p2p content distribution for multimedia services in ims-based telco environments
DESCRIPTION
P2P Content Distribution for Multimedia Services in IMS-based Telco Environments. Alex Bikfalvi , Jaime Garcia, Ivan Vidal, Francisco Valera. Overview: P2P and IMS?. Multimedia Services. Peer-to-peer Technologies … what is P2P (very brief)? … why P2P? … what content ? … how ?. - PowerPoint PPT PresentationTRANSCRIPT
P2P Content Distribution forMultimedia Services inIMS-based Telco EnvironmentsAlex Bikfalvi, Jaime Garcia, Ivan Vidal, Francisco Valera
2
Overview: P2P and IMS?
Peer-to-peer Technologies
… what is P2P (very brief)?… why P2P?… what content?… how?
Next Generation Networks
… IMS & NGN?… what is NGN/IMS?… why IMS?… how?
February 3, 2009
Multimedia Services
Does make sense combining P2P and NGN (IMS) technologies?
How can we do this?What services can benefit from P2P content
distribution?What are the advantages for the telcos? But for the
users?
3
Outline
(I) Multimedia services in today’s Internet(II) IMS – a multimedia service platform(III) P2P for multimedia content(IV) A content distribution service for IMSFebruary 3,
2009
4
Part I: Multimedia ServicesMultimedia services in today’s Internet
February 3, 2009
5
The Internet... in 2004P2P traffic was 60% and rising
ISPs identified P2P as a major challenge in network designIt affects the QoS for all usersMostly, file-sharing: BitTorrent, eDonkey, Kad, Gnutella
February 3, 2009
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
0%10%20%30%40%50%60%70%80%90%
100%
HTTPP2POtherFTPEmail
Source: Cache Logic “P2P in 2005”
6
The Internet… in 2007Lately… the HTTP traffic is gaining the share back
… in terms of percentage of total traffic (not absolute value)
February 3, 2009
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004 200
7
0%10%20%30%40%50%60%70%80%90%
100%
HTTPP2POtherFTPEmail
Source: Magid Media Futures survey
7
The Internet… in 2007 and beyond
More than a third of the HTTP traffic is video streamingYouTube is the most popular; counts for around 20%That’s about 10% of all Internet traffic
February 3, 2009
45%
5%14%
36%
Web Audio Other Video
45%
5%14%
20%
16%
Web Audio OtherYouTube Other Video
Source: Magid Media Futures survey
The (near) future…Internet video, the new broadband “killer” application?More “***Tube” service providers?User generated content and commercial content
8
Video content distributionGrowing user demand
Increases bandwidth costs for the service providersYouTube: ≈ 25 PB / month ≈ 1.2 M$ / month
Increases bandwidth demands for the ISPs
Consequences(Popular) Service providers expect an increase in costs at the same quality of service
Deploying/contracting CDN capacityISPs need to provision new capacity to meet the demand
Only selling capacity is not a good business plan for telcosFebruary 3, 2009
Service Provider
Content Distribution
Network
Internet Service/Access Provider
(Telco)Internet
Service/Access Provider
(Telco)
Internet Service/Access Provider
(Telco)
9
Part II: IMS & NGNIMS as a multimedia service platform for Next Generation Networks
February 3, 2009
10
The next generation…… service oriented architecturesTelco keywords
Triple-play packages: voice & TV & InternetTelcos don’t make most $$$ by selling bandwidthTelcos → intermediary entities for service providers
Convergence: legacy networks → next generation (IP)
February 3, 2009
Service Provider
Telco(Internet Access
Provider) End-User
GSM/3G
PSTNxDSL
CableIP Core Network
PSTN GSM/3G
Common Management & Service & Control
Functions
xDSLCable
11
IP Multimedia SubsystemA platform for IP multimedia services
Initially designed by 3GPP as an evolution of GSM/UMTSCurrently extended to many more access networks
Core of a Next Generation Network (TISPAN)
February 3, 2009
Access Networks
Core Network
Transport Control Functions
IP Multimedia Core Network
Subsystem
Service Providers
Service Layer
Transport Layer
Other Networks
IMS GatewaysLegacy terminals
3GPPterminalsIMS terminals
Telco
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IMS: the basicsFunctional entities connected by standardized interfaces
Main purpose: creation of sessions to multimedia sessionsMost of them handle the signaling not the media
February 3, 2009
Access Networks
Access Networks
Access Networks
Access Networks
Core Network
Transport Layer
Service Layer (IMS)P-CSCF
P-CSCF P-CSCFS-CSCF
I-CSCF
HSS
Service Layer (Applications)
IPTV AS
VoD AS Voice AS
Conferencing AS
UEUE
UEUE
UE
UE
UEUE
UEUE
Call Session Control Functions
User Equipments
ApplicationServers
13
IMS: session signalingIMS uses SIP for session signaling
Like a handshake between parties, before multimedia data can be exchangedIndependent on transport layer (uses URIs to identify resources)
SIP network elementsUser agentsServers: proxies, registrars, redirect servers
In IMS the Call Session Control Functions are SIP servers
Proxy-CSCF: the local proxy server for an User EquipmentInterrogating-CSCF: the role of the registrarServing-CSCF: proxy server performing session control
February 3, 2009
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IMS: session signaling example
A SIP example:
February 3, 2009
atlanta.com10.0.0.1
@ 10.0.0.45
[email protected] @ 130.4.1.45
DNS
biloxi.com130.4.1.1
DNS Query: SRV _sip.biloxi.comDNS Response: 130.4.1.1
INVITE sip:[email protected]
200 OK
200 OK
ACK sip:[email protected]
ACK sip:[email protected]
INVITE sip:[email protected]
Request Message Status
Message
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IMS: session signaling example
Session description protocol (SDP)
February 3, 2009
[email protected] [email protected]
INVITE sip:[email protected]: IP, port, codec
183 Session ProgressSDP: IP, port, codec
INVITE sip:[email protected]: IP, port, codec
183 Session ProgressSDP: IP, port, codec
200 OK
200 OK
ACK sip:[email protected]
ACK sip:[email protected]
Session Negotiation
16
IMS: session signaling example
In IMS each users has a dedicated SIP server:In the access (visited) network: the P-CSCFIn the home network: the S-CSCF
Each network has a I-CSCF (the role of the registrar)
February 3, 2009
visited1.com atlanta.com biloxi.com visited2.com
INVITE INVIT
E INVITE INVIT
E INVITE INVIT
E
200 OK
200 OK
200 OK
200 OK
200 OK
200 OK
UEpcscf.visited1.com
P-CSCF
scscf.atlanta.com
S-CSCF
biloxi.com
I-CSCF
scscf.biloxi.com
S-CSCF
pcscf.visited2.com
P-CSCF
bob@biloxi
UE
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IMS applicationsThe S-CSCF perform service control based on user’s service profileUsed to implement application servers
Example: IPTV application server
February 3, 2009
UEpcscf.atlanta.com
P-CSCF
scscf.atlanta.com
S-CSCF
srv.atlanta.com:5999RTSP/UDP
iptv.atlanta.com
AS
INVITE [email protected] INVITE
INVITE [email protected]
Service Control
183 Session ProgressSDP: srv.atlanta.com:5999RTSP/UDP
183 Session ProgressSDP: srv.atlanta.com:5999RTSP/UDP
183 Session ProgressSDP: srv.atlanta.com:5999RTSP/UDP
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Part III: P2P Multimedia Content DistributionP2P technologies for multimedia contentThe architecture of an IMS content distribution service
February 3, 2009
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Content distribution technologies
What are IMS/NGN advantages?Multiple transport technologiesUse of broadband and quality-of-serviceSeparated service and transport functionsGeneralized mobility
However… media (especially video) streaming is extremely expensive
Applications target a lot of receiversWe need support at the transport layer
What are the options?IP multicastContent distribution networkPeer-to-peer
February 3, 2009
Media Server
IMS Terminals (set-top boxes)
IMS
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Case study: video streaming
What are IMS/NGN advantages?Multiple transport technologiesUse of broadband and quality-of-serviceSeparated service and transport functionsGeneralized mobility
However… media (especially video) streaming is extremely expensive
Applications target a lot of receiversWe need support at the transport layer
What are the options?IP multicastContent distribution networkPeer-to-peer
February 3, 2009
Media Server
IMS Terminals (set-top boxes)
IMS
21
Case study: video streaming
What are IMS/NGN advantages?Multiple transport technologiesUse of broadband and quality-of-serviceSeparated service and transport functionsGeneralized mobility
However… media (especially video) streaming is extremely expensive
Applications target a lot of receiversWe need support at the transport layer
What are the options?IP multicastContent distribution networkPeer-to-peer
February 3, 2009
Media Server
IMS Terminals (set-top boxes)
IMS
22
Case study: video streaming
What are IMS/NGN advantages?Multiple transport technologiesUse of broadband and quality-of-serviceSeparated service and transport functionsGeneralized mobility
However… media (especially video) streaming is extremely expensive
Applications target a lot of receiversWe need support at the transport layer
What are the options?IP multicastContent distribution networkPeer-to-peer
February 3, 2009
Media Server
IMS Terminals (set-top boxes)
IMS
23
P2P issuesP2P looks fine… but:
Peers may have an unpredictable behaviorResources (bandwidth, delay) may not be adequateWe need uplink resources as well
February 3, 2009
Fan-out: 3
Fan-out: 2 Fan-out:
2
However, in NGN/IMS:Some peers may be considered stable (e.g. set-top boxes)Resources are known and reservedOnce reserved, they are guaranteed
24
Trees vs. meshesTrees
Mimic multicastEach peer selects a parent peerThe content/stream can be divided and sent across several trees
MeshesA peer obtains pieces from any available peerThere is not a strict relationship: child-parentInstead peers can collaborate in sharing pieces
February 3, 2009
25
Where P2P?P2P media vs. P2P signaling
Until now we discussed P2P in media plane What is P2P signaling?
Discovery of other peers using a P2P protocolFor trees: a structured protocol (DHT) to find a parentFor meshes: an unstructured protocol to find other peers
With P2P signalingThe functionality is distributedNo need of a central entity
February 3, 2009
26
Part IV: A P2P Content Distribution Service for IMS(work in progress)
February 3, 2009
27
Incentives for P2PIMS network capabilities
Smart IMS devices as peers: residential gateways, set-top boxesTransport: quality of service, resource reservation
Telco policies: using capacity that is physically available but not paid for by the user
AdvantagesAll advantages of IMS: AAA, mobility, QoSPerformance improvement goals
Reduce load on core network / service providerKeep most of the traffic in the access network
The telco controls the networkP2P in a managed environment → optimizations
Business modelService providers → Telco → UsersFebruary 3,
2009
28
Why such a service?Video content may be the new killer app, but…
… other services can benefit from P2P too (conferencing, software distribution)… even video may have different requirements (IPTV ≠ VoD)
Content Distribution Service ProviderIntermediary between the Multimedia Content Service Provider and IMS + transport layerMakes the content distribution transparent for the MCSHides the specifics of the media content to the IMS/transport
February 3, 2009
The Content Distribution Service is intended as an adaptation layer between the multimedia content and the mechanism (P2P or otherwise) used for
content distribution
29
The idea
February 3, 2009
AS AS AS
Multimedia Services
AS
Content Distribution Service
IMS
Transport Network
UE UE UE UE UE UE
30
The idea: IPTV simple example
IPTV clientNeeds the address, port of a host delivering the videoWe call this host the content serving host
February 3, 2009
cds.atlanta.com
AS
UE [email protected] client CDS client
INVITE [email protected]: provider=iptv3, ch=5
connect(ch5)INVITE [email protected]: provider=iptv3, ch=5
183 Session ProgressSDP: peer IP, port, protocol, codec
183 Session ProgressSDP: peer IP, port, protocol, codec 200 OK200 OK
ACK [email protected] ACK
return IP, port, …
31
The infrastructureDifferent topologies for P2P
P2P between UEs (same/different access networks)P2P between Edge Servers/Distribution servers
February 3, 2009
User Equipment (IMS terminals)
IMSAS AS ASMultimedia
Services
AS
Content Distribution Service
P2P
P2P
P2P
P2P
Edge/Distribution Servers
32
Business model
February 3, 2009
Transport Provider
P2P streaming enabled network User-
Network InterfaceSet-topboxes
Users
Trust Relationship Pays for the
services retaining a %
Pay for data transport and third-party services
Third Party Service Providers
IMS CDS Provider
Service Package
r
Telco
33
Case Study: IPTVContent: TV channelsNumber of pieces of content: relatively low (hundreds)
RequirementsAccess time very important (channel switching)Low delay of live content (limited caching)Constant streaming (no interruptions)
Design criteriaP2P signaling not an option: latency too largeFast discovery of the content serving host (centralized, AS-based)The edge server may improve performance – maybe P2P signaling is an option here?
February 3, 2009
34
Case Study: Video-on-Demand
Content: published clips / user generated contentNumber of pieces of content: high (very high)
RequirementsInitial access time not criticalDistributed content: caching/storage part of designConstant streaming after video started
Design criteriaP2P signaling could be essential (a lot of content to index)RedundancyP2P protocol can be optimized (no tit-for-tat)
February 3, 2009
35
…other applicationsOther endeavors … telcos might pursuit
Distributed computingDistributed storageDelay tolerant transfersContent distribution with social networking
February 3, 2009
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Conclusions
February 3, 2009
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ConclusionsP2P content distribution in IMS = P2P in a managed networkDoes it make sense?
Bulk of the Internet traffic: P2P and videoTelcos don’t make money from selling bandwidthIMS/NG is the right platform for telcosP2P in the transport layer could be a cost-effective approachTISPAN began working in this direction (first draft Nov ‘08)
ButAlthough 3GPP is pushing IMS standardization…… deployment in near future is uncertain
February 3, 2009
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