Transcript Internet Telephony

Internet Telephony;
-existing and emerging standards
EN/FAD 109 0015
Lill Kristiansen, Ericsson AS
Product Unit Internet
[email protected]
www.ericsson.com/ipservices
www.ericsson.com/gatekeeper
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Lill Kristiansen, Ericsson AS
Enablers for telephony over IP
• WEB explosion
– user friendly GUIs,
– IP as common denominator
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• A global data network with relatively cheap
bandwidth
• Powerful Multimedia PCs
• A need for advanced services
– ex: ‘true CTI’ integration of company’s web pages,
customer base, attendants, click-to-dial, email etc
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Lill Kristiansen, Ericsson AS
The Market
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Long
distance
telephony
Soft
PBX
Enterprise
multimedia
Public
multimedia
for
wireless
nerds?
Public
multimedia,
broadband
The market for real-time services over IP will evolve from the current
‘toll bypass’ market. In the long run it is about services and innovations!
(over a cheap infrastructure)
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Lill Kristiansen, Ericsson AS
‘Problems’
• High bandwidth, real-time media over IP
– need for ‘managed network’, QoS, accounting,...
• Locating other users
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– machine addresses and / or user-id’s
– users on PSTN (22 xx yy zz)
• Authenticating users
• Knowing other user's communication
capabilities
(full blown MM-PC or simple audio device?)
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Lill Kristiansen, Ericsson AS
Factors driving IP telephony
•
•
•
•
Innovation
Deregulation
Convergence
Standards
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All issues are important!
Focus in this talk is on the standard issues
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Lill Kristiansen, Ericsson AS
Ericsson policy on IP-telephony standards
• Standards are important!
– Ericsson active in H.323, Tiphon, IETF etc
– Ericsson active in inter-ops (IMTC, Tiphon others)
• Standardise what is needed! (only)
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– Standards are needed for inter vendor and inter
domain issues, including ‘roaming users’
– Allow for innovative, competitive services and
applications ‘on-top of’ or ‘along side’ the standards
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Lill Kristiansen, Ericsson AS
IP Telephony implementations /
IP Telephony standards
• CU-SeeMe
• ITU-T: H.323 suite
– IMTC: Interoperability efforts
• ETSI: TIPHON
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– Public case, interworking with legacy. ,mobility
– IETF wg: MMUSIC (SIP), IPtel,...
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Lill Kristiansen, Ericsson AS
Outline of the rest of the talk:
• Basics about H.323
– GK, GW, endpoints, MCU
– call and media/connection separation
• About ETSI Tiphon project
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– based on H.323 (with public voice focus)
– PC-phone, phone-PC, PC-PC + mobility
• SIP (IETF)
• Other standards (brief)
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Lill Kristiansen, Ericsson AS
ITU-T H.323 is ...
An ITU-T standard
For multimedia communication:
Audio (mandatory)
Video (optional)
Data (optional)
On packet-based networks…
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v.1 main target LAN environments (1 ‘zone’ only)
v.1. datacom initiative (now more mixed data+telecom)
H.323 is an evolving standard (v3 is coming soon)
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Lill Kristiansen, Ericsson AS
The H.323 umbrella
H.323
Network
control
H.225.0
Session
control
H.245
Media
coding
Gateways
H.246
Security
H.235
RAS
control
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Call
control
Real-time
transport
RTP
Video
coding
Audio
coding
H.26X
G.7XX
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Data
T.120
Suppl. S
H.450
(H.450 classical
standardised PBX-like
supplementary
services are optional)
Lill Kristiansen, Ericsson AS
H.323 Entities
Terminal
The “phone” supporting voice plus
optional video and data.
MCU
Multipoint Control Unit. Controlling
endpoints in a conference.
Mixing/ transcoding of media.
Connection to other networks such
as ISDN, B-ISDN and GSTN. Both
network and application
interworking.
A “network control point” for a part
of a H.323 network - zone.
Registration, Admissions and Call
Control server.
Gateway
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Gatekeeper
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Lill Kristiansen, Ericsson AS
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H.323 Network (1 zone, 1 GK shown)
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Lill Kristiansen, Ericsson AS
User Awareness - Authentication - Security
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• Make sure the
END USER is who
he claims to be...
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Lill Kristiansen, Ericsson AS
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H.323 Gatekeepers
• Call by alias, instead of machine addresses
– “Espen” vs “193.161.191.216”
– user/subscription oriented
• Administrate use of network bandwidth
• Managing network resources (gateways,
MCUs...)
• In v1: 1 GK 1 zone (user & bandwidth)
• Improvements coming: N zones, roaming etc.
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Lill Kristiansen, Ericsson AS
H.323: an evolving standard
• v1: mostly LAN oriented
many roundtrips, many TCP conn.
• v2: Adding ‘fast start’ and security
– products ‘hot from vendors’ spring ‘99
• v3 (ready May ‘99)
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• Inter-op test events are still important!
– ‘foilware’ standard claims are not enough
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Lill Kristiansen, Ericsson AS
Direct call alternative:
Endpoint 1
Endpoint 2
Gatekeeper 1
ARQ(1)
ACF/ARJ(2)
Setup(3)
Caller gets
contact address
of called party
from GK
Call proceeding(4)
ARQ(5)
ARQ to GK for
bandwidth
admission
ACF/ARJ(6)
Alerting(7)
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Connect(8)
RAS Messages
Call Signalling Messages
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Lill Kristiansen, Ericsson AS
Gatekeeper routed call alternative
GK handles (user) registration and call setup
(opt. Including user/call related value added services)
Registatipn
phase
Endpoint 1
Endpoint 2
G at ek eep er 1
A RQ (1 )
A CF(2 )
Setu p (3 )
Setu p (4 )
Cal l P ro ceed in g (5 )
Cal l P ro ceed in g (5 )
Call setuphase
A RQ (6 )
A CF/ A RJ(7 )
A lert i n g (8 )
A lert i n g (8 )
ARQ may be
‘pregranted’
I.e. GK may
allow for
incoming
calls during
registration
phase
(decreases
the call
setup time)
Co n n ect(9 )
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Co n n ect(1 0 )
RA S Mes sag es
Cal l Sig n al li n g Mess ag es
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Lill Kristiansen, Ericsson AS
Signaling: 2 gatekeepers routing, unknown B
party
E n d p o in t 1
Gatekeeper 1
Gatekeeper 2
E n d p o in t 2
A R Q (1 )
LR Q (2 )
LC F (3 )
A C F (4 )
S e t u p (5 )
S e t u p (6 )
C a ll P ro c e e d in g (7 )
S e t u p (8 )
C a ll P ro c e e d in g (7 )
C a ll P ro c e e d in g (7 )
A R Q (9 )
A C F (1 0 )
A le rt in g (1 1 )
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C o n n e c t (1 4 )
A le rt in g (1 1 )
A le rt in g (1 1 )
C o n n e c t (1 2 )
C o n n e c t (1 3 )
RA S M e s s a g e s
M u lt ic a s t R A S M e s s a g e s
C a ll S ig n a llin g M e s s a g e s
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Lill Kristiansen, Ericsson AS
ETSI Tiphon project
http://www.etsi.fr/TIPHON/TIPHON.htm
• focus on interworking with PSTN/PISN
– GW component specifications
– scalability (public case)
– inter-domain issues
• mobility and wireless aspects (just started)
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– incl.: user mobility, service mobility, terminal mob.
– wireless specifics (reuse of radio specs.)
• based (mostly) on H.323 on the IP side
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Lill Kristiansen, Ericsson AS
Mobility added
Scenarios- phases
Scenario 1
IP baserad
abonnent
(PC - Phone)
Scenario 2
PSTN
abonnent
PSTN
abonnent
PSTN
abonnent
IP
(Phone - Phone)
Scenario 4
IP baserad
abonnent
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(PC - PC via PSTN)
Scenario 0
(PC - PC)
IP baserad
abonnent
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W
E
A
R
E
IP baserad
abonnent
(Phone - PC)
Scenario 3
Phase 1 Phase2 Phase 3
PSTN
IP
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PSTN
abonnent
IP baserad
abonnent
IP baserad
abonnent
H
E
R
E
S
P
R
I
N
G
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Lill Kristiansen, Ericsson AS
Goals
• Work quick: Meetings every 2nd month, using e-mails in between
• Work smart: Do not reinvent the wheel: Use existing standards where existing
(IETF eller ITU-T protocols whereever possible)
• Work global: Not a European standard
(every 3rd meeting in America, next in Bankok in May)
• Based on H.323 series and existing SCN/PSTN standards
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• Application based solutions that can be used by different types of operators
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Lill Kristiansen, Ericsson AS
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Tiphon workgroups
•
•
•
•
•
•
•
Wg1 Requirements
Wg2 Architecture
Wg3 Protocols
Wg4 Addressing, naming
Wg5 Speech Quality and QoS
Wg6 Testing
Wg7 Mobility and wireless aspects (new)
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Lill Kristiansen, Ericsson AS
Tiphon Phase 2 architecture
DTS 03003,
Annex G/H.323
DTS 03004
GK
GK
D
G
BacK End/
clearing house
DTS 03005
A
C
H.323 (MM) client
PC or H.323 telephone
Media GW
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Specifikations
and reports phase 2
Requirement
Architecture:
GK - GK:
Basic call:
Security:
Addressing:
Quality:
Testspec.:
DTR 01002
TS 101313 (finished)
DTS 03003
DTS 03005
DTS 03006
DTS 04002
DTR 05001
DTR 06004
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Controller
N
B
F
J
Signalling
E.b
GW
PSTN
The protocols internal to
the PSTn GW are not finished
Media GW
E.a
Decomposed GW to PSTN
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Lill Kristiansen, Ericsson AS
’Number’ translation needed
Wireless
PSTN (or Private SCN)
GW
GW (FFS)
+999 1234 5678
Public
Enterprise
TIPHON
System
Tiphon
System
Gatekeepers
Public
Tiphon
Systems
(multiple
domains)
[email protected]
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IP
access
(best
effort)
IP Net
[email protected]
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Lill Kristiansen, Ericsson AS
Solutions(?) To be studied by Tiphon:
– New ’global country code’ ( e.g. 999)
proposed in Tiphon (awaiting ITU decision)
• may indicate IP-technology
• or global MM roaming service
– similar to Nextel 850 ’Interfon’ service inside Norway
– ’user@domain’ like user names
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– indicating home-GK
(HLR/Home-agent/SIP like solution)
– IP addresses (or ’temporary routing numbers’)
for media routing
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Lill Kristiansen, Ericsson AS
Quality classes for TIPHON System
4 (Best)
TIPHON speech quality
Eqivalent or
better than
G.711
One way delay
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Call
setup
times
<150 ms
Direct IP
addressing
(SCN) E.164
translation to
IP-address
(SCN) E.164 to
IP-address via
clearinghouse
or roaming
Email alias
translated
to IP-address
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3 (Hight)
2 (Medium)
Eqivalent or
better than
G.726
Eqivalent or
better than
GSM-FR
<250 ms
<450 ms
<1.5 s
<4 s
<7s
<2 s
<5 s
<10 s
<3 s
<8 s
<15 s
<13 s
<25 s
<4 s
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1 (Best effort)
Lill Kristiansen, Ericsson AS
SIP (Session Initiation Protocol)
IETF RFC-2543 for ‘invitations’ (call setup) to
multimedia sessions
• Lightweight Text based, HTTP-like
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– Request / Response
– extensible
•
•
•
•
Using UDP (and resending if needed)
Invite to SIP://user@domain + SDP for media
Does not address bandwidth/QoS
Does not address interworking with PSTN
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Lill Kristiansen, Ericsson AS
EN/FAD 109 0015
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Lill Kristiansen, Ericsson AS
EN/FAD 109 0015
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Lill Kristiansen, Ericsson AS
EN/FAD 109 0015
H.323 vs SIP
Analyse your needs and business case(s)
H.323
SIP
• Heavy (ANS.1 based)
• Operator can control the
network (and bandwidth
use)
• GK may use a service
node on top
• Off the shelf products
– for PC-PC cases
– and GW with legacy
• Simple implementation
• Network resources out of
scope
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• May control incoming calls
(invite + opt. CPL)
• Some prototypes
• Just passed as RFC-2543
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Lill Kristiansen, Ericsson AS
Other standards/consortium initiatives
– IPtel (WG in IETF)
– click-to-dial etc. (‘from web-to-POTS’)
– does not address ‘media-over-IP’ (yet?)
– CPL Call Processing Language (IETF)
– ongoing: standardising a language for call control
– Parlay for a Call-Control API (www.parlay.org)
– a demo held, no products (yet?)
– TINA-C (www.tinac.com)
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– lots of specification during 5 years, no products (yet?? )
– others?
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+ all the proprietary stuff
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Lill Kristiansen, Ericsson AS
What about the new services?
• H.450: Mixing service- and call control
Gatekeeper
Terminal
Service Control
Call Control
Call Control
Media Control
Media Control
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Service Control
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Lill Kristiansen, Ericsson AS
Example of services (requirement input to Tiphon)
From Tipia (www.tipia.org)
(service operator consortium)
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• Global credit card service
• CUG (closed user group) between
operators
• VPN (Virtual Private Network)
between operators
• Virtual Home Environment
• Universal roaming
• Global directory service
• Voice controlled mail box
Classical
supplementary
services (H.450 based)
• Call forward busy
• Call forward
unconditional
• Call waiting
• Call transfer
• More to come ...
(PBX based)
Other services? Need for standards? What can (not) be solved by VHE?
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Lill Kristiansen, Ericsson AS
Dissected gatekeeper and mobility (VHE)
Visiting domain
Home domain
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Services
Services
User data
User data
Network:
Network:
Terminal:
Roaming user
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Lill Kristiansen, Ericsson AS
Services and mobility
VHE (Virtual Home Environment) concept, (input to Tiphon)
The user may log on from everywhere.
Services
Visited GK controls his own resources
User/
subscriber
database
The visited GK contacts home GK’n and routes the call (but not
necessarily the media) via home GK.
 The user have accesses to the same services as when being ‘at home’
No time consuming process of standardising services is needed
Home GK
Allowing competitive service provisioning, innovation.
No need to standardise and transfer service profiles
Registration via visiting GK to home GK
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Visited GK
All incoming calls goes via home_GK (‘similar’ to GSM-HLR/SCP)
Also oiutgoing calls goes via home GK.
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Lill Kristiansen, Ericsson AS