The Internet Real-Time
Laboratory
Henning Schulzrinne
CS Seminar
September 10, 2001
Laboratory overview
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12 PhDs
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4 at IBM, Juniper, Lucent, Telcordia
5 MS
5 visitors (Ericsson, Fujitsu, Mitsubishi,
Nokia, U. Coimbra)
China, Finland, Greece, India, Japan,
Portugal, Spain, Sweden, US, Taiwan
IRT topics
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Internet multimedia protocols and
systems
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Internet telephony and radio (J. Lennox, X.
Wu, K. Singh, K. Arabshian, W. Jiang, J.
Rosenberg, A. Dutta)
Content distribution networks (L. Amini, Y.
Nomura)
Internet event distribution (P. Koskelainen)
Wireless ad-hoc networks (M.
Papadopouli, S. Sidiroglou)
IRT topics
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Service discovery (W. Zhao)
Quality of service
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Pricing for adaptive services (X. Wang)
Scalable resource reservation protocols (P.
Pan)
Fair multicast resource allocation (P.
Mendes)
Internet multimedia
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Internet telephony = replacing the
existing circuit-switched system with
Internet-based systems
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Signaling = setting up calls
Quality of service
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Subjective evaluation of speech codecs, when
subjected to packet loss
Forward error correction at packet level
CINEMA
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Web interface
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Administration
User configuration
Unified Messaging
 Notify by email
 rtsp or http
Portal Mode
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3rd party IpTelSP
CINEMA architecture
Quicktime
SNMP
RTSP media
server
SIP/RTSP
Unified
messaging
SIP
conference
server
Telephone
switch
T1/E1
SIP proxy,
redirect
server
Web
server
SQL
database
RTP/SIP
NetMeeting
H.323
Software SIP
user agent
SIPH.323
convertor
PSTN interworking
PSTN
External T1/CAS
1 Call 9397134
Nortel PBX
Internal T1/CAS
(Ext:7130-7139)
2
Gateway
Call 7134
Ethernet
5551212
Regular phone
(internal)
5
3
SIP server
sipc
Bob’s phone
SQL
database
sipd
4
7134 => bob
Languages for service creation
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Traditionally, telecom services created
by switch vendors
Web model: allow users and
organizations to create custom services
Two models: sip-cgi and CPL
Sip-cgi: cgi scripts for call handling logic
Call Processing Language
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XML-based language
<incoming>
<address-switch field="origin" subfield="host">
<address subdomain-of="example.com">
<location url="sip:jones@example.com">
<proxy>
<busy> <sub ref="voicemail" /> </busy>
<noanswer> <sub ref="voicemail" /> </noanswer>
<failure> <sub ref="voicemail" /> </failure>
</proxy>
</location>
</address>
<otherwise>
<sub ref="voicemail" />
</otherwise>
</address-switch>
</incoming>
Mobile ad-hoc networks: 7DS
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Wireless infrastructure slow to emerge
(Metricom , 3G $$$)
802.11b cheap and simple to deploy
Mobile devices spread data in densely
populated areas (e.g., NYC)
7DS
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Content-independent: works for any
web object
Uses standard caching mechanism
After 25’, 90% of interested users have
2
data (25 hosts/km )
Also, data upload:
7DS research issues
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Effects of power conservation, collaboration
mechanism, wireless coverage range, density
of devices on information dissemination
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e.g., how fast does information
spread in such setting ? what is the
average delay that a host experience
until it gets the data ?
Performance analysis via simulations and
diffusion controlled processes theory
Mobility for Internet radio
p1
S1
S2
p2
M-Proxy
Backbone
S1
m1
S0
Local
Server
m1
m2
Local
Server
RTSP
Local
Program
Ad server
RTSP
Local
Program
Ad server
(a1,a2)
(a3)
BS1
BS0
(P1,a1)
(P2,a2)
m2
BS2
P2,a3
P2,a2
Fairness for multicast
Differentiated Service (DiffServ) networks divide
traffic into different service quality levels,
considering their quality requirements:
 Intolerant (loss&delay) applications will use
DiffServ Premium services, while tolerant
applications can use Assured services;
 Multimedia flows multicast to heterogeneous
receivers will use Assured services;
 Problem: Resources aren’t fairly distributed
between flows inside a DiffServ service.
Multi-receiver fair allocation
Provide fair distribution of Assured services
resources between multimedia multicast flows
considering:
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The number of receivers in each multicast flow;
A maximal utilization of resources;
Differential dropping between flows that overpass
their share of service resources;
A Multi-Receiver Utilization Maximal fair mechanism
(MRUM) is being developed.
Quality of service: pricing
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Bandwidth: decrease of marginal
returns adaptive services
U1
U2
U3
Cost
Budget
Bandwidth
Bandwidth pricing
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Congestion pricing
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See GWB, turnpike, electricity
Higher overall utility
Prices constant for periods O(min)
Auction or tatonnement pricing
Charge for usage and reservation