RMCP (Relayed Multi-Cast Protocol)

International Telecommunication Union

ITU-T Study Group 17, Geneva, 5-14 October 2005

RMCPRMCP (Relayed Multi-Cast (Relayed Multi-Cast

Protocol)Protocol)

Presented by Juyoung Park Presented by Juyoung Park 13th October 2005

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IF I …

o If I could have watch 2002 Worldcup soccer games in my office through computer?

o If I can watch a most popular TV drama while I’m in office without TV set?

o DON’T IMAGINE ONLY!USE INTERNET BROADCASTING SERVICE !!

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Contents

o Backgroundo Introduction to RMCP SERIESo CONCLUSIONo Referenceo Q&A

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We’re on

o Background• The Best way of Internet Broadcasting

service• Pros and Cons of IP multicast• ALTERNATIVE WAYS of IP multicast

o Introduction to RMCP SERIESo CONCLUSIONo Referenceo Q&A

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BACKGROUND

o Considerable TWO MAIN CATEGORIES of Internet broadcasting services are;• Internet On-demand Broadcasting

•Internet VoD System•Jukebox

• Internet Live Broadcasting•Internet Live TV (IP TV)•Live Radio Broadcasting•Stock Tickers and so on..

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BACKGROUND

o What is the BEST WAY of supporting Internet Live Broadcasting service?

o The answer would be IP MULTICAST !!• Why?

• It CAN HANDLE hundreds of thousands of SIMULTANEOUS users.

• Because it can;•SAVE network RESOURCES EFFICIENTLY

•REDUCE the load of a sending node’s DRAMATICALLY

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BACKGROUND

o But, IP MULTICAST needs;• Enough MONEY

• TECHNICAL Solutions•Complexity

•Functional limitations

•Limited data delivery service

• DEPLOYMENT•Timing

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BACKGROUND

o So, WE CANNOT USE IP MULTICAST RIGHT NOW!

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BACKGROUND

o Then, is there other way of serving hundreds of thousands of simultaneous connection requests EFFICIENTLY on the Internet?• YES, many efforts to EMULATE IP

MULTICAST!As an ”ALTERNATIVE WAY OF IP MULTICAST”•Replicated IP Unicast•Overlay Multicast

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ALTERNATIVE WAYS OF IP MULTICAST (1/2)

o Replicated Unicast mechanism;• How to?

•A server unicasts to each receivers ITERATIVELY.

• Weak Points•Wasting network resources too much.•Increasing the load of sender drastically.

• Good Points•The EASIST WAY of implementing or deploying service.

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ALTERNATIVE WAYS OF IP MULTICAST (2/2)

o Overlay Multicast mechanism;• How to?

•EACH END HOSTS or SPECIAL DEVICES emulates the IP forwarding mechanism like multicast router.

• Weak Points•End host may face to system or power failures.•So, specially designed mechanism is highly needed

to keep overlay multicast robust.

• Good Points•EASIER WAY of implementing or deploying service.•Efficient Usage of Network resources.

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THE AIM of RMCP

o It has intention to accelerate “Internet broadcasting services” on the current Internet.

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We’re on

o Backgroundo Introduction to RMCP SERIES

• RMCP motivation• RMCP-1 : Framework• RMCP-2 : one-to-many distribution

• Control scheme of RMCP-2• Data delivery scheme of RMCP-2• RMCP-2 testing efforts

• RMCP-3 : many-to-many interactiveo CONCLUSIONo Referenceo Q&A

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RMCP Motivation (1/3)

o Research Motivation• Multicast CAN provides an efficient

delivering mechanism for 1:N or N:N communications

• But, it has not been deployed for the current internet

• So, We need a solution to prompt IP multicast deployment

• Also, End-host and its applications are ready to use IP Multicast

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o Several mechanisms have been proposed.• Some mechanisms need special

network devices• Some mechanisms depend on specific

applications• No standardization is set

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o So, • We want to make an efficient overlay

multicast mechanism.• Which can prompt IP multicast service

right now without changing the Infrastructure of backbone network

• Which follows international standard

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RMCP

o Goal• To construct and manage an optimal

relayed multicast data delivery path.

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RMCP

o Components

RMCP Data Delivery Path(when longest path is constructed)

Session Manager

Data Sender + SMA

Data Receiver + RMA

Data Receiver + RMA

Data Receiver + RMA

Unicast Internet

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RMCP

o What is RMCP?• RMCP is one of overlay/application-

layer/relayed multicast protocol.• RMCP is the first one which follows

international standardization process.• RMCP consists of 3 separated

specification.

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RMCP

o 3 separated specification?• RMCP-1: A framework• RMCP-2: Specification for SIMPLEX

group applications• RMCP-3: Specification for N-PLEX

group applications

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RMCP

o Current State• RMCP-1

• ITU-T Recommendation & ISO IS Finished (’02~`04)

• RMCP-2• ITU-T draft text & ISO CD processing (`03~)• Expecting ITU-T LC procedure in 2006.

• RMCP-3• ITU-T draft text & ISO WD processing (`04~)

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RMCP-1 IN DETAIL

o A framework for Relayed Multi-Cast Protocol• It categorizes present Internet group

services into FOUR. • 1:N real-time data delivery• 1:N reliable data delivery• N:N real-time data delivery• N:N reliable data delivery

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RMCP-1 IN DETAIL

o A framework for Relayed Multi-Cast Protocol• It defines “two possible relayed delivery

path construction” and guides two additional protocols.• 1:N Overlay Multicast Data Delivery (RMCP-2)• N:N Overlay Multicast Data Delivery (RMCP-3)

• It shows a feasible Internet broadcasting service scenario by using RMCP.

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RMCP-2

One-to-many group applications?

RMCP-1 IN DETAIL

Session Manager

MA

Data Receiver + RMAMA

Data Sender + SMA

Data Receiver + RMA

Reliable | real-time uni-directional multicast

MA

Data Receiver + RMA

Data Receiver + RMA

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Session Manager

MA

Data Sender/Receiver + SMA

MA



Reliable | real-time bi-directional multicast

Many-to-many group applications?

RMCP-3

RMCP-1 IN DETAIL

MA

Data Receiver + RMA

Data Receiver + RMA

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RMCP-1 IN DETAIL

o Relationship among RMCP-series

Internet live TVInternet live concert

File distribution,stock ticker,news ticker

conference Network game

Real-time Reliable

1:N

N:N

RMCP-2

RMCP-3

RMCP-1 : Framework

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RMCP-2 IN BRIEF

o What is RMCP-2• A real protocol which can manage one-to-

many overlay multicast network (so called overlay multicast tree)

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RMCP-2 IN BRIEF

o Some noticeable RMCP-2 features are;• 1) Initialization/ Termination

• Bootstrapping• 2) Map discovery

• Inside local broadcast/multicast area• Outside the area

• 3) Late Join / Early Leave • Construct tree automatically

• 4) Maintenance• Status monitoring• Network fault recovery (loop, partition)• Tree improvement

• 5) Data delivery scheme• According to data profile

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Control Scheme in RMCP-2 (1/3)o Exchanging Control Messages

• Media Server SM (unicast) : implicitly• Generic Session Information : Session ID, the preferred

data channel type, etc

• (S)MA SM (unicast) : explicitly• (S)MA MA (unicast) : explicitly

media server media player

Multicast Area

Unicast Area

session manager

Multicast Area

MA (Multicast Agent)

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Control Scheme in RMCP-2 (2/3)

o Control Messages of RMCP (Cont’d)

Operations Messages Meaning From To

Session Initialization

SUBSREQSubscription

requestMA SM

SUBSANSSubscription

answerSM MA

Tree initializationRELREQ Relay request CMA PMA

RELANS Relay answer PMA CMA

Session leaveLEAVREQ Leave request SM/PMA/CMA MA/CMA/PMA

LEAVANS Leave answer MA/CMA/PMA SM/PMA/CMA

Session Termination

TERMREQTermination

requestSM/PMA SMA/CMA

TERMANSTermination

answerSMA/CMA SM/PMA

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Control Scheme in RMCP-2 (3/3)

Operations Messages Meaning From ToSession

MaintenanceHB Heart beat SMA/PMA MA/CMA

Session Monitoring

STREQ Status report request SM MA

STANS Status report MA SM

STCOLREQStatus collect request

PMA CMA

STCOLANS Status collect answer CMA PMA

MAP discoveryPPROBREQ Parent probe request MA MA

PPROBANS Parent probe answer MA MA

HMA selection

HSOLICIT Head solicit MA Local Net.

HANNOUNCE Head announce HMA Local Net.

HLEAVE Head leave HMA Local Net.

o Message Types

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RMCP-2 data delivery (1/2)

o Delivering Data• Media Server (Sender) SMA (Multicast Agents) :

Multicast• (S)MA MA : Unicast• MA Media Player (Receiver) : Multicast

media server media player

unicast tunneling

Multicast Area

MA: Multicast Agent

Multicast Area

Unicast Area

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RMCP-2 data delivery (1/2)

o But RMCP-2 can use any kind of data delivery scheme.• For real-time data delivery

• IP-in-IP, CIPE, UDP tunneling for Real-time data delivery described in Annex B

• For reliable data delivery• TCP tunneling for Reliable data delivery

described in Annex C

MA (Multicast Agent)

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RMCP-2 IN DETAIL

o Bootstrapping• A new joiner don’t know any participated node of the

session.• After successful subscription, SM gives MA list to the

new joiner (MA) as bootstrapping information.• But, each new joiner should explore its network by

itself because SM cannot know the network topology exactly.

WAN

SM

E

Local network

F G

C

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RMCP-2 IN DETAIL

o Neighbor Discovery (1/2)• Inside of local multicast area;

• Sometimes and always, a node in the same network would be the first candidate for its parent.

WAN

SM

C

F GD E

H

Local network

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RMCP-2 IN DETAIL

o Neighbor Discovery (2/2)• Outside of local broadcast network;

• explore and then measureo MA does not have any information on physical

networkA

C

B 1

1

33

D E

22

F

G

ED

A B

C

C

G F

A

E

DB

GF

C

A

E

DB

GF

C

F G

ED

A B C A B C

AB

G F

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RMCP-2 IN DETAIL

o Tree construction• Each MAs asks data relay to closest neighbor

with hop-by-hop manner.

RELREQRELANS

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RMCP-2 IN DETAIL

o Tree monitoring/maintenance• A session manager can monitor participants

arbitrarily.• Each MA can detect and recover network

fault by itself.

STREQ

STANS

SMSTREQ

STANS

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RMCP-2 IN DETAIL

o Tree improvement• Overlay multicast mechanism cannot

guarantee whether the constructed tree is optimized.

• RMCP-2 probes neighbors continuously and switch its parents at need.

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RMCP-2 Implementation (1/3)

o Implemented system• Implemented System Environment:

RedHat 8.0 , C, Gtk+• Implemented components : SM & MA

(2002.06)• Data transmission channel : IP-IP

Tunneling, TCP, UDP

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o Demonstration (past)• Internet Real-time broadcasting on the

APAN (2003.04)• Internet Real-time broadcasting at the

ITU-T SG17 meeting (2003.09)• On going: Regular Test of Internet

Real-time streaming video service among ETRI, CNU, and Kyushu Univ.

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MA MA

Interface

Interface

sm sm

Interface

Interface

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RMCP-2 Testbed

UNIVERSITY

CNU

Unicast Router

Unicast ROUTER(Cisco 3640)

Public Internet

?

?

Geneve

KOREN

IBM 호환

IBM 호환

IBM 호환

IBM 호환

Firewall

도시

Unicast Router

Unicast Router

Unicast Router

Unicast Router

이더넷이더넷

IBM 호환IBM 호환

IBM 호환IBM 호환

ETRI APAN Network(203.255.255.121/29)

CNU Campus Network(168.188.48.1/24)

ITU-T Public Internet(Geneve)

Candidate Volunteerfrom Public Internet

K yushu Univ.APAN Network

(J apan)

Candidate Volunteerfrom APAN

Unicast Router

Unicast Router

ETRI APAN Network(203.255.255.113/29)

ETRI Public Internet(129.254.112.1/24)

Unicast Router

ATM Connection(155M)





ETRI ATM

ATM Connection(10M)

Fast Ethernet(100M)

Fast Ethernet(100M)

Fast Ethernet(100M)

Fast Ethernet(100M)

Ethernet(10M)

Ethernet(?)

CNU APAN Network(203.255.248.165/27)

SMA

SESSION MANAGER

MEDIA SERVER

MA

MA

MAMA

MA

MA

MA

MA

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

랩톱 컴퓨터

MEDIA PLAY ER(S)

랩톱 컴퓨터

랩톱 컴퓨터

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RMA

InternetLive TVUsingRMCP

RMA


RMA


WEB SERVER (OF CP)

End-host

Process

A SERIES OF END-HOSTS WITH INTERNET LIVE TV APPLICATION SUPPORTING RMCP

MEDIA STREAMING SERVER (OF CP)

SESSION MANAGER

DATA DeliveryPath

When RMCP is applied to IPTV alike service?

RMCP-2 Test

SMA

InternetLive TVMediaServer

Original MulticastStream From Media

Server

Tunneled StreamsDue to RMCP

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RMCP-3 IN BRIEF

o RMCP-3 is under construction.• It includes N:N tree construction

mechanism.

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We’re on


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CONCLUSION

o Now, WHAT CAN WE DO with RMCP? (1/2)• EARLY STAGE

• RMCP as an International Standard CAN CATALYZE Internet group service!

• MID STAGE• RMCP CAN act as an INTERIM SOLUTION

for group service during the IP Multicast is being deployed.

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CONCLUSION

o Now, WHAT CAN WE DO with RMCP? (2/2)• LAST STAGE

• RMCP CAN SURVIVE after the IP Multicast is Fully deployed in the next generation network.

o Personal internet live broadcasting services.

o As a solution for Inter-Domain multicast issues.

o For mobile multicast!

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We’re on


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References

o RMCP DOCUMENTS• RMCP-1 Framework,

ITU-T X.603 | ISO/IEC 16512-1• RMCP-2 for Simplex Group Applications,

2nd CD ballot text of ITU-T X.603.1 | ISO/IEC 16512-2• RMCP-3 for N-plex Group Applications,

2nd WD ballot text of ITU-T X.603.2 | ISO/IEC 16512-3

o RMCP Official Home-page, http://ectp.etri.re.kr/

International Telecommunication Union


Thank you!Thank you!Juyoung ParkJuyoung Park

Senior Researcher/Ph.DSenior Researcher/Ph.D

Protocol Engineering Center, Protocol Engineering Center, ETRIETRI

[email protected]@etri.re.kr

http://ectp.etri.re.kr/~jyparkhttp://ectp.etri.re.kr/~jypark

RMCP (Relayed Multi-Cast Protocol)

Documents