Ims content distributionnetworks

P2P Content Distribution forMultimedia Services inIMS-based Telco Environments Alex Bikfalvi, Jaime Garcia, Ivan Vidal, Francisco Valera

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 2 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?

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 IMS February 3, 2009 3

Part I: Multimedia Services Multimedia services in today’s Internet February 3, 2009 4

The Internet... in 2004 P2P traffic was 60% and rising ISPs identified P2P as a major challenge in network design It affects the QoS for all users Mostly, file-sharing: BitTorrent, eDonkey, Kad, Gnutella February 3, 2009 5 Source: Cache Logic “P2P in 2005”

The Internet… in 2007 Lately… the HTTP traffic is gaining the share back … in terms of percentage of total traffic (not absolute value) February 3, 2009 6 Source: Magid Media Futures survey

The Internet… in 2007 and beyond More than a third of the HTTP traffic is video streaming YouTube is the most popular; counts for around 20% That’s about 10% of all Internet traffic February 3, 2009 7 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

Video content distribution Growing user demand Increases bandwidth costs for the service providers YouTube: ≈ 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 capacity ISPs need to provision new capacity to meet the demand Only selling capacity is not a good business plan for telcos February 3, 2009 8 Service Provider Content Distribution Network Internet Service/Access Provider (Telco) Internet Service/Access Provider (Telco) Internet Service/Access Provider (Telco)

Part II: IMS & NGN IMS as a multimedia service platform for Next Generation Networks February 3, 2009 9

The next generation… … service oriented architectures Telco keywords Triple-play packages: voice & TV & Internet Telcos don’t make most $$$ by selling bandwidth Telcos -> intermediary entities for service providers Convergence: legacy networks -> next generation (IP) February 3, 2009 10 Telco (Internet Access Provider) End-User Service Provider IP Core Network Common Management & Service & Control Functions xDSL PSTN Cable Cable GSM/3G PSTN xDSL GSM/3G

IP Multimedia Subsystem A platform for IP multimedia services Initially designed by 3GPP as an evolution of GSM/UMTS Currently extended to many more access networks Core of a Next Generation Network (TISPAN) February 3, 2009 11 Service Providers IP Multimedia Core Network Subsystem Service Layer Transport Control Functions Transport Layer IMS Gateways Legacy terminals Other Networks Core Network Access Networks 3GPPterminals IMS terminals Telco

IMS: the basics Functional entities connected by standardized interfaces Main purpose: creation of sessions to multimedia sessions Most of them handle the signaling not the media February 3, 2009 12 Conferencing AS Application Servers IPTV AS Voice AS Service Layer (Applications) VoD AS P-CSCF Call Session Control Functions P-CSCF S-CSCF HSS P-CSCF Service Layer (IMS) I-CSCF UE UE Access Networks Access Networks UE UE User Equipments Core Network UE Access Networks UE Access Networks Transport Layer UE UE UE UE

IMS: session signaling IMS uses SIP for session signaling Like a handshake between parties, before multimedia data can be exchanged Independent on transport layer (uses URIs to identify resources) SIP network elements User agents Servers: proxies, registrars, redirect servers In IMS the Call Session Control Functions are SIP servers Proxy-CSCF: the local proxy server for an User Equipment Interrogating-CSCF: the role of the registrar Serving-CSCF: proxy server performing session control February 3, 2009 13

IMS: session signaling example A SIP example: February 3, 2009 14 alice@atlanta.com @ 10.0.0.45 bob@biloxi.com @ 130.4.1.45 alice@atlanta.com 10.0.0.45 bob@biloxi.com 130.4.1.45 atlanta.com 10.0.0.1 biloxi.com 130.4.1.1 DNS DNS Query: SRV _sip.biloxi.com DNS Response: 130.4.1.1 INVITE sip:bob@biloxi.com INVITE sip:bob@biloxi.com Request Message Status Message 200 OK 200 OK ACK sip:bob@biloxi.com ACK sip:bob@biloxi.com

IMS: session signaling example Session description protocol (SDP) February 3, 2009 15 alice@atlanta.com bob@biloxi.com Session Negotiation INVITE sip:bob@biloxi.com SDP: IP, port, codec INVITE sip:bob@biloxi.com SDP: IP, port, codec 183 Session Progress SDP: IP, port, codec 183 Session Progress SDP: IP, port, codec 200 OK 200 OK ACK sip:bob@biloxi.com ACK sip:bob@biloxi.com

IMS: session signaling example In IMS each users has a dedicated SIP server: In the access (visited) network: the P-CSCF In the home network: the S-CSCF Each network has a I-CSCF (the role of the registrar) February 3, 2009 16 visited1.com atlanta.com biloxi.com visited2.com alice@atlanta.com pcscf.visited1.com scscf.atlanta.com biloxi.com scscf.biloxi.com pcscf.visited2.com bob@biloxi UE P-CSCF S-CSCF I-CSCF S-CSCF P-CSCF UE INVITE INVITE INVITE INVITE INVITE INVITE 200 OK 200 OK 200 OK 200 OK 200 OK 200 OK

IMS applications The S-CSCF perform service control based on user’s service profile Used to implement application servers Example: IPTV application server February 3, 2009 17 srv.atlanta.com:5999 RTSP/UDP alice@atlanta.com pcscf.atlanta.com scscf.atlanta.com iptv.atlanta.com UE P-CSCF S-CSCF AS INVITE iptv@atlanta.com INVITE iptv@atlanta.com INVITE iptv@atlanta.com Service Control 183 Session Progress SDP: srv.atlanta.com:5999 RTSP/UDP 183 Session Progress SDP: srv.atlanta.com:5999 RTSP/UDP 183 Session Progress SDP: srv.atlanta.com:5999 RTSP/UDP

Part III: P2P Multimedia Content Distribution P2P technologies for multimedia content The architecture of an IMS content distribution service February 3, 2009 18

Content distribution technologies What are IMS/NGN advantages? Multiple transport technologies Use of broadband and quality-of-service Separated service and transport functions Generalized mobility However… media (especially video) streaming is extremely expensive Applications target a lot of receivers We need support at the transport layer What are the options? IP multicast Content distribution network Peer-to-peer February 3, 2009 19 Media Server IMS IMS Terminals (set-top boxes)

Case study: video streaming What are IMS/NGN advantages? Multiple transport technologies Use of broadband and quality-of-service Separated service and transport functions Generalized mobility However… media (especially video) streaming is extremely expensive Applications target a lot of receivers We need support at the transport layer What are the options? IP multicast Content distribution network Peer-to-peer February 3, 2009 20 Media Server IMS IMS Terminals (set-top boxes)

P2P issues P2P looks fine… but: Peers may have an unpredictable behavior Resources (bandwidth, delay) may not be adequate We need uplink resources as well February 3, 2009 23 However,in NGN/IMS: Some peers may be considered stable (e.g. set-top boxes) Resources are known and reserved Once reserved, they are guaranteed Fan-out: 3 Fan-out: 2 Fan-out: 2

Trees vs. meshes Trees Mimic multicast Each peer selects a parent peer The content/stream can be divided and sent across several trees Meshes A peer obtains pieces from any available peer There is not a strict relationship: child-parent Instead peers can collaborate in sharing pieces February 3, 2009 24

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 protocol For trees: a structured protocol (DHT) to find a parent For meshes: an unstructured protocol to find other peers With P2P signaling The functionality is distributed No need of a central entity February 3, 2009 25

Part IV: A P2P Content Distribution Service for IMS (work in progress) February 3, 2009 26

Incentives for P2P IMS network capabilities Smart IMS devices as peers: residential gateways, set-top boxes Transport: quality of service, resource reservation Telco policies: using capacity that is physically available but not paid for by the user Advantages All advantages of IMS: AAA, mobility, QoS Performance improvement goals Reduce load on core network / service provider Keep most of the traffic in the access network The telco controls the network P2P in a managed environment -> optimizations Business model Service providers -> Telco -> Users February 3, 2009 27

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 Provider Intermediary between the Multimedia Content Service Provider and IMS + transport layer Makes the content distribution transparent for the MCS Hides the specifics of the media content to the IMS/transport February 3, 2009 28 The Content Distribution Service is intended as an adaptation layer between the multimedia content and the mechanism (P2P or otherwise) used for content distribution

The idea February 3, 2009 29 Multimedia Services Content Distribution Service AS AS AS AS IMS Transport Network UE UE UE UE UE UE

The idea: IPTV simple example IPTV client Needs the address, port of a host delivering the video We call this host the content serving host February 3, 2009 30 UE alice@atlanta.com IPTV client CDS client cds.atlanta.com INVITE cds@atlanta.com SDP: provider=iptv3, ch=5 connect(ch5) AS INVITE cds@atlanta.com SDP: provider=iptv3, ch=5 183 Session Progress SDP: peer IP, port, protocol, codec 183 Session Progress SDP: peer IP, port, protocol, codec 200 OK 200 OK return IP, port, … ACK cds@atlanta.com ACK cds@atlanta.com

The infrastructure Different topologies for P2P P2P between UEs (same/different access networks) P2P between Edge Servers/Distribution servers February 3, 2009 31 Content Distribution Service IMS AS AS AS AS Multimedia Services Edge/Distribution Servers P2P P2P P2P P2P User Equipment (IMS terminals)

Business model February 3, 2009 32 Third Party Service Providers Trust Relationship Pays for the services retaining a % IMS CDS Provider Service Packager Transport Provider P2P streaming enabled network User-Network Interface Pay for data transport and third-party services Set-top boxes Users Telco

Case Study: IPTV Content: TV channels Number of pieces of content: relatively low (hundreds) Requirements Access time very important (channel switching) Low delay of live content (limited caching) Constant streaming (no interruptions) Design criteria P2P signaling not an option: latency too large Fast 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 33

Case Study: Video-on-Demand Content: published clips / user generated content Number of pieces of content: high (very high) Requirements Initial access time not critical Distributed content: caching/storage part of design Constant streaming after video started Design criteria P2P signaling could be essential (a lot of content to index) Redundancy P2P protocol can be optimized (no tit-for-tat) February 3, 2009 34

…other applications Other endeavors … telcos might pursuit Distributed computing Distributed storage Delay tolerant transfers Content distribution with social networking February 3, 2009 35

Conclusions February 3, 2009 36

Conclusions P2P content distribution in IMS = P2P in a managed network Does it make sense? Bulk of the Internet traffic: P2P and video Telcos don’t make money from selling bandwidth IMS/NG is the right platform for telcos P2P in the transport layer could be a cost-effective approach TISPAN began working in this direction (first draft Nov ‘08) But Although 3GPP is pushing IMS standardization… … deployment in near future is uncertain February 3, 2009 37

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