Transcript Internet Telephony - Trinity College Dublin

Internet Telephony
Dr. Donal O’Mahony
Networks & Telecommunications Research Group
Trinity College Dublin
© 1998 D. O’Mahony
1
Agenda
• Background to Internet Telephony
• Conventional Telephony
– Network Structure, Key technologies, Delay, Echo
• Internet Telephony Technology
– 1st Generation Protocols, Compression Techniques
• Product Review
© 1998 D. O’Mahony
2
Agenda…..
• 2nd Generation Systems
– H.320 Standards
– Product Review
• Directory Systems
– IRC..LDAP
• Integration with the PSTN
– Gateways, Next Generation Telcos
• Standards Organizations
– VoIP Consortium, ETSI TIPHON
© 1998 D. O’Mahony
3
Agenda...
• Case Studies
• Future Directions
• Implications for…
–
–
–
–
–
–
Large Corporations
Small Companies
Software Developers
Computer Network Managers
Network Operators
Telephony Equipment Vendors
© 1998 D. O’Mahony
4
Origins of Internet Telephony
• Xerox PARC started the EtherPhone project
between 1987-89
– used Ethernet as transport - concerned with Integration
and advanced telephony
© 1998 D. O’Mahony
5
VAT
• Lawrence Berkeley
Laboratories
developed the Video
Audio Tool (VAT) in
late 1992
– Work carried out by
M-BONE team
– Mainly interested in
Conferencing/Collab
oration
• CU-SeeMe from
Cornell in early ‘94
© 1998 D. O’Mahony
6
Major Technology Changes
• Phenomenal Internet Growth
– 1992: > 1 million hosts, ‘93: 2 million, ‘94: 3 million,
‘95: 5 mn, ‘96: 13 mn, ‘97: 19 mn, ‘98 30 mn
• SUN Audio …. PC Audio Cards become
commodity items
• Processors becoming more powerful - Intel 386
can easily handle uncompressed audio
• Availability of cheap modems at 28 and 32 Kbps
• Massive Competition in Global Telephony
Services - Callback etc.
© 1998 D. O’Mahony
7
Dawn of Internet Telephony
• Vocaltec - an Israeli startup company launched
their Internet Phone in February ‘95
• By 1997, this had grown to more than 35
competing Phone products - Optimistic Forecasts
Minutes per Day
(Million)
Source: Frost & Sullivan
700
600
500
400
300
200
100
0
IP telephony
world traffic
30% Capacity
10% Capacity
'96
'97
'98
'99
'00
'01
© 1998 D. O’Mahony
8
Users Perceptions of Internet Telephony
[Source Forester Research]
• 69% of Fortune 1000users plan to use Internet
Telephony by 2000 or later
• Barriers to entry
–
–
–
–
Need proof of cost savings (48%)
Quality and Reliability(42%)
Awaiting endorsement by major players(25%)
Technology needs to mature(17%)
• Spending (and Saving) on Internet Telephony tolls
will grow: (in billions)
– 1998:$0.03, 2000:$0.4, 2002:$1.03, 2004:$1.97
© 1998 D. O’Mahony
9
Conventional Telephony
• Very large industry e.g. Telecommunications
Service Revenue in 1994 was $195 billion, UK
was $25 billion
• Historically made up of Monopoly Carriers
operating in an uncompetitive environment
© 1998 D. O’Mahony
1
0
Network Structure
Analog
Telephone
Telco
Digital
Switch
Digital
Trunk
Telco
Digital
Switch
Local Loop
ISDN Digital
Phone
International
Gateway
© 1998 D. O’Mahony
1
1
Digitizing Voice
• Telephone Network is engineered to carry a
frequency range of 300 Hz to 3.4 KHz
• Achieved using 8,000 samples per second, 8 bits
per sample
– Yields standard 64Kbps Pulse Code Modulated (PCM)
data stream
© 1998 D. O’Mahony
1
2
Digital Trunk Circuits
• In Europe
–
–
–
–
16
S
E1 - 32 x64Kbps = 2Mbps
E2 - 4 x E1 + framing approx 8Mbps
E3 - 4 x E2 + framing approx 34Mbps
E4 - 4 x E3 + framing approx 140 Mbps
32
• Signaling Information is carried using a protocol
called Common Channel Signaling System #7 or
SS#7
© 1998 D. O’Mahony
1
3
Call Setup for a Typical Phone Call
Originating
Exchange
Intermediate
Exchange
Initial Address Message
Initial Address Message
Address Complete
Address Complete
Ring Tone
Answer
Answer
Conversation
X
Clear Forward
Release Guard
X
Clear Forward
Release Guard
X
Speech Path established
X
Speech Path Cleared
© 1998 D. O’Mahony
1
4
Voice Path
2-wire
Analog
2 independent
digital streams
PCM
Codec
2-wire
Analog
PCM
Codec
Hybrid
• Voice incurs some delay at each stage
– e.g. 0.3ms for PCM coding, 5s per km of optical fibre
– Imperfections in Hybrid cause some echo
– combination of delay and echo can cause problems
• CCITT G.114 recommend
– one-way delays of 0-150ms are acceptable
– 150ms-400ms acceptable provided echo
1998 D. O’Mahony
control/suppression is used >400ms is ©unacceptable
1
5
Conventional Telephony Summary
• Provides a global network with very high
connectivity
• Network Characteristics
–
–
–
–
circuit switched
constant bit-rate - 64Kbps
High Quality - 64Kps
Guaranteed Max Delay (<400msec)
• Service
– Expensive
– Lo-Tech [ IN-Services?]
– Not Integrated
© 1998 D. O’Mahony
1
6
Competition
• Traditional Monopolies are facing competition in
all areas
– Local Loop
• Regulators insisting on free access to multiple operators
• New Technologies: Wireless Local Loop, Cable Telephones,
Electric Power Lines
– National Network
• New infrastructure providers: Railway Companies, Electric
Power Companies, Private Microwave Networks
– International Networks
• Emergence of Mega-Carriers and Alliances
– Call-Back….
© 1998 D. O’Mahony
1
7
Telephone Tariffs
• National tariffs are set by PNO (often monopoly)
• International tariffs agreed on a bilateral basis
– Accounting rate” mechanism invented in 1865 for
telegraph traffic
– Countries A and B agree that it costs $X dollars/min to
terminate a call - any imbalance in the call-minutes
between them leads to settlement payment of $X/2 per
minute of the imbalance
• Calls can’t get cheaper than the settlement rate
• Inefficient (expensive) carriers are rewarded - U.S. paid out
>$5billion in 1994
• Large Call-Back market has developed
– Internet Telephony circumvents the accounting rate
© 1998 D. O’Mahony
1
8
Call-Back
• Accounted for Estimated 600 million minutes
traffic in 1995 ~equiv 1% Total Telephone Traffic
or 4% of outgoing U.S. Traffic
• Assuming a call-back average rate of US$0.45 =>
Call-back was US$270 million business in 1995
and growing
© 1998 D. O’Mahony
1
9
Internet Telephony
– Internet Network Structure
IP Datagram
IP
IP Datagram
Router
Router
IP
IP
IP
– IP Datagram - a variable sized packet is delivered in
store-and-forward fashion across a network of routers
– Service is un-reliable, variable delays, variable bit rate,
designed for data
© 1998 D. O’Mahony
– Fixed Cost- usually cheap
2
0
Using the Internet to carry Voice
The 1st Generation
• Capture sound using SoundBlaster Card
• Code using 64Kbps - or other codec
• Pack into simple frames
Sequence
Number
Flags Audio Timestamp
Format
Speech Samples
• Send using User Datagram Protocol to fixed or
pre-arranged port at pre-arranged address
• Timestamp used to detect lost frames - substitute
comfort noise
© 1998 D. O’Mahony
2
1
Voice Coder/Decoder (CODEC)
• Simple PCM Speech @ 64Kbps is covered by
G.711 - finalized in 1972
• G.721 - ADPCM @ 32Kbps in 1988
• ETSI GSM - Regular-Pulse Excitation - Linear
Predictive Coding (RPE-LPC) @ 13Kbps - in
1987
• Seat of the pants…. Throw away every second
sample
• More advanced algorithms were developed in later
years
© 1998 D. O’Mahony
2
2
Delay
• Sound captured in sound card - Delay dependent
on buffer size
• Codec Delay e.g. RPE-LPC has 20ms delay
• TCP/IP stack - packet assembly delay
• V.34 modem introduces 35ms delay
• Delay in Internet Transit ?????? - unpredictable,
depends on network load, destination e.g. 10ms to
500ms and more
• Jan’98 - UUNet ExtraLink VPN guarantees
<150msec delay, Sprint’s VPN is <140msec
© 1998 D. O’Mahony
2
3
Making the Connection
Address Server
Caller
Callee
IP Address/Port
• The Internet allows packets to be sent to a specific
IP address/port
• Phone software must be running and caller must
know IP/port before a call can be setup
• Particularly difficult if IP address is dynamically
assigned - dialup internet access is a problem
• Need some kind of address server
© 1998 D. O’Mahony
2
4
1st Generation Internet Phones
• Vocaltec IPPhone
– announced February 1995
– Offered a range of Codecs
• Vocaltec VSC 8Khz
• The DSP Group’s TrueSpeech
8Kbps
• GSM
– Used Internet Relay Chat
(IRC) Server Network to find
callees IP address
• Cost: Initially $100 down to $50
© 1998 D. O’Mahony
2
5
1st Generation Internet Phones
• WebPhone from Netspeak Corporation (aka
Internet Telephony Company)
• Launched ver 1.0 in August ‘95
• Had many additional features
– voice mail, four line display, caller ID, Do not
disturb, Speed Dial, Call Hold/Mute,
Conversation Encryption
– Uses Enhanced GSM
(12Kbps) or TrueSpeech(8.5Kbps)
• Address Server can
only be searched - not
browsed
© 1998 D. O’Mahony
2
6
1st Generation Internet Phones
• Netscape Cooltalk
– Released with
Netscape 3.0 in
March 1996
– Cross-Platform availability : W3.1,W95,WNT,Power
Mac, Solaris, HPUX, Iris, DEC UNIX
– Uses GSM and Voxware RT-24 (2.4Kbps)
– Incorporates Echo Cancellation and Silence Surpression
Controls
– Also includes a chat tool and shared whiteboard
– Used IS411 Server to establish contact with other users
© 1998 D. O’Mahony
2
7
1st Generation Internet Phones
SpeakFreely
• First public release in
August ‘95 - developed by
John Walker (founder of
AutoDesk)
• Large variety of protocols : SF, RTP, VAT
• Large variety of codecs: PCM, GSM, LPC, LPC10
• Security features - can use PGP for key agreement
• Look-Whos-Listening Server for contact
© 1998 D. O’Mahony
2
8
1st to 2nd Generation
• First generation systems all took different
approaches to
–
–
–
–
connection setup, negotiation
protocol encapsulation
add-ons e.g. white-board, chat tools
No interworking was possible
© 1998 D. O’Mahony
2
9
H.320 Series Recommendations
• Originally developed to allow for VideoTelephony and Video-Conferencing applications
across ISDN Networks
• H.320 was a framework for many other standards
Rec. H.320
Rec. H.261/2/3
Video I/O equipment
Rec. H.221
I.400-Series Rec s.
Video codec
H.200/AV.250-Series Recs .
Network
Audio I/O equipment
Audio c odec
Delay
T-Series, H.200/AV.270-Series Recs., etc.
Telematic equipment
Recs. H.242, H.230, H.221
MUX/DMUX
Network
interface
MCU
End-to-end signalling C&I
System control
End-to-network signalling
I.400-Series Recs.
T15 02 49 0-90 /d 01
© 1998 D. O’Mahony
MCU
Multipoint control unit
3
0
H.320 in Data Networks
• H.321 adapted the H.320 series to run on B-ISDN
(ATM) network
• H.323 (May’96) did the same for networks with a
non-guaranteed quality of service e.g.
Scope of Recommendation H.323
Video I/O equipment
– Ethernet, Token
Ring, FDDI or
Audio I/O equipment
– IP
– Should be possible to
Applications
inter-work with H.320 User Data
T.120, etc.
terminals in ISDN
or B-ISDN
System Control
environments
User Interface
Video Codec
H.261, H.263
Receive
Path
Delay
Audio Codec
G.711, G.722,
G.723, G.728,
G.729
H.225.0
Layer
Local Area
Network
Interface
System Control
H.245 Control
Call Control
H.225.0
RAS Control
H.225.0
© 1998 D. O’Mahony
3
1
Call Signaling in H.223
• A number of distinct phases are defined
– Phase A - Call Setup - Can
employ the services of a
Gatekeeper
– Phase B - Capability
exchange
– Phase C - Establishment
of Audio-Visual Comms
– Phase D - Call Services e.g.
conference expansion
– Phase E - Call Termination
Endpoint 1
Gatekeeper 2
Gatekeeper 1
Endpoint 2
ARQ(1)
ACF/ARJ(2)
Setup(3)
Call proceeding(4)
ARQ(5)
ACF/ARJ(6)
Alerting(7)
Connect(8)
RAS Messages
Call Signalling Messages
© 1998 D. O’Mahony
3
2
H.323 Protocol Stacks
AV Appl.
G.7XX
Audio
H.26X
Video
Real-Time
Protocol
(RTP)
Q.931 Terminal Control and Mgmt
RAS
Term.
RTCP
<->
GW
Unreliable Transport (UDP)
H.225.0
Call
Signal
H.245
Call
Signal
Reliable Transport (TCP)
Data Appl. or
T.126/T.127
T.125
MCS
T.124
GCC
T.123
(ISO+TCP)
Network Layer (IP)
Link Layer
Physical Layer
© 1998 D. O’Mahony
3
3
Channels
• A number of Logical Channels are setup for
different purposes
• Audio/Video are encapsulated in the Real Time
Protocol (RTP) - specs for H.261, G.7111 etc
• Control/Signaling Channels use TCP
• A Resource Reservation Protocol (RSVP) channel
is setup to allow resources to be reserved (if
supported) and for feedback on QoS to be
exchanged
• T.120 provides for data applications such as chat
& whiteboard
© 1998 D. O’Mahony
3
4
ITU Codecs
Coder
Bit Rate
(kbit/s)
Complexity
% 100 MHz
Pentium
G.723.1
5.3/6.3
35-40%
97.5ms
G.729
8
~50%
35ms
G.729A
8
25-30%
35ms
G.721
32
<1%
<1ms
G.728
16
~65%
3ms
End to End
Delay
Source: Lucent
• All codecs are available for licencing
© 1998 D. O’Mahony
3
5
2nd Generation Internet Phone
Microsoft Netmeeting
• Netmeeting 2.1 supports
H.323 for video/audio
• conferencing, application
• sharing,shared clipboard,
file transfer, whiteboard
• Many different codecs
supported for audio
• including G.723.1, Lernout
& Haspie (5-16Kbps)
• Uses ILS to locate users
© 1998 D. O’Mahony
3
6
2nd Generation Internet Phone
Intel IVPhone
© 1998 D. O’Mahony
3
7
2nd Generation Internet Phone
Netscape Conference 4.0
• Released as an integral component of Netscape
Communicator
– Supports H.323 audio
conference only, whiteboard,
chat, collaborative
web browsing and
file transfer
– Range of codecs: G.711,
telemedia SX 8300P, Voxware
RT-29/RT-24
– Uses a Dynamic Lookup
Server at four11.com to
locate called parties
© 1998 D. O’Mahony
3
8
2nd Generation Internet Phone
Vocaltec Internet Phone 5.0
• Supports H.323, with Video, but
not by default - chat, whiteboard
file transfer possible
• 5 codecs supported - Vocaltec VSC is
default - proprietary video codec too
• Uses Community Browser with
interest groups to find callee
• Good support for PC calling via
Delta3 and others
© 1998 D. O’Mahony
3
9
Future H.323 Changes
• ITU ratified H.323 Ver 2 in Jan/Feb‘98
• Major updates:
• Refinements for Internet [Telephony]
 Addressing, Directory, Scalability, QOS
• Encryption
• Large scale conferences
 Distance learning, Auditorium mode
• Richer media control
 layered video codecs, reopen of LCs, ‘big
pipes
 Feature creep
 more Facility signaling, redundancy,
FastStart
© 1998 D. O’Mahony
• IETF alignment
4
0
H.323v2 enhancements
• H.235
– Enhanced Security Allows users to authenticate
themselves using passwords, certificates or challengeresponse mechanisms
– Will allow Internet Telephony users to authenticate
themselves to Gateways and/or Gatekeepers
• Fast Call Setup
– possible to setup a call using a single Round Trip
© 1998 D. O’Mahony
4
1
Vocaltec Gatekeeper
• Announced Feb’98 - availability Q2’98 - runs on
NT Server 4.0
• Targeted at ‘carrier-grade’ IP Telephony for
service provider and corporate markets
• Provides centralized addressing for IP terminals
• Can provide least cost routing (e.g. via PSTN G/W
or Internet)
• Performs Authorization & Billing using H.235
security
• SNMP Manageable or using Vocaltec Network
Manager
© 1998 D. O’Mahony
4
2
Directory Services
• Need a Phonebook equivalent
• Present systems often list all available users
• Some attempt to categorize into communities (e.g.
General, Music, with camera etc)
• Invites calls from strangers!
• Novelty factor will decline
© 1998 D. O’Mahony
4
3
Internet Relay Chat (IRC)
• Already existing network of servers to allow textbased chat rooms
• Initially Vocaltec used the Join and list primitives
of IRC as a rendezvous mechanism
• Dedicated Network of Internet Phone servers grew
up
• Latest release uses a Community Browser - which
uses a development of this mechanism
© 1998 D. O’Mahony
4
4
Bigfoot,Switchboard, Infospace, Four11
• Internet Telephony can use any mapping of Email->IP Address
• Many on-line directory services that register users
can store this information on request
• Access via general purpose or specialized WWW
browsing software
© 1998 D. O’Mahony
4
5
User Location Service
• ULS is a Dynamic Registration Protocol designed
by R. Williams in 1996 - now an expired internet
draft
• Four11 (www.four11.com) operates a directory
service based on a User Location Service (ULS)
protocol
– supports Connectix VideoPhone ,CU-SeeMe ,Netscape
CoolTalk ,VDOnet's VDOPhone ,Netspeak WebPhone
Microsoft NetMeeting
– Identifies user who has come on-line, with internet
address and phone application
© 1998 D. O’Mahony
4
6
LDAP
• A Lightweight version of the X.500 Global
Directory Access Protocol- now at 2.0
Read, search,
modify
X.500 Directory
Hierarchy of Objects
• Designed for static information - no facility for
refresh and expire operations
• LDAP 3.0 will support this
© 1998 D. O’Mahony
4
7
LDAP 3.0
• Many facets to the 3.0 extensions - but dynamic
entries are of principal interest to Internet
Telephony
• - Internet Draft at Dec’97 ftp://ietf.org/internet-drafts/draft-ietf-asidldapv3-dynamic-07.txt - now submitted as a proposed standard
Refresh(NewTTL)
dynamicObject Class
EntryTTL attribute (secs)
© 1998 D. O’Mahony
4
8
Microsoft Internet Locator Service
• Based on LDAP 2.0 with proprietary extensions
• Defines a User Object and a Meetingplace Object
Registration,Unreg,
Refresh, Resolve
Query, Modify
user
Country
CName
Meeting Place
Description
Atendee
• No Compatible Servers : Example ls5.microsoft.com
• Will migrate to LDAP 3.0 in the future
© 1998 D. O’Mahony
4
9
PSTN Integration
• Started with the ‘Free World Dialup’ experiment
in October’95
• Since local calls are free in many areas, the
fledgling Internet Telephony community tried to
establish primitive break-out’s into the PSTN
I/Tel
Software
Internet
Modified
Modem
• Established gateways in Jakarta, Tokyo 7 New
© 1998 D. O’Mahony
York - FWDII is underway
5
0
Internet Telephony Gateways
• Generally consist of one or more PSTN lines and
DSP support for Voice compression algorithms
• Example Dialogic Single-Line system approx
$1,000
© 1998 D. O’Mahony
5
1
Bulk Gateways
• Lucent technologies have developed ‘Internet
Telephony Server-SP (Service Provider) to allow
Phone-to-Phone calling across an internet link for
many lines
• Netspeak Webphone Gateway Exchange (WGX)
has up to 4 E1 or T1 interfaces (96 lines)
– can interface to ACD hardware for VoIP Call Centre
applications
– working with Telestra on SS7 support for gateway
© 1998 D. O’Mahony
5
2
Internet Telephony eXchange Carrier
(ITXC)
• Subsidiary of AT&T - headed by Tom Evslin)
former VP who ran AT&T Worldnet -started
July’97- Vocaltec has minority stake
• provides wholesale switching, transport, billing
and settlement functions to ITSPs (Internet
Telephony Service Providers) for IP telephony
(Internet telephony).
ITSP Gateway ITXC
Intranet
Public
Network
© 1998 D. O’Mahony
5
3
Next Generation Telcos
Delta Three
Operates an Internet Telephony Backbone providing
PC-to-Phone calling - use Vocaltec’s Internet Phone or (free)
Delta3 Internet Phone Lite
Phone-to-Phone Calling (using calling card+pin)
Gateways around the world: London, HongKong, Paraguay,
France etc
Economics
Codec Delta Three uses is 11 kbs
TCP/IP overhead adds 5 kbs
Kilobit range comes down by 40% with silence suppression
End result: typically under 10 kbs
Over 200 simultaneous calls over a data E1
PC-to-Phone Tariffs e.g. Feb’98: US: 12¢/min, UK 16¢, Tokyo
19.5¢
© 1998 D. O’Mahony
5
4
Other Next Generation Telcos
• US Global Link to offer Phone-to-Phone Internet
Telephony
– Plans to install 1000 internet telephony switces (175 by
Jan’98)
– rates of 20-40% lower than callback
• IDT and Net2Phone offering PC-to-Phone calls
via their U.S. gateway
• VIP Calling offers Internet
Telephony for carriers via
their global network of
pops
© 1998 D. O’Mahony
5
5
Standards Organizations
The Internet Telephony Interoperability
Consortium
• Home page @ http://itel.mit.edu
• A research organization focused on
– interoperability, pricing, regulatory issues and business
effects
– act as a feeder body to standards orgs such as IETF
© 1998 D. O’Mahony
5
6
The Internet Telephony Consortium
• 3 principal areas
– Architecture for Interoperability
• control arch, call mgt and edge signalling, ULS/Mobility,
Policy routing, standards
– Efficient Resource Allocation
• network resource characterization, Economic Models,
Performance models, Yield Mgt, user Feedback
– Industry Structures, Business Strategies and Policy
• Business Model Framework, Business Strategies, Evolution
and Convergence, Regulation and Policy Analysis, Strategies
© 1998 D. O’Mahony
5
7
The Internet Telephony Consortium
Planned Deliverables
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Applications Testbed: Construction of Experimental Setup and Conduct of Experiments
Architectural Implications of Internet Pricing Models
European Internet Regulatory Strategies
Internet Telephony Business Models
Internet Telephony Cost Model
(Proposed - Internet Telephony Network Testbed)
Internet Telephony Regulation and Policy Analyses
Internet Telephony Strategies
Interoperability of Directory Services
Interoperability Requirements for Personal Mobile Multimedia Services
Intranet Telephony Cost Model
Meta-Net Architecture
Roadmap of Standards for Internet Telephony Interoperability
Taxonomy of Internet Telephony's Industrial Structure
User Feedback Studies
Yield Management
© 1998 D. O’Mahony
5
8
Standards Organizations
The Voice over IP Forum
• Interest Group of the IMTC (International
Multimedia TeleconferencingConsortium ) formed in May’96
– representatives mainly of multimedia software
developers - focussed on interoperability
– coordinate with H.323 interop group at IMTC
• March’97 - select G.723.1(6Kbps) as default
codec
• Sponsor regular H.323 interoperability tests
© 1998 D. O’Mahony
5
9
Standards Organizations
ETSI
• Initial workshop help at Sophia Antipolis in March
‘97
• 1st formal meeting of the Telecommunications and
Internet Protocol Harmonization over Networks
(TIPHON) in late May’97
• Focus is on Interworking between existing
networks: PSTN, ISDN, GSM and VoIP
© 1998 D. O’Mahony
6
0
TIPHON Project Status
• 3 Phases
–
–
–
–
–
Phase 1 - VoIP TO PSTN/ISDN/GSM - by end of ‘97
Phase 2 - PSTN/ISDN/GSM TO VoIP - by end of June’98
Phase 3 - PSTN.. To PSTN… via VoIP - by end of Sept’98
Phase 4 - VoIP to VoIP via PSTN - by end Sept’98
Project completion by end of ‘98
• 6 Working Groups:
–
–
–
–
–
–
•
WG 1 - Requirements for service interoperability
WG 2 - Architecture and reference configurations
WG 3 - Call control procedures
WG 4 - Naming, Numbering and Addressing
WG 5 - End-to-End Quality of Service aspects
WG 6 - Verification and Demonstration Implementation
Feb’98
– Stable drafts for Phase 1 - table of contents for Phase 2
© 1998 D. O’Mahony
6
1
Demonstration Network - TIPHONET
– should demonstrate connectivity between nodes at
• ETSI (SophiaAntipolis), France Telecom (Caen)
• Post & Telecom Austria (Vienna and Graz) - Operational by mid-Nov’97
© 1998 D. O’Mahony
6
2
Internet Engineering Task Force (IETF)
Multiparty, Multimedia Session Control (MMUSIC)
• MMUSIC has drafted protocols for:
– distributing session descriptions -- Session Description Protocol (SDP) and Session
Announcement Protocol (SAP)
– providing security for session announcements -- SAP Security
– controlling on-demand delivery of real-time data -- Real-Time Stream Protocol
(RTSP)
– initiating sessions and inviting users -- Session Initiation Protocol (SIP)
– managing tightly-controlled sessions -- Simple Conference Control Protocol
(SCCP)
•
SIP seen as an alternative for Internet Telephony
–
–
–
–
–
•
addresses directory services
much more light-weight and flexible than H.323
Can gateway to Q.931, H.320
main advocate: Henning Schulzrinne
http://www.cs.columbia.edu/~hgs/sip/
Also the PSTN IP Integration Group (PINT) addressing how IP apps can
enrich and request PSTN services e.g. WWW yellow pds with
dialling
© 1998
D. O’Mahony
6
3
ACTA Petition
• On March 4th, 1996, the American Carriers
Telecommunications Association petitioned the
FCC to the effect:
– Vocaltec, other s/w companies and ITSP are providing
telephony services, and should be regulated
– Not in the public interest to give away telephony
services
– FCC should stop ITSPs until new rules can be made
– FCC has authority to regulate internet and ITSPs (as
interstate carriers)
© 1998 D. O’Mahony
6
4
VON Coalition
http://www.von.org
• On March 18th, the VON Coalition was formed to
oppose ACTA petition
– Over 400 individual and 80 corporate members
– counter argument based on the fact that Internet
Telephony is an emerging technology
– No way to draw the line between IT and any networked
multimedia application
– IT can be used to link schools, libraries at low cost!
© 1998 D. O’Mahony
6
5
Regulation
• Former FCC Chairman Reed Hundt in July ‘96 •
We shouldn't try to impose old rules on new ideas.I'm against subjecting
Internet telephony to the old rules that apply to conventional circuit-switched
voice carriers, even while we're trying to change those rules.
• On Sept 8th ‘97: Statement by Larry Irving,
National TeleC & Info Admin at VON Conference
“President Clinton…spoken about need to let new
telecom technologies blossom”
• New worries in February ‘98
© 1998 D. O’Mahony
6
6
European Position
• Voice regulation is governed by EU Directive
90/388/EC
• On on 10th Jan’98, Commission issued a notice
(http://europa.eu.int/en/comm/dg04/lawliber/en/voice.htm) on Internet Telephony
– following a period of public consultation
• Main Points
– Technology will eventually cause a convergence of Internet
and conventional Telephony
– Today’s Internet Telephony cannot yet be characterized as a
Public Telephone Service
– No Universal Service Obligations
• Review in future at least by Jan 2000
© 1998 D. O’Mahony
6
7
Internet Telephony Applications
2nd Line for Internet Users
• Telestra and Netspeak have developed SS#7
gateway to allow calls to active internet users
PSTN
Gateway
Internet
• Ericsson “Phone Doubler” - demonstrated in
March’97 achieves similar results
© 1998 D. O’Mahony
6
8
Internet Telephony Applications
Telecom Finland’s NeoPhone Service
• Integrated Voice/Data in one terminal
• Not an internet phone - voice carried across IP on
corporate networks and across PSTN or between
corporate networks using Telecom Finland’s ATM
networks
• Integrated with TF’s Intelligent Network and
VIPGate nation-wide company number service
(VPN)
© 1998 D. O’Mahony
6
9
Internet Telephony Applications
Etherphone LAN PBX
• Phonet ( Israeli startup) produce EtherPhone
which provides PBX functions over a LAN
LAN
PSTN
EtherPhone
Server
• Etherphone servers can do limited ACD
• Can link Etherphones across WAN links
© 1998 D. O’Mahony
7
0
Internet Telephony Applications
VocalTec’s Surf&Call
• Plug-in for Netscape 3.0 or Internet Explorer 3.0
• Allows “CALL” buttons to be put on WWW
pages
• Pressing initiates an Internet Telephony Call to
call centre
© 1998 D. O’Mahony
7
1
Future Developments
• Convergence on Codec’s (G.723.1 [6.3Kbps] or
G.720 Annexe A [8Kbps])
– Efficient implementations
• Low Delay TCP/IP stacks
• Increased support for RTP
• Incorporation of Java Media Framework API
• Adoption of LDAP 3.0 - shakeout in directory
services area
© 1998 D. O’Mahony
7
2
Future Developments...
• Increased support for H.323 additional function
e.g. call transfer, call waiting, ACD features
• Convergence of PBX and IP Telephony Server
More support for H.320 multipoint operation
• Each availability of MCUs
• Much more users
© 1998 D. O’Mahony
7
3
Implications of Internet Telephony
for Large & Small Companies
• Opportunity to integrate voice/data
• PBX replacement
• New opportunities to route calls to achieve cost
savings - over corporate intranet, via next gen
telcos
• Better service to customers using Call Centres
coupled with Internet Telephony
© 1998 D. O’Mahony
7
4
Implications of Internet Telephony
for Software Developers
• Represents a paradigm shift in telephony
• Opportunites to provide components of the overall
solution
• Gateways, Management, accounting, end-to-end
security, routing, firewalls etc.
• New lease of life for ISDN-based (H.320) systems
© 1998 D. O’Mahony
7
5
Implications of Internet Telephony
for Computer Network Managers
• Play increasing role in Telephony service
provision
• Challenge of ensuring Network QoS
• Increased reliability constraints
• Need Multi-media and networking competence in
Support function
© 1998 D. O’Mahony
7
6
Implications of Internet Telephony
for PTOs
• As Internet Telephony grows : - gain in local call
revenues, leased lines, loss in International Calls
• Many US telco’s have no local call charges =>loss
• Tarifica’s NetEffect Study
306
KDD
350
AT&T
161
Telecom Italia
France Telecom
94
173
Deutsche Telekom
105
British Telecom
0
50
100
150
200
250
300
Revenue Loss in International Calls Market in the Year
2001 (US$ millions)
350
© 1998 D. O’Mahony
7
7
Impact on PTOs..
•
•
•
•
Some new opportunities
Extra Leased line revenue
Opportunities for backbone service provision
Adopt two-tier pricing : circuit-switched and
packet-switched
– maintain price-sensitive customers
– lower network cost
– bypass accounting rate system
• Jan’98 Conference: How an ISP can become a
TELCO!
© 1998 D. O’Mahony
7
8
Implications of Internet Telephony
for Telephony Equipment Vendors
• Paradigm Shift
• Telephony no longer a separate market
• Increasing competition from Computer
community
• PBX will become a network server/gateway
• Decreased demand for concentional phone
• Emergence of PCs disguised as phones!
© 1998 D. O’Mahony
7
9
Conclusions
• A time of great change
– from Ham-Radio to fledgling industry in 2-3 years
• Will affect many different industries
• Creates many different threats and opportunities
• Clear that Internet Telephony is here to stay
© 1998 D. O’Mahony
8
0