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www.netcentrex.NET
Enabling Next Generation Networks and ServicesEnabling Next Generation Networks and Services
SIP 2003
Olivier Hersent – CEO/CTO
2Document under NDA © 2002 NetCentrex S.A. All rights reserved.
AgendaAgenda
NetCentrex overview
What about SIP today ? Class IV domain advanced topics
Routing
Numbering Plan
Class 5 domain advanced topics Protocol discussion
SIP in NetCentrex products
4Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Office LocationsOffice Locations
NetCentrex, Inc Boston
NetCentrex, S.AParis, Headquarters
Caen, Core Switching R&DLyon, Service Node R&D
Paris, Contact Center R&D
NetCentrex,SL Madrid
NetCentrex, NV Brussels
German sales office
UK sales office
APAC sales office
NetCentrex, Inc San Jose
Italy sales office (Pending)
5Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Integration partners complement our direct presenceIntegration partners complement our direct presence
Hewlett-Packard / Compaq, WW partner presence
Atos Origin, European partner presence
Satec, Spain, Portugal, North Africa & South
America
Anect, Czech Republic, Slovakia
Comptek, Russia
AMT, Russia
CSSI, France
Dimension Data, worldwide partner presence
Coheris, European partner presence
Cap Gemini, WW partner presence
Sema, European partner presence
6Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Key figuresKey figures
160 employees, about 50% in R&D Over 150 customers
Despite the challenging environment, NetCentrex sales grew over 30% in 2002
NetCentrex has reached profitability in 2002
20002001
2002
Since 2000, NetCentrex is one of the fastest growing and most stable next-gen telecom manufacturer
7Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Key Achievements in
2002
Key Achievements in
2002
8Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Customer deploymentsCustomer deployments
Largest worldwide VoIP VPN deployment (Equant) Largest worldwide full VoIP Residential deployment
(Fastweb, 200K users, 1.5M calls/day) Largest worldwide SIP based hosted contact center
(Deutsche Telekom)
Massive deployments of the CAMEL Media Control Server in mobile networks at various service providers worldwide (through HP / Compaq)
10Document under NDA © 2002 NetCentrex S.A. All rights reserved.
SIP in 2002SIP in 2002
2002 is the year where things get back to reality:
Failure of major carriers, precisely those with the most ‘advanced’ SIP plans Demand is not so clear, volumes not there. Trials, trials, trials…
Failure of UMTS Basic UMTS pushed back years, advanced VoIP features hardly on the horizon Refocus of UMTS on traditional protocols
Explosion of the telecom bubble, leaving high skepticism on so-called “new applications” Focus on telephony for all major customers Virtually ALL IP-PBXs use H.323 exclusively XP SIP support did not bring any market explosion for carriers… where is the money
? Major changes of RFC 3261 over RFC 2543
Correction of major protocol design errors (PRACK, UPDATE) SIP is getting very complex, but the spec still has a quality problem SIP is controlled by to few companies. Not a healthy situation. Quality comes with
debates and a well defined standardization process.
11Document under NDA © 2002 NetCentrex S.A. All rights reserved.
New Public Network ArchitectureNew Public Network Architecture
Application Domain(Class V or other)
User Access Domain
VoIP Network EdgeDomain
VoIP Class IVDomain
Equipment located in the customer premises, access authentication equipment,
access management equipment
Residential gateway, Cable modem with VoIP, xDSL modem
with VoIP, IP Phone, Access Gatekeeper, SIP Registrar
Collocated equipment for added value applications : IP Centrex, Call Center, etc, and equipment for application usage reporting
VON softswitch, Class V softswitch, Contact Center
Application Server, announcement server, IVR, etc
Collocated equipment for basic and VoIP VPN call routing within
the VoIP network, and infrastructure management
Class IV softswitch, Directory Gatekeeper, Number portability
softswitch, etc
Interfaces with the PSTN and with other VoIP networks,
interdomain call detail reporting, Security equipment
Edge proxy, protocol converter, SS7 gateway, ISDN gateway,
trunking gateway, etc
13Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Network DiagramNetwork Diagram
VoIP PSTN GWs
Infra
NetCentrex CCS
E1s
SIP / H.323Network
Class 4/5
Soft IP-Phone
PSTN
SS7 Call Agents
MGCP/T
SS7
SAUSAU
H.323/SIP Phone
H.323 CPE POTS
Voice streams (RTP)
MGCP/L
Core N
W
MGCP CPE
POTS
MGCP IP Phone
H.323/SIP
14Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Key requirements of the SS7 edge functionKey requirements of the SS7 edge function
Must properly map ALL ISUP call scenarios (details follow)
Must be capable of ISUP encapsulation Must detect and implement out-of-band DTMF Must support a standard media flow reroute command (TCS=0,
Re-Invite) Must support the same FAX transport method as the core
network. Must support the voice coders used in the VoIP network Must support loop-back calls
If these requirements are met, regardless of the VoIP protocol (H.323, SIP), ALL telephony services can be built on the layers above
15Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Support of ALL ISUP call flowsSupport of ALL ISUP call flows
Announcements before connect Typical H.323 issue : no faststart or earlyH245 support Typical SIP issue : no PRACK support (reliable provisional
responses)
Announcements on release (Disconnect with PI /release/Release Complete) SIP and H.323 use only ONE release message
CLIR service H.323 must support octet 3a (v2 with extensions, or v3) Vendor specific in SIP, bug in the RFC spec.
Numbering plans, type of number… Not present in SIP, required by many PBXs
16Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Support of ISUP encapsulationSupport of ISUP encapsulation
H.323 already encapsulates almost all Q.931 elements (CLIP/CLIR, Type of Network, Type of Number, etc.)
SIP lacks almost all SS7 / Q931 parameters
H.323/H.246 = SIP/T = encapsulation of the ISUP message, undecoded, as a “black box”
GTD = Cisco proprietary, transport of ISUP decoded, potentially much more powerful (ISUP becomes visible to VoIP components)
For VoIP termination/origination, only Q.931 transparency is required. Full transparency required for SS7 toll bypass only.
17Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Support of media stream redirectionSupport of media stream redirection
A frequently forgotten requirement… unlike the TDM, VoIP routes media streams end to end.
Lack of this feature is a showstopper for all services
CallAgent IP-PBX
Phone A
Phone B
Media GW
MGCP-T
SIP / H.323
18Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Why out-of-band DTMF is important (1), prepaid exampleWhy out-of-band DTMF is important (1), prepaid example
MCSMCS
User ARTP
SIP Call control & signaling
Collect Destination, user Id and PIN code. Validate through WNP procedure
MCSMCS
User A User BRTP
Make call to other end and use Re-Invite to optimize RTP path
MCSMCS
User A User B
INFO msg ’#’
1 2
3 4
RTP
SIP bye
User presses ‘#’. Call is interrupted. IVR sequence restarts. User B disconnected
MCSMCS
User A User CRTP
User wants to call C. Make call to other end and use Re-Invite to optimize RTP path
19Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Why out-of-band DTMF is important (2)Why out-of-band DTMF is important (2)
5 10 20 50 100 200 300One way delay(ms)
0
10
20
30
40
50
TE
LR
(dB
)
30
1% complain about echo problems
10% complain about echo problems
Talker echo tolerance curves (G.131 figure 1)
Echo Cancellation G711 theoretical limitActual VoIP network echo cancellation
Delay with RTP tromboning
Delay without RTP tromboning
CCplatform
CCplatformThese numbers are for average residential
telephony users, and are probably much stricter for professional users, such as call center agents
20Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Out of band DTMF, the #1 issue in SIPOut of band DTMF, the #1 issue in SIP
All H.323 devices must support H.245 UII In SIP, there is no standard !
Most phones still use RTP encoded DTMF (RFC 2833), as well as many network devices
SONUS uses INFO messages, with a payload similar to UII NUERA uses INFO messages, with a MGCP like payload CISCO uses Subscribe/Notify (draft-mahy-sip-signaled-
digits-00.txt) (IOS 12.2.11(T)), or INFO (Cisco specific) New SIP RFC 3265 proposes yet another method
Out-Of-Band DTMF support in SIP is still mostly proprietary
21Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Conclusion on the network edgeConclusion on the network edge
SIP and H.323 are now exact equivalents for telephony: Nothing you can do in H.323 you cannot do in SIP Nothing you can do in SIP you cannot do in H.323
But SIP is still mostly proprietary for many features (ISUP transparency, out-of-band DTMF) OK for pure toll bypass applications, in a SINGLE vendor SS7 Call
Agent environment Creates complex issues in class 5 applications, or any application
linked to the enterprise. Critical choice of SIP enterprise side devices which must support same extensions as core (or use MGCP instead, with SIP conversion in the core network)
Very limited choice of SIP end user devices (most IP-PBX are still H.323 !)
22Document under NDA © 2002 NetCentrex S.A. All rights reserved.
The Class 4 Domain
H.323 and SIP
similarities
23Document under NDA © 2002 NetCentrex S.A. All rights reserved.
H.323 « Light » Class IV issuesH.323 « Light » Class IV issues
Originatinggateway
Direct ModeGK Terminating
gateway
3rd PtyPSTN network
PSTN CO
ARQ 123456789ACF @TGWSETUP 123456789
SETUP 123456789RELEASE (congestion)
RELEASE (congestion)
The Call is lost !But other PSTN parners may have been able
to complete the call.The network doe not improve call failure rate.
Failure rate50%
PerceivedNetworkFailure rate50%
24Document under NDA © 2002 NetCentrex S.A. All rights reserved.
SIP « Light » Class IV issuesSIP « Light » Class IV issues
Originatinggateway
SIPRedirect Server Terminating
gateway
3rd PtyPSTN network
PSTN CO
INVITE 123456789
503 Service UnavailableACK
SETUP 123456789
RELEASE (congestion)
INVITE 123456789
302 Moved (@TGW)ACK
Failure rate50%
PerceivedNetworkFailure rate50%
The Call is lost !But other PSTN parners may have been able
to complete the call.The network doe not improve call failure rate.
25Document under NDA © 2002 NetCentrex S.A. All rights reserved.
H.323 « True » Class IVH.323 « True » Class IV
Originatinggateway
TerminatingGateway 1…2
3rd PtyPSTN network
PSTN CO
SETUP 123456789RELEASE (congestion)
Now the Call is properly completed.True class IV resolves network congestion cases, both
in the VoIP network and in the PSTN.This allows to peer with less reliable PSTN partners, but
still offer the best call completion rates
CCS
SETUP 123456789SETUP 123456789
RELEASE (congestion)
SETUP 123456789CONNECT
CONNECT
Failure rate50%Failure rate
50%
Perceived Network Failure rate25%
26Document under NDA © 2002 NetCentrex S.A. All rights reserved.
SIP « True » Class IVSIP « True » Class IV
Originatinggateway
TerminatingGateway 1…2
3rd PtyPSTN network
PSTN CO
SETUP 123456789
RELEASE (congestion)
CCS
INVITE 123456789 INVITE 123456789
503 Service Unavailable
INVITE 123456789
200 OK200 OK
ACK
ACK ACK
Failure rate50%
Now the Call is properly completed.True class IV resolves network congestion cases, both
in the VoIP network and in the PSTN.This allows to peer with less reliable PSTN partners, but
still offer the best call completion rates
Perceived Network Failure rate25%
Failure rate50%
27Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Protocol convertersProtocol converters
The NetCentrex CCS PTU (Protocol Translation Unit) transcodes H.323 to SIP, and vice versa.
All telephony services are OK (including early media, media rerouting, etc.)
Requires true out-of-band DTMF on SIP side (OK Sonus/Nuera/Cisco)
29Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Class V in VoIP networksClass V in VoIP networks
Two paradigms :
Distributed smart endpoint approach : The endpoint (H.323 or SIP) supports multi-line features (call
waiting, etc), and the softswitch supports single line features (call redirections, accounting, blocking, etc)
This is the favored market approach today for residential (ATA180, most SIP&H.323 phones, etc), except in PAcketCable® environments
Centralized dumb endpoint approach (stimulus) MGCP/L endpoints, Softswitch does all Mainly useful for full Centrex features
30Document under NDA © 2002 NetCentrex S.A. All rights reserved.
NetCentrex approach to class VNetCentrex approach to class V
Because of the modular design of the softswitch Smart endpoint approach available today using the
Subscriber Policy Engine, compatible with a broad range of CPEs
Dumb endpoint approach can be added for selected customers (more IP Centrex type), using the add-on Subscriber Access Unit.
31Document under NDA © 2002 NetCentrex S.A. All rights reserved.
CCSSubscriber Policy Engine
User Access Domain
SIPSIP
Accounting Master Unit
Class 5 Call Control
NetCentrex Allows Native Support of H.323, SIP, and MGCPNetCentrex Allows Native Support of H.323, SIP, and MGCP
SIPRegistrar
SIPRegistrar
CentrelizedLDAP
Database
H.323H.323
SIPSIP
MGCP/LMGCP/L
H.323SIP
H.323SIP
V
AGKAGK
SAUSAU
H.323H.323
H.323SIP
H.323SIP
AccountingBilling
CoreDomain
32Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Which protocol for the
line control ?
33Document under NDA © 2002 NetCentrex S.A. All rights reserved.
CPE control protocols (1)CPE control protocols (1)
H.323 and SIP follow the ISDN philosophy of a “smart phone”.
This approach works well for residential, where the required feature set is local to one subscriber
This approach becomes very challenging when features involve a group of lines (park, pick-up, transfer, etc…), because it is hard to synchronize the state of multiple smart phones.
The PBX market has massively adopted stateless phones for this purpose
MGCP/L follows the stateless/stimulus philosophy
34Document under NDA © 2002 NetCentrex S.A. All rights reserved.
CPE control protocols (2)CPE control protocols (2)
MGCP/L provides the following advantages over H.323 and SIP for advanced class 5 functions:
Comprehensive support of analogue lines Possibility of implementing services on off-hook,
before the call is connected No impact of deployed devices on new services (all
services are 100% centralized) Business Phone Package allows customization of
feature activation buttons, and screen presentation (Hardcoded by the phone manufacturer in SIP and H.323)
35Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Redial PickUpNewCall More
12h50P 02/12/02 650 778 8125
Your current options
Business Phone packageBusiness Phone package
36Document under NDA © 2002 NetCentrex S.A. All rights reserved.
CPEs : Cost, Availability and Advanced ServicesCPEs : Cost, Availability and Advanced ServicesMGCP CPEs SIP CPEs H.323 CPEs
Availability yes yes Yes
Price per line (requested features : 3 way, transfers, basic screen control, user interaction capabilities)
Very tough competition (driven by packetcable demand)
Emerging competition Active competition
Can control analog phones
Yes WeakNo transfer, no off-hook services
WeakNo transfer, no off-hook services
Standards Stable, many vendors (packet cable, NCS)
Not stable (Centrex requires many proprietary messages)
Stable
Service capabilities
All services (100% controlled by network)
Restricted by phone. No “Off-Hook service” capabilities.
No out of band DTMF!
Restricted by phone. No “Off-Hook service” capabilities.
37Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Conclusion on CPE control protocols Conclusion on CPE control protocols
MGCP is more suitable for Centrex services: Full control of MGCP dumb terminals , screen control Off-hook services Rich services for analog phones (connected to CPE MGCP
Gateways: transfer, ) Easier management Easier introduction of new services
Terminal Competition driven by Cable deployments (MGCP/NCS) SIP is still used towards the network (or H.323)
But SIP / H.323 can be used for residential (if no control on off-hook services required)
39Document under NDA © 2002 NetCentrex S.A. All rights reserved.
Support for SIP in NetCentrex productsSupport for SIP in NetCentrex products
CCS softswitch SIP is supported since release 2.5 SIP/H.323 conversion is supported since release 3.0
MCS media control server and VXML browser SIP is supported since release 4 All features, including media anti-tromboning, are supported
SAGA hosted contact center SIP is supported in the current release
MyCall® residential application SIP is supported in the current release
VPN application SIP is supported in the current release
IPCentrex® business telephony application SIP is supported in the current release (trunk side, and soho)
40Document under NDA © 2002 NetCentrex S.A. All rights reserved.
SIP Instant MessagingSIP Instant Messaging
• The SIP “SIMPLE” Draft has been implemented, allowing CCS to be used as a routing node for instant messages.• VPN routing and alias transformations are properly handled for instant messages
• Instant messages are taken into account in the CCS CDRs, and can potentially be charged
• The Maestro IN service interface has been extended to support SIMPLE instant messages.
• Multiple modes are offered :• Fully routed mode for enhanced security and complete charging options• Cut-Through mode for enhanced scalability of accounting is not important
Instant Messaging has been fully tested with Microsoft Messenger®, in audio, video and file transfer modes.
41Document under NDA © 2002 NetCentrex S.A. All rights reserved.
PBX Site 2
CTI
Saga800 Contact Center UNEDIC: French unemployment administration
CTI
Customer Relationship
channels
Region1
Region2
AgentWorkstation
This is a killer app for VoIPand SIP !
Region 1
TelephoneNetwork Saga800
Contact Center
TelephoneNetwork
Architecture• 52 virtual call centers with 700 sites total• 1500 simultaneous agents logged on, 8000 total• 15 million calls/year• geographically distributed front-end and back-end architecture PBX Site 1
CTI
MobileMobile
TelephoneTelephone
42Document under NDA © 2002 NetCentrex S.A. All rights reserved.
NetCentrex Allows Native Support of H.323, SIP, and MGCPNetCentrex Allows Native Support of H.323, SIP, and MGCP
CONCLUSION:
Yes, There are good things in SIP !
… but SIP still has too much ‘bubble’ content (Remember WAP ?). A little less marketing and a little more thinking would help SIP become real.SIP still lacks some essential features and robustness.
Forget H.323, and you will forget the 2M+ H.323 ports sold per year (99% of the market). SIP and H.323 will have an equivalent market share only in 2 years.
NetCentrex does not worship protocols, we simply implement them as appropriate according to customer requirements. SIP is not always the best choice.