International Telecommunication Union
RMCP
(Relayed Multi-Cast
Protocol)
Presented by Juyoung Park
13th October 2005
ITU-T Study Group 17, Geneva, 5-14 October 2005
IF I …
ITU-T
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 !!
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
2
Contents
ITU-T
o Background
o Introduction to RMCP SERIES
o CONCLUSION
o Reference
o Q&A
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
3
We’re on
ITU-T
o Background
• The Best way of Internet Broadcasting service
• Pros and Cons of IP multicast
• ALTERNATIVE WAYS of IP multicast
o Introduction to RMCP SERIES
o CONCLUSION
o Reference
o Q&A
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
4
BACKGROUND
ITU-T
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..
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
5
BACKGROUND
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
6
BACKGROUND
ITU-T
o But, IP MULTICAST needs;
• Enough MONEY
• TECHNICAL Solutions
• Complexity
• Functional limitations
• Limited data delivery service
• DEPLOYMENT
• Timing
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
7
BACKGROUND
ITU-T
o So, WE CANNOT USE IP MULTICAST RIGHT
NOW!
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
8
BACKGROUND
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
9
ALTERNATIVE WAYS OF IP
MULTICAST (1/2)
ITU-T
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.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
10
ALTERNATIVE WAYS OF IP
MULTICAST (2/2)
ITU-T
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.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
11
THE AIM of RMCP
ITU-T
o It has intention to accelerate
“Internet broadcasting services”
on the current Internet.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
12
We’re on
ITU-T
o Background
o 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 interactive
o CONCLUSION
o Reference
o Q&A
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
13
RMCP Motivation (1/3)
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
14
RMCP Motivation (2/3)
ITU-T
o Several mechanisms have been proposed.
• Some mechanisms need special network
devices
• Some mechanisms depend on specific
applications
• No standardization is set
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
15
RMCP Motivation (3/3)
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
16
RMCP
ITU-T
o Goal
• To construct and manage an optimal
relayed multicast data delivery path.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
17
RMCP
ITU-T
o Components
Session Manager
Data Receiver + RMA
Data Sender
+ SMA
Unicast Internet
Data Receiver + RMA
RMCP Data Delivery Path
(when longest path is constructed)
Data Receiver
+ RMA
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
18
RMCP
ITU-T
o What is RMCP?
• RMCP is one of overlay/applicationlayer/relayed multicast protocol.
• RMCP is the first one which follows
international standardization process.
• RMCP consists of 3 separated specification.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
19
RMCP
ITU-T
o 3 separated specification?
• RMCP-1: A framework
• RMCP-2: Specification for SIMPLEX group
applications
• RMCP-3: Specification for N-PLEX group
applications
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
20
RMCP
ITU-T
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~)
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
21
RMCP-1 IN DETAIL
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
22
RMCP-1 IN DETAIL
ITU-T
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.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
23
RMCP-1 IN DETAIL
ITU-T
One-to-many group applications?
Data Sender + SMA
Session Manager
Data Receiver + RMA
MA
Reliable | real-time
uni-directional multicast
MA
Data Receiver + RMA
MA
Data Receiver + RMA
Data Receiver + RMA
RMCP-2
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
24
RMCP-1 IN DETAIL
ITU-T
Many-to-many group applications?
Data Sender/Receiver + SMA
Session Manager
Data Receiver + RMA
MA
Reliable | real-time
bi-directional multicast
Data Sender/Receiver + SMA
MA
MA
Data Receiver + RMA
Data Sender/Receiver + SMA
RMCP-3
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
25
RMCP-1 IN DETAIL
ITU-T
o Relationship among RMCP-series
RMCP-1 : Framework
dates
Real-time
Reliable
1:N
Internet live TV
Internet live concert
File distribution,
stock ticker,
news ticker
RMCP-2
N:N
conference
Network game
RMCP-3
ITU-T Study Group 17, Geneva, 5-14 October 2005
26
RMCP-2 IN BRIEF
ITU-T
dates
o What is RMCP-2
• A real protocol which can manage one-to-many
overlay multicast network (so called overlay
multicast tree)
ITU-T Study Group 17, Geneva, 5-14 October 2005
27
RMCP-2 IN BRIEF
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
28
Control Scheme in RMCP-2 (1/3)
ITU-T
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
session manager
media player
Multicast Area
Multicast Area
Unicast Area
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
MA (Multicast Agent)
29
Control Scheme in RMCP-2 (2/3)
ITU-T
o Control Messages of RMCP (Cont’d)
Operations
Session
Initialization
Tree initialization
Messages
Meaning
From
To
SUBSREQ
Subscription
request
MA
SM
SUBSANS
Subscription
answer
SM
MA
RELREQ
Relay request
CMA
PMA
RELANS
Relay answer
PMA
CMA
LEAVREQ
Leave request
SM/PMA/CMA
MA/CMA/PMA
LEAVANS
Leave answer
MA/CMA/PMA
SM/PMA/CMA
TERMREQ
Termination
request
SM/PMA
SMA/CMA
TERMANS
Termination answer SMA/CMA
Session leave
Session
Termination
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
SM/PMA
30
Control Scheme in RMCP-2 (3/3)
ITU-T
o Message Types
Operations
Messages
Session
Maintenance
HB
Session
Monitoring
Meaning
From
To
Heart beat
SMA/PMA
MA/CMA
STREQ
Status report request
SM
MA
STANS
Status report
MA
SM
PMA
CMA
STCOLREQ
Status
request
collect
STCOLANS
Status collect answer
CMA
PMA
PPROBREQ
Parent probe request
MA
MA
PPROBANS
Parent probe answer
MA
MA
Head solicit
MA
Local Net.
Head announce
HMA
Local Net.
Head leave
HMA
Local Net.
MAP discovery
HSOLICIT
HMA selection
HANNOUNCE
HLEAVE
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
31
RMCP-2 data delivery (1/2)
ITU-T
o Delivering Data
• Media Server (Sender)  SMA (Multicast Agents) : Multicast
• (S)MA  MA : Unicast
• MA  Media Player (Receiver) : Multicast
media server
media player
Multicast Area
unicast tunneling
Unicast Area
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
Multicast Area
MA
: Multicast Agent
32
RMCP-2 data delivery (1/2)
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
MA (Multicast Agent)
33
RMCP-2 IN DETAIL
ITU-T
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.
SM
C
Local network
E
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
WAN
F
G
34
RMCP-2 IN DETAIL
ITU-T
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.
SM
H
C
Local network
D
dates
WAN
E
F
G
ITU-T Study Group 17, Geneva, 5-14 October 2005
35
RMCP-2 IN DETAIL
ITU-T
o Neighbor Discovery (2/2)
• Outside of local broadcast network;
• explore and then measure
o
MA does not have any information on physical
network
G
C
F
C
B
A
A
B
1
1
C
3
dates
A
B
C
E
F
G
2
3
A
B
D
E
G
F
2
D
D
E
A
B
C
E
F
G
F
D
G
D
G
A
B
C
ITU-T Study Group 17, Geneva, 5-14 October 2005
E
F
A
B
C
36
RMCP-2 IN DETAIL
ITU-T
o Tree construction
• Each MAs asks data relay to closest neighbor with
hop-by-hop manner.
RELREQ
RELANS
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
37
RMCP-2 IN DETAIL
ITU-T
o Tree monitoring/maintenance
• A session manager can monitor participants
arbitrarily.
• Each MA can detect and recover network fault by
itself.
STREQ
STREQ
STANS
STANS
dates
SM
ITU-T Study Group 17, Geneva, 5-14 October 2005
38
RMCP-2 IN DETAIL
ITU-T
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.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
39
RMCP-2 Implementation (1/3)
ITU-T
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
40
RMCP-2 Implementation (2/3)
ITU-T
o Demonstration (past)
• Internet Real-time broadcasting on the
APAN (2003.04)
• Internet Real-time broadcasting at the ITUT SG17 meeting (2003.09)
• On going: Regular Test of Internet Realtime streaming video service among ETRI,
CNU, and Kyushu Univ.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
41
RMCP-2 Implementation (3/3)
ITU-T
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
42
RMCP-2 Testbed
ITU-T
SMA
MA
CNU APAN Network
(203.255.248.165/27)
MEDIA SERVER
Kyushu Univ.
APAN Network
(Japan)
SESSION MANAGER
랩톱 컴퓨터
랩톱 컴퓨터
Unicast Router
랩톱 컴퓨터
UNIVERSITY
MEDIA PLAYER(S)
Fast Ethernet
(100M)
CNU
ATM Connection
(155M)
랩톱 컴퓨터
MA
랩톱 컴퓨터
랩톱 컴퓨터
MEDIA PLAYER(S)
ATM Connection
(155M)
Unicast Router
MA
ATM Connection
(155M)
KOREN
ATM Connection
(155M)
Unicast Router
Unicast Router
랩톱 컴퓨터
랩톱 컴퓨터
ATM Connection
(155M)
랩톱 컴퓨터
Unicast Router
랩톱 컴퓨터
랩톱 컴퓨터
MEDIA PLAYER(S)
CNU Campus Network
(168.188.48.1/24)
랩톱 컴퓨터
Candidate Volunteer
from APAN
MEDIA PLAYER(S)
Public Internet
ETRI ATM
ATM Connection
(10M)
MA
Unicast Router
Unicast Router
Ethernet
(10M)
Unicast ROUTER
(Cisco 3640)
MA
Fast Ethernet
(100M)
Fast Ethernet
(100M)
Firewall
Unicast Router
Fast Ethernet
(100M)
?
도시
Geneve
랩톱 컴퓨터
Ethernet
(?)
랩톱 컴퓨터
랩톱 컴퓨터
랩톱 컴퓨터
MEDIA PLAYER(S)
ETRI Public Internet
(129.254.112.1/24)
랩톱 컴퓨터
랩톱 컴퓨터
MEDIA PLAYER(S)
ITU-T Public Internet
(Geneve)
MA
MA
MA
IBM 호환
?
IBM 호환
IBM 호환
IBM 호환
이더넷
이더넷
랩톱 컴퓨터
랩톱 컴퓨터
랩톱 컴퓨터
MEDIA PLAYER(S)
Candidate Volunteer
from Public Internet
dates
IBM 호환
IBM 호환
ETRI APAN Network
(203.255.255.113/29)
IBM 호환
IBM 호환
ETRI APAN Network
(203.255.255.121/29)
ITU-T Study Group 17, Geneva, 5-14 October 2005
43
RMCP-2 Test
ITU-T
WEB SERVER (OF CP)
When
RMCP is
applied to
IPTV alike
service?
MEDIA STREAMING SERVER (OF CP)
Tunneled Streams
Due to RMCP
Original Multicast
Stream From Media
Server
Internet
Live TV
Media
Server
SMA
End-host
Process
DATA Delivery
Path
SESSION MANAGER
Internet
Live TV
Using
RMCP
RMA
Internet
Live TV
Using
RMCP
RMA
Internet
Live TV
Using
RMCP
RMA
dates
ITU-T OF
Study
Group WITH
17, Geneva,
5-14
October
2005
A SERIES
END-HOSTS
INTERNET
LIVE
TV APPLICATION
SUPPORTING RMCP
44
RMCP-3 IN BRIEF
ITU-T
o RMCP-3 is under construction.
• It includes N:N tree construction
mechanism.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
45
We’re on
ITU-T
o Background
o Introduction to RMCP SERIES
o CONCLUSION
o Reference
o Q&A
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
46
CONCLUSION
ITU-T
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.
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
47
CONCLUSION
ITU-T
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!
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
48
We’re on
ITU-T
o Background
o Introduction to RMCP SERIES
o CONCLUSION
o Reference
o Q&A
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
49
References
ITU-T o
o
RMCP Official Home-page, http://ectp.etri.re.kr/
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
dates
ITU-T Study Group 17, Geneva, 5-14 October 2005
50
International Telecommunication Union
Thank you!
Juyoung Park
Senior Researcher/Ph.D
Protocol Engineering Center,
ETRI
jypark@etri.re.kr
http://ectp.etri.re.kr/~jypark
ITU-T Study Group 17, Geneva, 5-14 October 2005