Internet Telephony; -existing and emerging standards

1
Internet Telephony-existing and emerging
standards

• Lill Kristiansen, Ericsson AS
• Product Unit Internet
• Lill.Kristiansen_at_eto.ericsson.se
• www.ericsson.com/ipservices
• www.ericsson.com/gatekeeper

2
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 companys web
  pages, customer base, attendants, click-to-dial,
  email etc

3
The Market
Public multi-mediafor wirelessnerds?
Public multi-media, broadband
Enter-prisemulti-media
Long distance telephony
Soft PBX
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)
4
Problems

• High bandwidth, real-time media over IP
• need for managed network, QoS, accounting,...
• Locating other users
• machine addresses and / or user-ids
• users on PSTN (22 xx yy zz)
• Authenticating users
• Knowing other user's communication capabilities
  (full blown MM-PC or simple audio device?)

5
Factors driving IP telephony

• Innovation
• Deregulation
• Convergence
• StandardsAll issues are important! Focus in
  this talk is on the standard issues

6
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

7
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,...

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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)

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ITU-T H.323 is ...

• An ITU-T standard
• For 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
  datatelecom)
• H.323 is an evolving standard (v3 is coming soon)

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The H.323 umbrella
H.323
Session control H.245
Network control H.225.0
Gateways H.246
Media coding
Security H.235
RAS control
Suppl. S H.450
Video coding
Audio coding
Data
Call control
H.26X
G.7XX
T.120
(H.450 classicalstandardised PBX-like
supplementaryservices are optional)
Real-time transportRTP
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H.323 Entities
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H.323 Network (1 zone, 1 GK shown)
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User Awareness - Authentication - Security

• Make sure the END USER is who he claims to be...

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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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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

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Direct call alternative
ARQ to GK for bandwidth admission
Caller gets contact address of called party from
GK
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Gatekeeper routed call alternativeGK handles
(user) registration and call setup (opt.
Including user/call related value added services)
Registatipn phase
ARQ may be pregranted I.e. GK may allow for
incoming calls during registration phase
(decreases the call setup time)
Call setuphase
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Signaling 2 gatekeepers routing, unknown B party
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ETSI Tiphon project http//www.etsi.fr/TIPHON/TIP
HON.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

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Mobility added
Scenarios- phases
Phase2
WE ARE HERE SPRING 99
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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
• Application based solutions that can be used by
  different types of operators

22
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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Tiphon Phase 2 architecture
DTS 03004
G
GK
GK
D
BacK End/clearing house
A
C
F
H.323 (MM) clientPC or H.323 telephone
E.b
J
Media GW
Signalling
Controller
GW
PSTN
N
The protocols internal to the PSTn GW are not
finished
B
Media GW
E.a
Decomposed GW to PSTN
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Number translation needed
999 1234 5678
PublicTiphon Systems(multiple domains)
PublicTIPHON System
EnterpriseTiphon System
Gatekeepers
Lill.K-sen_at_eto.ericsson.se
IP access
(best effort) IP Net
Lill.K-sen_at_hotmail.com
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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_at_domain like user names
• indicating home-GK (HLR/Home-agent/SIP like
  solution)
• IP addresses (or temporary routing numbers) for
  media routing

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Quality classes for TIPHON System

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
lt150 ms lt250 ms
lt450 ms Call
Direct IP setup addressing
lt1.5 s lt4
s lt 7 s times
(SCN) E.164
translation to lt2 s
lt5 s
lt10 s IP-address
(SCN) E.164 to
lt3 s lt8 s
lt15 s
IP-address via
clearinghouse
or roaming Email
alias translated
lt4 s
lt13 s lt25 s
to IP-address

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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_at_domain SDP for media
• Does not address bandwidth/QoS
• Does not address interworking with PSTN

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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

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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

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What about the new services?

• H.450 Mixing service- and call control

Terminal
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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?
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Dissected gatekeeper and mobility (VHE)
Visiting domain
Home domain
Roaming user
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Services and mobility
VHE (Virtual Home Environment) concept, (input to
Tiphon)

• The user may log on from everywhere.
• Visited GK controls his own resources
• The visited GK contacts home GKn 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
Visited GK