internet telephony; -existing and emerging standards

28.04.99 Lill Kristiansen, Ericsson AS1

EN

/FA

D 1

09 0

015

Internet Telephony;-existing and emerging standards

Lill Kristiansen, Ericsson AS

Product Unit Internet

[email protected]

www.ericsson.com/ipservices

www.ericsson.com/gatekeeper


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

‘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?)


EN

/FA

D 1

09 0

015

Factors driving IP telephony

• Innovation• Deregulation• Convergence• Standards

All issues are important! Focus in this talk is on the standard issues


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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,...


EN

/FA

D 1

09 0

015

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)


EN

/FA

D 1

09 0

015

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)


EN

/FA

D 1

09 0

015

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)


EN

/FA

D 1

09 0

015

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.


EN

/FA

D 1

09 0

015

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)


EN

/FA

D 1

09 0

015

User Awareness - Authentication - Security

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


EN

/FA

D 1

09 0

015

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.


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


ARQ may be ‘pregranted’ I.e. GK may allow for incoming calls during registration phase

(decreases the call setup time)

Registatipn

phase

Call setuphase


EN

/FA

D 1

09 0

015

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)


Connect(13 )

Multicast RAS Messages


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

• 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


EN

/FA

D 1

09 0

015

Tiphon workgroups

• Wg1 Requirements

• Wg2 Architecture

• Wg3 Protocols

• Wg4 Addressing, naming

• Wg5 Speech Quality and QoS

• Wg6 Testing

• Wg7 Mobility and wireless aspects (new)


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

+999 1234 5678

PSTN (or Private SCN)

PublicTIPHONSystem

(best effort)IP Net

IP access

Gatekeepers

[email protected]

’Number’ translation needed

[email protected]

PublicTiphon Systems(multiple domains)

EnterpriseTiphon System

Wireless

GWGW (FFS)


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

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


EN

/FA

D 1

09 0

015

• 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?


EN

/FA

D 1

09 0

015

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?


EN

/FA

D 1

09 0

015

Dissected gatekeeper and mobility (VHE)

User data

Network:

Services

Terminal:

User data

Network:

Services

Roaming user

Visiting domain Home domain


EN

/FA

D 1

09 0

015

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

internet telephony; -existing and emerging standards

Documents