internet telephony; -existing and emerging standards
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28.04.99 Lill Kristiansen, Ericsson AS1
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Internet Telephony;-existing and emerging standards
Lill Kristiansen, Ericsson AS
Product Unit Internet
Lill.Kristiansen@eto.ericsson.se
www.ericsson.com/ipservices
www.ericsson.com/gatekeeper
28.04.99 Lill Kristiansen, Ericsson AS2
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Enablers for telephony over IP
• WEB explosion– user friendly GUIs, – IP as common denominator
• 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
28.04.99 Lill Kristiansen, Ericsson AS3
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The Market
Long distance telephony
Soft PBX
Public multi-media
for wirelessnerds?
Enter-prisemulti-media
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)
Public multi-media,
broadband
28.04.99 Lill Kristiansen, Ericsson AS4
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‘Problems’
• High bandwidth, real-time media over IP– need for ‘managed network’, QoS, accounting,...
• Locating other users – 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?)
28.04.99 Lill Kristiansen, Ericsson AS5
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Factors driving IP telephony
• Innovation• Deregulation• Convergence• Standards
All issues are important! Focus in this talk is on the standard issues
28.04.99 Lill Kristiansen, Ericsson AS6
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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)– 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
28.04.99 Lill Kristiansen, Ericsson AS7
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IP Telephony implementations /IP Telephony standards
• CU-SeeMe
• ITU-T: H.323 suite
– IMTC: Interoperability efforts
• ETSI: TIPHON
– Public case, interworking with legacy. ,mobility
– IETF wg: MMUSIC (SIP), IPtel,...
28.04.99 Lill Kristiansen, Ericsson AS8
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Outline of the rest of the talk:
• Basics about H.323– GK, GW, endpoints, MCU– call and media/connection separation
• About ETSI Tiphon project– based on H.323 (with public voice focus)– PC-phone, phone-PC, PC-PC + mobility
• SIP (IETF)• Other standards (brief)
28.04.99 Lill Kristiansen, Ericsson AS9
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ITU-T H.323 is ...An ITU-T standardFor multimedia communication:
Audio (mandatory)Video (optional)Data (optional)
On packet-based networks…
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)
28.04.99 Lill Kristiansen, Ericsson AS10
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The H.323 umbrella
H.323H.323
VideoVideocodingcoding
SessionSessioncontrolcontrolH.245H.245
NetworkNetworkcontrolcontrolH.225.0H.225.0
AudioAudiocodingcoding
RAScontrol
GatewaysGatewaysH.246H.246
Callcontrol
Real-timetransport
RTP
H.26X
SecuritySecurityH.235H.235
Suppl. SSuppl. SH.450H.450
G.7XX
MediaMediacodingcoding
DataData
T.120 (H.450 classicalstandardised PBX-like supplementaryservices are optional)
28.04.99 Lill Kristiansen, Ericsson AS11
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H.323 EntitiesTerminal The “phone” supporting voice plus
optional video and data.
MCU Multipoint Control Unit. Controllingendpoints in a conference.Mixing/ transcoding of media.
Gateway Connection to other networks suchas ISDN, B-ISDN and GSTN. Bothnetwork and applicationinterworking.
Gatekeeper A “network control point” for a partof a H.323 network - zone.Registration, Admissions and CallControl server.
28.04.99 Lill Kristiansen, Ericsson AS12
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H.320 VideoGateway
Internet
PSTN/ISDN
G.711
POTS
GSM
IP PhoneH.323
H.320
Multimedia TelephonyNetwork(H.323 over IP)
PSTN VoiceGateway
InternetFirewallRAS
Q.931H.245
RAS Q.931
H.245
RA
SQ
.931
H.2
45
RASQ.931
H.245RASQ.931
H.245
AudioVideoData
Au
dio
Vid
eo
Dat
a
Audio Video Data
Gatekeeper
MultipointControlUnit
H.323Client
H.323Client
Call signalling channels
Traffic channels
H.323 Network (1 zone, 1 GK shown)
28.04.99 Lill Kristiansen, Ericsson AS13
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User Awareness - Authentication - Security
• Make sure the END USER is who he claims to be...
28.04.99 Lill Kristiansen, Ericsson AS14
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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.
28.04.99 Lill Kristiansen, Ericsson AS15
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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)
• Inter-op test events are still important!– ‘foilware’ standard claims are not enough
28.04.99 Lill Kristiansen, Ericsson AS16
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Direct call alternative:
Endpoint 1 Endpoint 2
ARQ(1)
ACF/ARJ(2)
Setup(3)
Call proceeding(4)
Gatekeeper 1
Alerting(7)
Connect(8)
ARQ(5)
ACF/ARJ(6)
RAS Messages
Call Signalling Messages
ARQ to GK for bandwidth admission
Caller gets contact address of called party from GK
28.04.99 Lill Kristiansen, Ericsson AS17
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Gatekeeper routed call alternativeGK handles (user) registration and call setup (opt. Including user/call related value added services)
Endpoint 1 Endpoint 2
ARQ(1)
ACF(2)
Setup(3)
Alerting(8)
Call Proceeding(5)
Connect(10)
Gatekeeper 1
Setup(4)
Alerting(8)
Connect(9)
ARQ(6)
ACF/ARJ(7)
Call Proceeding(5)
RAS Messages
Call Signalling Messages
ARQ may be ‘pregranted’ I.e. GK may allow for incoming calls during registration phase
(decreases the call setup time)
Registatipn
phase
Call setuphase
28.04.99 Lill Kristiansen, Ericsson AS18
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Signaling: 2 gatekeepers routing, unknown B party
Setup(5 )
Setup(6 )
Alert ing(11 )
Setup(8 )
ARQ(1)
Call Proceeding(7 )
Call Proceeding(7 )
Call Proceeding(7 )
ACF(4 )
ACF(10 )
ARQ(9)
Alert ing(11 )Alert ing(11 )
Connect(12 )
RAS Messages
Connect(14 )
Endpoint 1 Endpoint 2Gatekeeper 1 Gatekeeper 2
LCF(3 )
LRQ(2)
Call Signalling Messages
Connect(13 )
Multicast RAS Messages
28.04.99 Lill Kristiansen, Ericsson AS19
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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)– incl.: user mobility, service mobility, terminal mob.– wireless specifics (reuse of radio specs.)
• based (mostly) on H.323 on the IP side
28.04.99 Lill Kristiansen, Ericsson AS20
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IP baserad abonnent
PSTNabonnent
Scenario 1(PC - Phone)
IP baserad abonnent
PSTN abonnentScenario 2
(Phone - PC)
IP PSTN
abonnent PSTNabonnent
Scenario 3(Phone - Phone)
PSTNIP baserad abonnent
IP baserad abonnent
Scenario 4(PC - PC via PSTN)
Scenarios- phases Phase 1 Phase2 Phase 3
IPIP baserad abonnent
IP baserad abonnent
Scenario 0(PC - PC)
WE
ARE
HERE
SPRING
99
Mobility added
28.04.99 Lill Kristiansen, Ericsson AS21
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• 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
• Application based solutions that can be used by different types of operators
Goals
28.04.99 Lill Kristiansen, Ericsson AS22
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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)
28.04.99 Lill Kristiansen, Ericsson AS23
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Requirement DTR 01002Architecture: TS 101313 (finished) GK - GK: DTS 03003Basic call: DTS 03005Security: DTS 03006Addressing: DTS 04002Quality: DTR 05001Testspec.: DTR 06004
Specifikations and reports phase 2
GK GK
Media GW
Controller
Media GW
Signalling
GW
N
D
A
B
C
J
E.a
E.b
BacK End/clearing house
F
G
Tiphon Phase 2 architecture
DTS 03005
DTS 03003, Annex G/H.323
DTS 03004
PSTN
Decomposed GW to PSTN
The protocols internal tothe PSTn GW are not finished
H.323 (MM) clientPC or H.323 telephone
28.04.99 Lill Kristiansen, Ericsson AS24
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+999 1234 5678
PSTN (or Private SCN)
PublicTIPHONSystem
(best effort)IP Net
IP access
Gatekeepers
Lill.K-sen@hotmail.com
’Number’ translation needed
Lill.K-sen@eto.ericsson.se
PublicTiphon Systems(multiple domains)
EnterpriseTiphon System
Wireless
GWGW (FFS)
28.04.99 Lill Kristiansen, Ericsson AS25
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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 – indicating home-GK
(HLR/Home-agent/SIP like solution)
– IP addresses (or ’temporary routing numbers’) for media routing
28.04.99 Lill Kristiansen, Ericsson AS26
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4 (Best) 3 (Hight) 2 (Medium) 1 (Best effort) TIPHON speech quality Eqivalent or Eqivalent or Eqivalent or better than better than better than
G.711 G.726 GSM-FR
One way delay <150 ms <250 ms <450 ms
Call Direct IPsetup addressing <1.5 s <4 s < 7 stimes (SCN) E.164 translation to <2 s <5 s <10 s IP-address (SCN) E.164 to <3 s <8 s <15 s IP-address via clearinghouse or roaming
Email alias translated <4 s <13 s <25 s to IP-address
Quality classes for TIPHON System
28.04.99 Lill Kristiansen, Ericsson AS27
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SIP (Session Initiation Protocol)
IETF RFC-2543 for ‘invitations’ (call setup) to multimedia sessions
• Lightweight Text based, HTTP-like– 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
28.04.99 Lill Kristiansen, Ericsson AS28
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28.04.99 Lill Kristiansen, Ericsson AS29
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28.04.99 Lill Kristiansen, Ericsson AS30
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H.323 vs SIPAnalyse your needs and business case(s)
H.323• 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
SIP• Simple implementation• Network resources out of
scope
• May control incoming calls (invite + opt. CPL)
• Some prototypes• Just passed as RFC-2543
28.04.99 Lill Kristiansen, Ericsson AS31
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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)– lots of specification during 5 years, no products (yet?? )
– others? + all the proprietary stuff
28.04.99 Lill Kristiansen, Ericsson AS32
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• H.450: Mixing service- and call control
Call Control
Service Control
Media Control
Call Control
Service Control
Media Control
Gatekeeper Terminal
What about the new services?
28.04.99 Lill Kristiansen, Ericsson AS33
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Example of services (requirement input to Tiphon)
From Tipia (www.tipia.org)
(service operator consortium)• 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?
28.04.99 Lill Kristiansen, Ericsson AS34
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Dissected gatekeeper and mobility (VHE)
User data
Network:
Services
Terminal:
User data
Network:
Services
Roaming user
Visiting domain Home domain
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The user may log on from everywhere.
Visited GK controls his own resources
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
Allowing competitive service provisioning, innovation.
No need to standardise and transfer service profiles
Registration via visiting GK to home GK
All incoming calls goes via home_GK (‘similar’ to GSM-HLR/SCP) Also oiutgoing calls goes via home GK.
VHE (Virtual Home Environment) concept, (input to Tiphon)
Services and mobility
Home GK
Services
User/subscriber database
Visited GK
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