Download - IP-Multicast An Introduction How to solve the “many to many” communication problem? Peter Parnes
Peter Parnes, CDT 1
IP-Multicast
An IntroductionHow to solve the “many to many”
communication problem?
Peter Parnes
LTU-CDT/Marratech AB
Telia Research AB - 980827
IP-Multicast
An IntroductionHow to solve the “many to many”
communication problem?
Peter Parnes
LTU-CDT/Marratech AB
Telia Research AB - 980827
Peter Parnes, CDT 2
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, CDT 3
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!!!!
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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
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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, CDT 6
Multicast vs. Unicast
Peter Parnes, CDT 7
Multicasting
Multicast traffic uses a special range of IP-addresses: 224.0.0.0 - 239.255.255.255
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: 224.0.0.0 - 239.255.255.255
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, CDT 8
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...
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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
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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!
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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, CDT 12
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!
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MBone bild extern!
Extern bild! Extern bild!
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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
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multicast Audio: mAudio
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Video - VIC
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multicast Web: mWeb
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multicast WhiteBoard: mWB
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multicast Vote: mVote
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multicast Chat: mChat
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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, CDT 22
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, CDT 23
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, CDT 24
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, CDT 25
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
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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
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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, CDT 28
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, CDT 29
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, CDT 30
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, CDT 31
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, CDT 32
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, CDT 33
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
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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, CDT 35
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, CDT 36
Questions?
http://www.cdt.luth.se/~peppar/
http://www.cdt.luth.se/mStar/
http://www.marratech.com/
http://www.cdt.luth.se/~peppar/
http://www.cdt.luth.se/mStar/
http://www.marratech.com/
Peter Parnes, CDT 37
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:
1 Open 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:
1 Open the wall for all multicast-traffic. Simple and a router can control which networks within a company should have MBone access.
Peter Parnes, CDT 38
Multicasting and FireWalls
2 Set up a tunnel through the wall
3 Rent a dedicated line that isn’t connected to the rest of the companies network and is only used for Multicasting
4 Stay behind the rest and don’t use multicasting at all! :-)
2 Set up a tunnel through the wall
3 Rent a dedicated line that isn’t connected to the rest of the companies network and is only used for Multicasting
4 Stay behind the rest and don’t use multicasting at all! :-)