4 iptv koert vlaeminck - biblio.ugent.be · iptv deployment: trigger for advanced network services!...
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IPTV Deployment:Trigger for advanced network services!
T. Wauters, K. Vlaeminck, W. Van de Meerssche,S. Van den Berghe, F. De Turck, B. Dhoedt,
P. Demeester, E. Six, T. Van Caenegem
Overview
•Introduction–advanced access network services–IPTV
•Access network architecture–network transformation–network processing power
•Time-shifted television–concept–caching algorithms–RTSP proxy
•Conclusions
Overview
•Introduction–advanced access network services–IPTV
•Access network architecture–network transformation–network processing power
•Time-shifted television–concept–caching algorithms–RTSP proxy
•Conclusions
Introduction
•Service network requirements–content delivery (IPTV, VoD)•high bandwidth, low jitter
–multiplayer games (server based, P2P)•low delay
–distributed storage•low delay, high availability
–conferencing (IP telephony, video conferencing)•low delay and jitter
–home management (automation, security)•high availability
Introduction
•High priority: IPTV services–today: broadcast TV (live) or VoD (older content)•highly loaded VoD servers at the network edge•complete files are stored
–solution: time-shifted TV for (very) recent content•distributed servers in the access network, storing fragments
Broadcast TV
broadcastserver
Start of livebroadcast
t1h 1 day
Time-shiftedTV
access server
1 week
Video onDemand
regional server
Video onDemand
central server
# requests
Overview
•Introduction–advanced access network services–IPTV
•Access network architecture–network evolution–network processing power
•Time-shifted television–concept–caching algorithms–RTSP proxy
•Conclusions
Access network architecture: current
–Access Network per Service–Broadband Internet (DSL / ATM based)•PPP terminated in single device (BAS)•Single device per subscriber–NAT breaks E2E connectivity
•PPP setup hampers autoconfiguration•PPP conflicts with application-based QoS
and multicast support
PSTN
IP aware
IP aware
PPP
switch
CPN
IPtelephone
Service enablers(e.g. firewall,
caches)
Internet
ATM switch
aggregationnetwork
CPN
NAPedge router
BASDSLAM
telephone
telephone
ADSLmodem
gateway
ISP1Edge router
ISP2
IP DSLAM
IPawareness
Newservices
IP aware
IP aware
Access network architecture: evolution–Converged access network– IP awareness•Multicast support•Local P2P traffic
–Multi edge•Scalability•High availability
–New services (triple play)–Application based QoS
Access network architecture: evolution
Current ATM-basedbroadband aggregation
ATM DSLAMs
•Unintelligent Layer 1 aggregation•Low-speed ATM uplinks•Mostly Central Office - based
Complex, fixed connections
•PPP-based•Bound to DSL CPE in the home•Provisioning cost high
Centralized B-RAS
Lack of network resiliency
•Optimized for best-effort internet•Lack of scalable routing and QoS•Typical OC-12 handoff to IP core
•Outages tolerated•Minimal financial repercussions
Next-generation Ethernet/IP-based broadband aggregation
IP DSLAMs
•Intelligent aggregation with multicast support•Gigabit Ethernet Uplinks•Increasingly RT-based
Simple, flexible connections•DHCP-based•Independent of device•User-based•Provisioning cost low
Distributed routers
Highly available network
•Optimized for QoS-sensitive services•Highly scalable•10 GbE handoff to IP/MPLS core
•Little to no tolerance of service interruptions•Risk of churn if reliability metrics aren’t met
•Increasing need for powerful and flexiblenetwork systems–today: fixed-function ASICs or low-performance
general purpose processors
Access network: processing power
•Long time to market•High cost•Inflexible: little reuse
•Low performance•Power requirements
Con
•Very fast•Highly scalable
•Programmability: flexible•Component reuse•Relatively low cost (RISC)
Pro
ASIC–based solutions(Custom silicon)
GPP–based solutions(General Purpose Processor)
–next generation: network processors (NPU)•A special-purpose, programmable hardware device that
combines the low cost and flexibility of a RISC processor withthe speed and scalability of custom silicon
Access network: processing power
Per
form
ance
/Wat
t
Flexibility
GeneralPurpose
Processor
CustomSilicon(ASIC)
NetworkProcessor
Overview
•Introduction–advanced access network services–IPTV
•Access network architecture–network transformation–network processing power
•Time-shifted television–concept–caching algorithms–RTSP proxy
•Conclusions
Time-shifted TV
User 1: real-time
User 2: delayed t1
User 3: delayed t2
2
3
1
core network
regional network
access network
CS: central serverER: edge routerAR: access routerAM: access multiplexer
CS ER
AR
AM
•Network view–caching of fragments–p2p caches
Time-shifted TV
•Streaming diagram
t_program
storage
t_storage
t_pause
t0 t1 tw t2 t_viewing
User 1 User 2 User 3
Time-shifted TV
•Caching algorithm–small part S for learning (< 1 GB)–large part L for storage of popular/distant fragments
programstored
locally?
request for program p
windowappropriate?
- stream fromother cache- adapt An,p
- stream locally-set to “occupied”- adapt An,p
- stream fromother cache
- stream fromserver- cache in S
is itnew?
no
no no yesyes
yes
Time-shifted TV
ER AR AM•Input parameters–5 tsTV channels–6 programs per channel–45 minutes per program
•Deployment options–hierarchical caching•caches at AR and AM level
–co-operative caching•co-operating caches at AM level
Time-shifted TV
0
20
40
60
80
100
0 1 2 3 4cache size [GB]
%re
qu
ests ER -> AR
AR -> AM
AM -> AR
0
20
40
60
80
100
0 1 2 3 4cache size [GB]
%re
qu
ests ER -> AR
AR -> AM
AM -> AR
•Hierarchical caching
AM caches only AR and AM caches
Server load reduced by 50% to 70% with 0.5GB caches
ER AR AM
Time-shifted TV
•Co-operative caching
AM caches only
Server load reduced by 95% with 6 co-operating 0.5GB caches
0
20
40
60
80
100
0 1 2 3 4cache size [GB]
%re
qu
ests
ER -> AR
AR -> AM
AM -> AR
ER AR AM
Time-shifted TV
•RTSP proxy–implementation using RTP / RTCP / RTSP
CacheVerdict
Manager
StreamTracker
RTSPProxy
Streamer
Packet Handler
ProgramGuide
CacherCacheState
Manager
CSE RTSP RTP EPG
Time-shifted TV
•RTSP proxy–measurements•AMD AthlonTM 64 (512MB RAM)•delay between PLAY request and first RTP packet in a
server - proxy - client configuration
0
5
10
15
20
25
30
35
40
content notcached at
proxy
contentcached at
proxy
server only(proxy
disabled)
del
ay[m
s]
m in delay
av delay
max delay
Overview
•Introduction–advanced access network services–IPTV
•Access network architecture–network transformation–network processing power
•Time-shifted television–concept–caching algorithms–RTSP proxy
•Conclusions
Conclusions
•Access network transformation–from ATM based broadband aggregation to multi-
service IP-aware access networks
•IPTV–identified as highest-priority, bandwidth intensive
residential telecom service–server load and access network load reduced
effectively through time-shifted TV using distributedproxy streamers