a virtual network using IP-tunnels  but is now changed into a standard IP- service == all routers need to know about multicasting  Multicasting is both an Internet and an Intranet technology

Peter Parnes, CDT30 Usage Scenarios of mStar  Electronic Meetings  Meeting using your desktop computer  Distance Education  Distribution of lectures over the Internet where participants can ask questions and be active  Electronic Corridor  Daily work where users run the tools 24 hours a day  Electronic Meetings  Meeting using your desktop computer  Distance Education  Distribution of lectures over the Internet where participants can ask questions and be active  Electronic Corridor  Daily work where users run the tools 24 hours a day

Peter Parnes, CDT31 Usage Examples  Education Direct  Distribution of lectures to the county of Norrbotten  Ericsson Erisoft  Electronic meetings and teamwork between their offices and Ericsson in Stockholm and other countries  Daily work at CDT  mStar is used for electronic meetings, the electronic corridor, multicast of seminars and courses  Education Direct  Distribution of lectures to the county of Norrbotten  Ericsson Erisoft  Electronic meetings and teamwork between their offices and Ericsson in Stockholm and other countries  Daily work at CDT  mStar is used for electronic meetings, the electronic corridor, multicast of seminars and courses

Peter Parnes, CDT32 Future Research Issues  Multicast address allocation - MALLOC  Layered encodings for both audio and video  Better bandwidth control (TCP-friendly)  New audio and video encodings that perform better in lossy environments.  H.323/T.120 integration/interoperability  Better security  Multicast address allocation - MALLOC  Layered encodings for both audio and video  Better bandwidth control (TCP-friendly)  New audio and video encodings that perform better in lossy environments.  H.323/T.120 integration/interoperability  Better security

Peter Parnes, CDT33 Further Development of mStar  Marratech AB  Collaboration projects with TRAB  Roxy  MediaSite  Education Direct  CDT Distributed Software Lab - NUTEK  Marratech AB  Collaboration projects with TRAB  Roxy  MediaSite  Education Direct  CDT Distributed Software Lab - NUTEK

Peter Parnes, CDT34 Native Multicast in Sweden  SUNET: The whole network  Telia: Almost working in the county network. Nothing in the rest of the production network  Tele-2: Nothing yet  GlobalOne: Full native multicast support in their backbone network  SUNET: The whole network  Telia: Almost working in the county network. Nothing in the rest of the production network  Tele-2: Nothing yet  GlobalOne: Full native multicast support in their backbone network

Peter Parnes, CDT35 Summary  IP multicast provides a scalable solution for “many-to-many” communication.  A number of tools are being deployed on the Internet today to utilize the power of IP multicast.  mStar being turned into a product.  Native multicast is slowly being deployed around the world.  IP multicast provides a scalable solution for “many-to-many” communication.  A number of tools are being deployed on the Internet today to utilize the power of IP multicast.  mStar being turned into a product.  Native multicast is slowly being deployed around the world.

Peter Parnes, CDT36 Questions?

Peter Parnes, CDT37 Multicasting and FireWalls  Political question NOT technical  There is nothing special about multicasting in comparison to other IP- traffic. There are four solutions to the FireWall problem: 1Open the wall for all multicast-traffic. Simple and a router can control which networks within a company should have MBone access.  Political question NOT technical  There is nothing special about multicasting in comparison to other IP- traffic. There are four solutions to the FireWall problem: 1Open the wall for all multicast-traffic. Simple and a router can control which networks within a company should have MBone access.

Peter Parnes, CDT38 Multicasting and FireWalls 2Set up a tunnel through the wall 3Rent a dedicated line that isn’t connected to the rest of the companies network and is only used for Multicasting 4Stay behind the rest and don’t use multicasting at all! :-) 2Set up a tunnel through the wall 3Rent a dedicated line that isn’t connected to the rest of the companies network and is only used for Multicasting 4Stay behind the rest and don’t use multicasting at all! :-)