Standards First!™. Fall Forum - Seattle, Washington - October 2001 H.450 Supplementary Services for H.323 Systems Karl Klaghofer Siemens AG Standards

StandardsFirst!™

Fall Forum - Seattle, Washington - October 2001Fall Forum - Seattle, Washington - October 2001

H.450 Supplementary Services H.450 Supplementary Services for H.323 Systemsfor H.323 Systems

Karl Klaghofer

Siemens AG

StandardsFirst!™

StandardsFirst!™Fall Forum - Seattle, Washington - October 2001Fall Forum - Seattle, Washington - October 2001

ContentsContents

Scope of H.450 Architecture Example call flows Gateway Interworking Standardization aspects Summary


Scope (1) – What is H.450 about ?Scope (1) – What is H.450 about ? ITU-T umbrella standard for Telephony / Multimedia ITU-T umbrella standard for Telephony / Multimedia

supplementary services for H.323 systems,supplementary services for H.323 systems,

for features that need signalling over the IP network beyond what for features that need signalling over the IP network beyond what is defined within H.323 base signalling protocolis defined within H.323 base signalling protocol

Examples: Three Party Services Call Redirection Services Team Function Services Unsuccessful Call Services Attendant related services …


Scope (2) - H.450 as “Building blocks”Scope (2) - H.450 as “Building blocks”for Applicationsfor Applications

Examples: Call Center, Automatic Call Distribution (ACD)

Using Call Transfer service to redirect calls from the ACD server to an ACD agent

Use Call Intrusion/silent monitoring service for ACD supervisor services

Multimedia Messaging Use of Call Diversion service to forward to Messaging Center Use Message Waiting Indication service by Messaging Center

to notify the served user Integration with other Applications

Integrate with E-Mail Integrate with world of organizers (e.g. calendar based call

diversion)


H.450 SignallingFE FE

IP / H.323

Architecture (1) - PrinciplesArchitecture (1) - Principles Functional, symmetrical Protocol derived from ISO “QSIG” protocol, optimized for

IP/H.323 environment Independent of type of network (Private or Carrier) Media independent Flexible in architecture:

Fully distributed modelFully distributed modelIntelligent endpoints supporting H.450; network transparent for H.450 -> the Internet/Intranet paradigm

Centralized modelCentralized modelH.450 as the networking feature protocol -> the traditional telephony model

EP Gatekeeper / Proxy EP

Gatekeeper / Proxy

Endpoint Endpoint

FE Functional Entity


Architecture (2) – Example Architecture (2) – Example H.450 Endpoints & EntitiesH.450 Endpoints & Entities

IP / H.323 Network

Soft client

Soft client IP Phone

Server Endpoints- Group Features- Proxies

H.450 Signalling

Gatekeeper / Proxy

Stimulus EP

GWY/BS to Wireless GSM, W-LAN, Bluetooth,...

Fax

Gateway(to QSIG, ISDN,…)


Architecture (3) – Architecture (3) – H.450 in H.323 Protocol ModelH.450 in H.323 Protocol Model

G.7xx

RTP

RTCP

H.225.0

H.245

Unreliable Transport (UDP) Reliable (TCP)

Network Layer (IP)

Applications

H.26x

H.225RAS

…

H

.45

0.3

H

.45

0.2

H.450.1


H.225.0(Q.931)

IE's

Allows for Manufacturer specific extensions using Object Identifier that indicate the manufacturer

User-user IE (H323-UU-PDU)H450 Supplementary Service Component

NFE IH.450Feature 1

H.225.0 message (e.g. SETUP)

TCP/IP packet

h323-message-body

Service APDUs

e.g. Setup-UUIE:Fast Start, Endpoint type, Source Address, Dest Address, ...

Architecture (4) – Architecture (4) –

H.450 Signaling within H.323 messagesH.450 Signaling within H.323 messages

H.450Feature 2

Ext Proprietary “H.450 like” feature 3

How to to react if not understood ?-Ignore-Reject-Clear call

Destination of the Feature ?- endpoint- any entity- a specific one


EP AEP B

Example Call Flows (1) – Example Call Flows (1) – Single Step Transfer (H.450.2)Single Step Transfer (H.450.2)

EP C

FACILITY ctInitiate (addressC,..)

SETUP ctSetup (TransferNbA,..)

CONNECT ctSetup.Res

REL COM ctInitiate.Res

Active Call

Active call

Idle


EP A EP B

Example Call Flows (2) – Example Call Flows (2) – Automatic Callback on Busy (H.450.9)Automatic Callback on Busy (H.450.9)

Active Call

SETUP (ccbs)

RELEASE COMPLETE (ccbs.Result)

• Monitoring User B phase

SETUP (ccExecPossible)

A called B – B met busy

• B becomes available

ALERT / CONNECT

SETUP (ccRingout)

RELEASE COMPLETE


A

Example Call Flows (3) – Example Call Flows (3) – Call Pickup Group w/Pickup Server (H.450.5)Call Pickup Group w/Pickup Server (H.450.5)

B

C

D

Pickup Group Server

FACILITYpickup

groupNotification (pickup address B,callingUserA, pickupId,…)

SETUP (pickRequ, pickupID)

SETUPpickExe.invCONNECT

pickExe.Res

Active Call

SETUP

ALERTING

Alerting

SETUP(groupNotification)


Gateway Interworking (1) - OpportunitiesGateway Interworking (1) - Opportunities

Opportunity for Gateway Interworking of H.323/H.450 Features with corresponding Features of other networks/systems for end-to-end feature operation in inhomogeneous networks:

PBX interworking:PBX interworking: QSIG, DPNSS, Proprietary PBX protocols

Public Network interworking:Public Network interworking: DSS1 US ISDN Protocols (NIx) SS7

Interworking with Non-H.323/H.450 VoIP systems:Interworking with Non-H.323/H.450 VoIP systems: SIP


Gateway Interworking (2) – Example QSIG GWYGateway Interworking (2) – Example QSIG GWY

H245H.225.0

TCP UDP

IP

MAC ISDN

QSIG H.323 / H.450

Voice

G.7xx

RTP

IPMAC

G.7xx

UDPIP

MAC

G.711

B-Channel B-Channel

G.711

ISDN

UDP

RTP

User Plane

Control Plane

QSIG Basic call

QSIG Suppl Service

QSIG GF

Gateway interworking

Gateway interworking

D-channel

QSIG Basic Call

D-channel

QSIG GF

QSIG Suppl Service

Voice

H450.1

H450.X

H245

H.225.0TCP UDP

IP

MAC

H450.1

H450.X • H.450 based on QSIG concepts

• Corresponding functions in both worlds allows easy interworking

• Smooth migration from SCN to IP

• Features available End-to-end between LAN and PBX

H.323/H.450 Gateway IP/LAN

PBXPBX


Gateway Interworking (3) – What about SIP ?Gateway Interworking (3) – What about SIP ?

Internet drafts available for H.323 – SIP Interworking for Basic Call; with first products available on the market

Desire for Interworking between H.323 and SIP also on Supplementary Services level – first candidates:

IETF Work item: SIP Call Transfer Further SIP drafts available: MWI, Call Diversion, etc.

Supplemen-tary

Service IW

Basic Call IW

H.323/H.450 VoIP System

SIP VoIP System

H.450 SIP SS

H.323 SIP BC

H.323-SIP Gateway


Standardization – MethodsStandardization – Methods

All Standards of the H.450 series of ITU-T Recommendations follows the same, consistent method of specification:

Stage 1 Service Description – Users Perspective Stage 3 Service Description – Procedures, Interactions Call Flow Diagrams Generic API definition Syntax definition (ASN.1) SDLs

High degree of interoperability between different implementationsHigh degree of interoperability between different implementationscan be expectedcan be expected


Standardization – Status (1) Standardization – Status (1)

Published ITU-T SG16 H.450.x standards – 12 Recommendations that cover more than 25 key features12 Recommendations that cover more than 25 key features:

H.450.1 Generic Functions (Framework, base methods)H.450.1 Generic Functions (Framework, base methods) Call Related & Call independent H.450 signalling Remote Operation Service - ROS (Invoke, Return Result, Return Error, Reject) Action Indicator (i-apdu) Adressed entity (NFE) Manufacturer Specific Information Extension Mechanism (MSI)

H.450.2 Call Transfer for H.323H.450.2 Call Transfer for H.323 Single Step Transfer (w/o Consultation) Transfer w/ Consultation Transfer into Ringing/Active

H.450.3 Call Diversion for H.323H.450.3 Call Diversion for H.323 Call Forwarding Unconditional (CFU) Call Forwarding on Busy (CFB) Call Forwarding on No Reply (CFNR) Call Deflection (CD)


Standardization – Status (2) Standardization – Status (2)

H.450.4 Call Hold for H.323H.450.4 Call Hold for H.323 Near End Hold Remote End Hold

H.450.5 Call Park and Call Pickup in H.323H.450.5 Call Park and Call Pickup in H.323 Directed Park / Directed Pickup Group Park / Group Pickup Call Pickup Groups

H.450.6 Call Waiting in H.323H.450.6 Call Waiting in H.323 H.450.7 Message Waiting Indication for H.323H.450.7 Message Waiting Indication for H.323

MWI Activation, Deactivation MWI Interrogation Message Waiting Callback (MWCB)

H.450.8 Names Identification in H.323H.450.8 Names Identification in H.323 Calling, Connected, Alerting, Busy Name Indication

H.450.9 Call Completion for H.323H.450.9 Call Completion for H.323 Call Completion on Busy (CCBS) Call Completion on No Reply (CCNR)


Standardization – Status (3) Standardization – Status (3) H.450.10 Call Offering for H.323H.450.10 Call Offering for H.323 H.450.11 Call Intrusion for H.323H.450.11 Call Intrusion for H.323

Intrusion / Break in at Busy User Silent Monitoring Recording

H.450.12 Common InformationH.450.12 Common Information Feature Capabilities Feature Control (do not hold, do not transfer, call type...) Party Category (user, attendant, ...)

H.450 is on the ITU-T SG16 work program also in its new study period (- 2004); i.e. further H.450.x Rec. will be added

Other standardization bodies H.450 activities: ECMA TC32

Published Interworking Standards for H.450.x – QSIG Interworking

ETSI Tiphon Published H.450 Protocol Implementation Profiles (PICS)


Open, standard feature protocol for H.323 based IP systems Multi-vendor interoperability

Flexible in Architecture Enables smooth migration from SCN to IP

Customer can determine its own speed of migration End-to-end feature availability between SCN and IP systems during

migration phase via Gateway Interworking

Allows to distinguish from competitors Standard Manufacturer Specific Escape mechanism for proprietary add-

ons to standardized H.450 signalling

H.450 as application enabler

SummarySummary


Thank You !Karl Klaghofer

Siemens AG

([email protected])

Documents

Standards First!™. Fall Forum - Seattle, Washington - October 2001 H.450 Supplementary Services for H.323 Systems Karl Klaghofer Siemens AG Standards