peter parnes, marratech/cdt1 ip-multicast and its companions an introduction how to solve the...

Peter Parnes, Marratech/CDT 1

IP-Multicast and its Companions

An IntroductionHow to solve the “many to many”

communication problem?

Peter Parnes

LTU-CDT/Marratech AB

Enator - 990416

IP-Multicast and its Companions

An IntroductionHow to solve the “many to many”

communication problem?

Peter Parnes

LTU-CDT/Marratech AB

Enator - 990416


Overview Multicasting MBone Applications Conferencing Tools - MBone and mPro Protocols MBone and the Internet Usage “Smörgåsbordet”

Multicasting MBone Applications Conferencing Tools - MBone and mPro Protocols MBone and the Internet Usage “Smörgåsbordet”


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!!!!


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


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


Multicast vs. Unicast


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.


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...


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


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!


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.......


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

Marratech Product Suite

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

Marratech Product Suite


The mPro 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


The mFamily history

mStar was developed by CDT since 1995 (CDT created Jan-95) Today about 30 persons

Was used in a number of different scenarios over the years

Marratech AB spring 98 m* -> mStar -> mPro (mFamily)

mStar trademarked by Motorola

mStar was developed by CDT since 1995 (CDT created Jan-95) Today about 30 persons

Was used in a number of different scenarios over the years

Marratech AB spring 98 m* -> mStar -> mPro (mFamily)

mStar trademarked by Motorola


multicast Media Server: mMS

As all traffic is network and multicast based, it is very easy to record it.

mMS is another member of mFamily that support recording and later playback.

Web based control (work in progress)

As all traffic is network and multicast based, it is very easy to record it.

mMS is another member of mFamily that support recording and later playback.

Web based control (work in progress)


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.


mFamily 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.


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


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


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


Reliable Multicast - SRRTP

Scalable Reliable Multicasting - SRM NACK based - every member participates in

repairs and not only the original sender of a packet

Originally used in the MBone WB I have designed a RTP-extension to include

SRM - SRRTP This is today implemented and used in the

mPro family.

Scalable Reliable Multicasting - SRM NACK based - every member participates in

repairs and not only the original sender of a packet

Originally used in the MBone WB I have designed a RTP-extension to include

SRM - SRRTP This is today implemented and used in the

mPro family.


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….


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


Usage Scenarios of the mFamily 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


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 mFamily 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 mFamily is used for electronic meetings, the

electronic corridor, multicast of seminars and courses


“Smörgåsbordet”

Mcast routing, real-time traffic, security, session announcement, session invitation, H.323, mcast address allocation, stream control, better service, codecs and media packetization, congestion control for multimedia

mManagement, mTunnel, scalable media, advanced audio

(The education scenario)

Mcast routing, real-time traffic, security, session announcement, session invitation, H.323, mcast address allocation, stream control, better service, codecs and media packetization, congestion control for multimedia

mManagement, mTunnel, scalable media, advanced audio

(The education scenario)


Questions?

[email protected]

http://www.cdt.luth.se/~peppar/

http://www.cdt.luth.se/mStar/

http://www.marratech.com/

[email protected]

http://www.cdt.luth.se/~peppar/

http://www.cdt.luth.se/mStar/

http://www.marratech.com/


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.


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! :-)

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