The technology behind HD Voice has been around for quite some time, however, it is only in the last few years that it has gained the momentum needed to succeed and become ubiquitous.
This whitepaper discusses the technology behind HD Voice and sets out why it is an
important feature to consider when choosing your next communications platform.
The technology behind HD Voice has been around for quite some time, however, it is only in the last few years that it has gained the momentum needed to succeed and become ubiquitous.
This whitepaper discusses the technology behind HD Voice and sets out why it is an
important feature to consider when choosing your next communications platform.
Grokking TechTalk #18B: VoIP Architecture For TelecommunicationsGrokking VN
Bài talk chia sẻ kiến thức, kinh nghiệm về kiến trúc VoIP cho các bạn dự định xây dựng hệ thống dựa trên nền tảng VoIP, lập trình phát triển ứng dụng CRM, ERP, POS...tích hợp Call & Contact Center, ứng dụng OTT tích hợp Mobile App và call out PSTN, tương tự dịch vụ Viber Out:
- VoIP Platform
- IP-PBX
- WebRTC Gateway & Client
- Use Cases
About Speaker:
Anh Đạt là cử nhân Toán - Tin học, Thạc sỹ Tài chính - Ngân hàng, hơn 10 năm kinh nghiệm triển khai hệ thống ERP/CRM trên nền tảng Oracle/SAP và triển khai các dịch vụ giá trị gia tăng trên nền viễn thông, Brand Name SMS, Call & Contact Center, VoIP Platform
We live in the age of the digital packet. Documents, images, music, phone calls all get chopped up, propelled through networks, and reassembled at the other end according to Internet protocol. So why not TV? Today, IPTV (Internet Protocol Television) is creating headlines all over the world. This mass publicity is the result of numerous instances and stories depicting its humble deployments and its future. IPTV is a very useful system, through which you can receive both TV and video signals along with other multimedia services by means of your Internet connection. In nutshell, it is nothing but a broadband connection and a system to deliver various programs of television using the Internet protocol (i.e., language) over computer networks. It is important to remember that IPTV is not like any ordinary television program broadcast through the Internet, but rather it is unique in itself. Its contour is represented by a closed, proprietary TV system which is similar to the cable services present today. But, in contrast, the delivery of IPTV is made via IP-based secure channels, which result in a sharp increase in content distribution control.
It is important to remember that IPTV is not like any ordinary television program broadcast through the Internet, but rather it is unique in itself. Its contour is represented by a closed, proprietary TV system which is similar to the cable services present today. But, in contrast, the delivery of IPTV is made via IP-based secure channels, which result in a sharp increase in content distribution control.
Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks.
VoIP is one of a family of internet technologies and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks.
FB: https://www.facebook.com/mstfahsin
VoIP is short for Voice over Internet Protocol. VoIP is a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN.
Internet protocol (VoIP) is the technology of digitizing sound, compressing it, breaking it up into data packets, and sending it over an IP network.The conventional technique used for sending voice is PSTN (public switched telephone network) . As data traffic has higher speed than telephone traffic, so what we do most of the time we prefer to send voice over data networks. Voice over internet protocol (VoIP) is a method of telephone communication over a data network.
This article gives an overview of the Open IPTV Forum, whose aim is to
work out a future-proof standard for evolving IPTV services. The authors
summarize the main features and requirements addressed by the Open
IPTV Forum and present Ericsson’s take on how some of the challenges
raised by the forum ought to be resolved.
Grokking TechTalk #18B: VoIP Architecture For TelecommunicationsGrokking VN
Bài talk chia sẻ kiến thức, kinh nghiệm về kiến trúc VoIP cho các bạn dự định xây dựng hệ thống dựa trên nền tảng VoIP, lập trình phát triển ứng dụng CRM, ERP, POS...tích hợp Call & Contact Center, ứng dụng OTT tích hợp Mobile App và call out PSTN, tương tự dịch vụ Viber Out:
- VoIP Platform
- IP-PBX
- WebRTC Gateway & Client
- Use Cases
About Speaker:
Anh Đạt là cử nhân Toán - Tin học, Thạc sỹ Tài chính - Ngân hàng, hơn 10 năm kinh nghiệm triển khai hệ thống ERP/CRM trên nền tảng Oracle/SAP và triển khai các dịch vụ giá trị gia tăng trên nền viễn thông, Brand Name SMS, Call & Contact Center, VoIP Platform
We live in the age of the digital packet. Documents, images, music, phone calls all get chopped up, propelled through networks, and reassembled at the other end according to Internet protocol. So why not TV? Today, IPTV (Internet Protocol Television) is creating headlines all over the world. This mass publicity is the result of numerous instances and stories depicting its humble deployments and its future. IPTV is a very useful system, through which you can receive both TV and video signals along with other multimedia services by means of your Internet connection. In nutshell, it is nothing but a broadband connection and a system to deliver various programs of television using the Internet protocol (i.e., language) over computer networks. It is important to remember that IPTV is not like any ordinary television program broadcast through the Internet, but rather it is unique in itself. Its contour is represented by a closed, proprietary TV system which is similar to the cable services present today. But, in contrast, the delivery of IPTV is made via IP-based secure channels, which result in a sharp increase in content distribution control.
It is important to remember that IPTV is not like any ordinary television program broadcast through the Internet, but rather it is unique in itself. Its contour is represented by a closed, proprietary TV system which is similar to the cable services present today. But, in contrast, the delivery of IPTV is made via IP-based secure channels, which result in a sharp increase in content distribution control.
Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks.
VoIP is one of a family of internet technologies and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks.
FB: https://www.facebook.com/mstfahsin
VoIP is short for Voice over Internet Protocol. VoIP is a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN.
Internet protocol (VoIP) is the technology of digitizing sound, compressing it, breaking it up into data packets, and sending it over an IP network.The conventional technique used for sending voice is PSTN (public switched telephone network) . As data traffic has higher speed than telephone traffic, so what we do most of the time we prefer to send voice over data networks. Voice over internet protocol (VoIP) is a method of telephone communication over a data network.
This article gives an overview of the Open IPTV Forum, whose aim is to
work out a future-proof standard for evolving IPTV services. The authors
summarize the main features and requirements addressed by the Open
IPTV Forum and present Ericsson’s take on how some of the challenges
raised by the forum ought to be resolved.
la voix sur IP est clairement la voix dominante de l'avenir il existe beaucoup des applicatifs VoPI offrant des prestations correctes mais ces derniers vont énormément évoluer dans les années à venir en raison de la montée en puissance des débits de plus en plus impotants proposés sur les réseaux locaux et sur l'internet .
Formation complète ici:
http://www.alphorm.com/tutoriel/formation-en-ligne-cisco-ccna-icnd2-examen-200-101
La formation Cisco ICND2 apporte des connaissances et compétences nouvelles de celles que vous auriez pu découvrir lors de la formation Cisco ICND1. Les deux formations Cisco ICND1 et ICND2 vous préparent à la certification CCNA.
En effet, cette deuxième partie élargit les domaines de savoir-faire quant à l'élaboration d'un réseau d'entreprise de taille importante.
Au niveau du LAN, les participants sauront mettre en œuvre un réseau commuté utilisant des VLANs, pourront utiliser au mieux l'adressage IP par les techniques VLSM.
Les technologies WAN et la sécurité sont aussi largement évoquées lors de cette formation Cisco ICND2, notamment avec les protocoles PPP, Frame-Relay, le NAT, les listes de contrôle d'accès (ACL)...
A l'issue de la formation Cisco ICND2, les participants ont toutes les clés en main pour se préparer efficacement au passage de l'examen ICND2 et devenir ainsi être certifié Cisco CCNA.
Vous pouvez télécharger toutes les ressources Cisco Packet tracer et GNS3 liées à cette formations.
Practical Fundamentals of Voice over IP (VoIP) for Engineers and TechniciansLiving Online
This manual provides solid practical advice on application, implementation and, most importantly, troubleshooting Voice Over IP (VOIP) systems.
MORE INFORMATION: http://www.idc-online.com/content/practical-fundamentals-voice-over-ip-voip-21?id=151
This research work investigates and improves the performance of Voice over Internet Protocol (VoIP) traffic using IPV4 and IPV6 over WiMAX networks and the impact of various voice codec schemes and statistical distribution for Voice over Internet Protocol (VoIP) over WiMAX has been investigated in detail.
The objective of study is to guarantee QoS for multiple service class traffic in a multiple connection environment and to examine a case of QoS deployment over a cellular WiMAX network. In particular, the thesis compares the performance how much bandwidth for voip
In this white paper, VoIP for Beginners, you’ll be introduced to how VoIP works.
Discover what occurs when a VoIP call is placed and received
Understand the key technical terms and learn the issues that affect bandwidth and call quality Learn three issues to consider when defining VoIP call quality
Technology Update: Future of Broadcast according to EBU 2017Media Perspectives
De presentatie van Egon Verharen over de 'Future of Broadcast according to EBU'. De presentatie werd gegeven tijdens de Technology Update op donderdag 7 september. Organisatie: iMMovator
Voice over IP (VoIP) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms commonly associated with VoIP are IP telephony, Internet telephony, broadband telephony, and broadband phone service.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!SOFTTECHHUB
As the digital landscape continually evolves, operating systems play a critical role in shaping user experiences and productivity. The launch of Nitrux Linux 3.5.0 marks a significant milestone, offering a robust alternative to traditional systems such as Windows 11. This article delves into the essence of Nitrux Linux 3.5.0, exploring its unique features, advantages, and how it stands as a compelling choice for both casual users and tech enthusiasts.
GridMate - End to end testing is a critical piece to ensure quality and avoid...ThomasParaiso2
End to end testing is a critical piece to ensure quality and avoid regressions. In this session, we share our journey building an E2E testing pipeline for GridMate components (LWC and Aura) using Cypress, JSForce, FakerJS…
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
1. Profoss oct. 2007 - 1
AWTwww.awt.be
VOIP & Asterisk introductionVOIP & Asterisk introduction
ir. Zaccone Carmelo
Expert en Télécommunications et Technologies de l'Information
Agence Wallonne des Télécommunications www.awt.be
Avenue de Stassart, 16 Tél.: +32 81 77.80.76
B-5000 NAMUR www.linkedin.com/in/zaccone
Professional users of Free & Open Source Software
October 9 & 10 2007: Asterisk and VoIP Event
3. Profoss oct. 2007 - 3
AWTwww.awt.be
AWT in a nutshell:AWT in a nutshell:
an agency of thean agency of the
Belgian Walloon GovernmentBelgian Walloon Government
Convergence and diffusion center for ICT in the
Walloon Region of Belgium (« all online» strategy). The
AWT produces, gathers and federates ICT contents and
services.
The portal is at the same time a project of contents
and a technical demonstration
The AWT has huge knowledge in the fields of online
publication and information dissemination
ICT reference Newsletter (size 9-10k)
AWT Portal : 3,5 millions pages seen/year (be 66%, fr
19%, us 1%, ca 2%, other fr 10%,rest 2%)
4. Profoss oct. 2007 - 4
AWTwww.awt.be
AWT, an agency of theAWT, an agency of the
Belgian Walloon GovernmentBelgian Walloon Government
Observatory
and ICT
diagnostic
center
Technology &
Legal
watch center
Service center
for the
enterprises of
the ICT sector
Information
Collaboration
Leadership
Portal www.awt.be
Main diffusion channel of
the AWT services
Participation
(conference, fair,
workshop, …)
government (RW), public sector, entreprise, citizen, etc.
Promotion Why? How? With who?
5. Profoss oct. 2007 - 5
AWTwww.awt.be
TelephonyTelephony
•Analog or digital?
•PSTN or converging ?
8. Profoss oct. 2007 - 8
AWTwww.awt.be
From analog to digitalFrom analog to digital
•Sound propagates, artificially, thought an electric signal
after capture4
, sound is transmitted 5
on the line linking the people and is
reproduced on the loudspeaker
disadvantage: analog signal’s quality degrade with the distance and is
disturbed by the noise on the line.
•Electronic and ICT:
Analog moved toward digital
o Digital Signal Processor (DSP) takes with constant interval (sampling) the value of
the analog signal and associate a binary number (0/1)
– 44000 Hz CD quality
– 22000 Hz radio quality
– 8000 Hz PSTN quality
The audio channel is represented by the sequence of these
numbers
o To reduce the throughput (size), the sequence is converted in a compressed format
(CODEC)
– G.711: flow of 64 Kbit/s,
– G.729: flow of 8 Kbit/s.
– CODEC is a compromised between quality, CPU power, bandwidth, time to
transfer (delays), loss tolerance
Integrated Services Digital Network (ISDN) brings digital to the
subscriber
o Basic Access: 2 lines of 64 Kbit/s; Primary Rate Access: 30 BA therefore 2Mbit/s
4 Frequency 0-4 khz
5 Analog: frequency modulation
9. Profoss oct. 2007 - 9
AWTwww.awt.be
Network convergence and adoption of IPNetwork convergence and adoption of IP
•Traditionally, multiple communication networks coexist
STN for telephony
o circuit switched
o associates physically line segments to link end to end the people
Computer network for data
o Packet switched (sets of small data information
thought ‘water bucket chain’ like)
Coax network for TV
Mobile/GSM network for wireless telephony
•Unified network enable to support both voice on a computer network
Voice is an application
o Data are digital
o Communication rules are well known
Relate concept: Voice on Packet (VoP)
o Voice over IP (VoIP)
o Voice over ATM (VoATM) aka VoDSL
o Voice on Frame Relay (VoFR)
Other concept: Voice on Coax (DOCSIS/PacketCable)
Gateways are available to bind (in/out) with the PSTN/mobile networks
10. Profoss oct. 2007 - 10
AWTwww.awt.be
Success factorsSuccess factors
•Migrating to voice over packet ?
•Removing the PBX for IP telephony ?
•When to replace the PBX ?
11. Profoss oct. 2007 - 11
AWTwww.awt.be
Why voice over packet ?Why voice over packet ?
•Initially, VoP was a operator only technology
replacing permanent expensive PSTN TRUNKs
using dynamic less expensive technology through IP
•Nowadays, VoP is available to anybody
thanks to broadband Internet
interest for ICT is large
•Through VoP, « consumer » also benefit of a « substantial reduction
of its communication costs» but this is not the only profit!
•Many additional valuable services are available:
video, chat, content sharing (ex document, photo), application
sharing, instant messaging with employees but also partners,
customers suppliers
unified messaging (voicemail, Email, fax, SMS, MMS, etc. into a single
universal box),
services customization (ring tones per caller, etc.)
mobility (as for GSM) trough wireless (3G, WiFi or WiMAX)
application consolidation
12. Profoss oct. 2007 - 12
AWTwww.awt.be
Why voice over packet ?Why voice over packet ?
•Cost reduction
VoIP rate are ridiculous vs traditional call rates
long distance call increase the possible profit
many extra benefits
o Free call between subsidiaries or with partner & supplier
o Attractive rates thru the usage of an IP telephony operator (ITSP)
•Availability and mobility
PC and phone share the office wires
phone line move seamlessly with the user
•New services and open standard
freedom is recovered: not anymore « prisoner » of a single
hardware/software supplier.
increased inter-working: even is the software vendor is different
•Improved sound quality and clearness
PSTN ‘cut the sound’ to be transmitted on the line
VoIP permit the use better CODEC (ex G722 wideband)
•Simple and easily accessible management
no need anymore to modify the patch panel
giving a user a ‘line’ is easy as providing an email address
most of the time done with a web browser (accessible to boss, secretary)
autonomy increased with respect to the consultants specialists.
13. Profoss oct. 2007 - 13
AWTwww.awt.be
Which is the right moment to give up withWhich is the right moment to give up with
traditional PABX?traditional PABX?
•PABX‘s live is around 7 years
if +, many companies will not put it yet into the dustbin
•Many PABX have been bought in 2000 (cfr bug). They arrived at the end
of their lives/contracts
•For the company
the hardware/software is closed for the accountancy
one should not anymore be bound by a maintenance contract
•Your moment has come if you may answer yes to one of these
is the PABX registered in renewal plan of the company?
is your company located in different buildings ?
are your searching for a centralized billing solution for your telecommunication costs ?
are you introducing tele/remote-working ? Better to have a unique number following
the employee
do you search to improve competitiveness ? Better communication tools may help!
you plan to migrate to an IP ITSP ?
14. Profoss oct. 2007 - 14
AWTwww.awt.be
What is IP telephony ?What is IP telephony ?
•Distinction between VoIP, trunking, ToIP, Internet Telephony, …
•The « bridges » between IP & PSTN worlds
15. Profoss oct. 2007 - 15
AWTwww.awt.be
VoIP is not theVoIP is not the
perfect synonym of ToIPperfect synonym of ToIP
•trunking
telecom technique to aggregate lines
simultaneous transport of many calls
physical dedicated line between 2 phones switches
expensive
•Voice Over IP
substitution of a trunk by a IP connection through a data network
o private (eg: from operator, (inter)national WAN of the company)
o public (eg: Internet)
substitution of the line dedicated to telephony by a shared channel
between data & voice.
transport is done from hop to hop
•Benefits
synergy of the infrastructures
reduction
o exploitation cost
o number of required technicians
« centering » technical skills
o telecom roles become a part of ICT & network administration
16. Profoss oct. 2007 - 16
AWTwww.awt.be
VoIP is not theVoIP is not the
perfect synonym of ToIPperfect synonym of ToIP
•Telephony over IP
« ultimate » stage in the migration to ‘all IP’
transport with packet is done end to end
Important strep towards the notion of services convergence
replace
o traditional telephone by a « IP phone »
o the hardware PBX by a Server Software9
or an IPpbx (running on an
OS: Windows, Linux, Unix,…)
•Characteristics of ToIP. one replace
phone jack (RJ11) with a network plug (RJ45)
analog/digital interface by an interface using IP protocol
traditional signaling (SS7, ISDN) by voice over IP (H.323, SIP, IAX)
(vendor specific) phone headset
o a new phone terminal
o a software (softphone) usable on a PC, PDA, Smartphone,…
9 also named SoftSwitch
17. Profoss oct. 2007 - 17
AWTwww.awt.be
ToIP ‘s deployment scalesToIP ‘s deployment scales
•Qualified definition
Closed Zone (Intranet): private IP telephony server
Half-Public Zone (Extranet): private IP telephony server open to partners,
suppliers (eg: through VPN)
Limited Public Zone (Internet): opening of the IP telephony server to the
world without PSTN or mobile IP ITSP
Public Zone (Internet): opening of the IP telephony server to the world
with PSTN and/or mobile IP ITSP
•ToIP goes further than Voice over IP
Video transmission
Fax transmission (T.38)
Computer-Telephony-Integration
19. Profoss oct. 2007 - 19
AWTwww.awt.be
IP Phone variationsIP Phone variations
•New generation
The association of
o a software which supports a particular ToIP protocol
o a user interface composed of a mike, a (alpha-)numeric keypad and
usually a LCD display
3 categories
o HARDware telePHONE (hardphone): electronic device with a ToIP
software and an integrated User Audio Interface with design similar to
regular phone10
o Softphone: an application running on a computer where the User
Interface is the computer audio accessories
o Analogue Telephone Adapter (ATA): electronic device with a ToIP
software without an integrated User Audio Interface but offering a plug
for your old regular phone
10 using the same plug as PC (RJ45 )
for data and current (PoE)
20. Profoss oct. 2007 - 20
AWTwww.awt.be
Telephony applicationTelephony application
•Operation of this application
•Securing this application
•Potential of the application:
Computer Telephony Integration (CTI)
21. Profoss oct. 2007 - 21
AWTwww.awt.be
Operation principlesOperation principles
• IP communication establishment is realized in two steps:
1. reciprocal presentation of the phone application
2. setting up the media(s) stream channel(s)
• Numerous techniques to achieve the first step
proprietary :
o many solutions appeared in the 90’s with the Internet
o protocol not recognized as worldwide standard
o often lack of interoperability: user is confined is his community
o protocol may be publicly available (eg IAX, Jingle) or totally private (eg Skype, MSN)
standardized:
o the software is compliant with a well known and defined protocol (eg H.323, SIP)
o interoperability: user in one community may contact whoever in other compliant
communities
o international organization bodies:
– ITU-T: telecom oriented, specification must be bought
– IETF: Internet philosophy, specification is free
o broader availability and choice of products/softwares
• Broader dimension than simply voice! Additional media:
video,
white board,
written text (chat/im)
whatever useful application: presentation, co-browsing
A simple voice call become an collaboration session
with a rich media experience
22. Profoss oct. 2007 - 22
AWTwww.awt.be
First step:First step:
Network parameter exchangeNetwork parameter exchange
•At the user level,
Mutual exchange of the “digital identity”
o traditional phone number (E.164),
o virtual identity: nickname, loginname
o real firstname or name,
o email address,
All of these may be taken from a directory (LDAP, MS AD)
•At the application level
Mutual exchange11
of endpoints network information
o what is the IP address of your communication software?
o what are the TCP/UDP ports your communication software uses for
audio, video, text messages, etc ?
•Technical term is «call signaling »
•Many signaling protocol have been created
SIP: Session Initiation Protocol,
IAX, Inter Asterisk eXchange
H.323: Packet-based multimedia
communications architecture,
Net2Phone,
Skype,
MSN,
Jingle,
Megaco / H.248: Media Gateway Control protocol,
SCCP: Cisco Skinny Client Control Protocol,
etc 11 If peer is on PSTN/mobile, parameter (IP & ports) are
those from the gateway
23. Profoss oct. 2007 - 23
AWTwww.awt.be
Internet sharing (PAT/NAT) is a problemInternet sharing (PAT/NAT) is a problem
•Network Address Translation (NAT):
public IP size < number of stations on the LAN
a LAN station is temporary FULLY publicly available (like dialup in the 90’s)
•Network Address Port Translation (PAT)
all LAN’s stations share the SAME public IP address
a LAN station is temporary publicly available with limitation
Some ports may be already allocated to another LAN station!
•Problem occurs if the following private IP address are used
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
169.254.0.0/16
Negotiated network parameters are only valid on the private LAN
Impossible to communicate with the outside (partner, supplier, low cost ITSP)
•Solutions
Using public IP address on all phone: get more public address (IPv6)
Forcing old fashioned methodology (all calls through a single box such an IPpbx)
Using ‘technical tricks’
o Using dynamic hostname resolution (DynDNS,…)
o Dedicated technologies:
– IETF STUN: Simple Traversal of UDP through NATs
– IETF (work in progress) ICE: Interactive Connectivity Establishment1
– UPnP: Universal Plug and Play
– IETF MIDCOM : Middlebox Communication, Firewall Control Protocol
24. Profoss oct. 2007 - 24
AWTwww.awt.be
Second step:Second step:
The communication itselfThe communication itself
•After technical parameters exchange, media transport application(s)
takes the relay
•Medias may have different requirement
real time (audio, video, presentation sharing)
asynchronous (IM, chat)
•Transport technology missions are
to transform the media using a CODEC to create the IP packets to send
to realize the transmission of these IP packets to the destination
to reorder these IP packets after reception
to detect and resolve packet loss
etc
•Real time transport technologies:
Real-Time Protocol (RTP): data, audio, video
Real-Time Control Protocol (RTCP): ensuring QoS for RTP
Compressed Real Time Protocol (cRTP) or Enhanced Compressed Real
Time Protocol (ecRTP): RTP alternative for slow network (GPRS/UMTS)
Secure Real-Time Protocol (sRTP) & Secure Real-Time Control Protocol
(sRTCP): RTP/RTCP with confidentiality
25. Profoss oct. 2007 - 25
AWTwww.awt.be
Security challenges in IP telephonySecurity challenges in IP telephony
•Identification/Authentication. Avoiding
tool frauds
usurpation of the identity of the participants
that the communication be
o torn down by someone else
o altered by someone else (headers, session description, etc)
o deviated to someone else
•Confidentiality. Avoiding that by someone non authorized
collect some data (subjet/time/duration of the call, participants)
capture and listen to the communication streams (wiretapping)
•Quality of Service
avoiding conversation’s or video’s quality degrades
avoiding that the communication does finish suddenly
ensuring that the communication can be established
26. Profoss oct. 2007 - 26
AWTwww.awt.be
Securing IP telephonySecuring IP telephony
•V/ToIP has become an application!
vulnerable to the same problems as the other network’ softwares
•Possible attack’ scenarios
attacks against the operating system (OS) underlying the voice or multi-
media software (IPphone, ATA, gateway, …)
attacks against the weaknesses within the configurations
o Default password
attacks against protocol vulnerabilities
attacks against software’s bugs
attacks against the networks
o reducing performances (throughput, CPU load, memory overload)
o scrambling of a wiki network
attacks against the servers which host the telephony services
o reducing performances,
o Installation of virus, spy
Non solicited calls: SPam over Internet Telephony (SPIT)
•Important roles to take care (emergency call, geographic localization, …)
27. Profoss oct. 2007 - 27
AWTwww.awt.be
What are the protections ?What are the protections ?
•Many techniques are available
OS security enforcement
network security enforcement
quality ensured software development
QoS network technologies
ISO 17999 guidelines
•Some basic advices
using VPN or SSL when data cross over a non trusted network (ex Internet)
defining distinct VLANs to separate data and voice traffic within the same
switch
protecting the media with encryption such SecureRTP
protecting the network with firewall, IDS, IDP
configuring and managing correctly the IP Phones
defining a call policy « dial plan » (usage rules)
keeping an eyes on security news updates and patching software when
necessary
protecting again power outage with UPS on the switch to enssure « Power
over Ethernet »
28. Profoss oct. 2007 - 28
AWTwww.awt.be
Computer Telephony Integration (CTI)Computer Telephony Integration (CTI)
•Traditional telephony
is not only making/receiving calls
supplementary services are associated
o call transfer to another phone
o message waiting indication
o second call notification & pickup
o calling line identification number (CLIP)
o presentation of the caller name
o audio answering machine & voice mail
•A « good » ToIP should
offer at least the same features
go further into the integration with other application of the enterprise
•Next Generation Services
universal access to the user or the enterprise address book
gather and display context specific information (customer account)
video answering machine & video mail,
redirection to other communication channels (email, web site)
LAN or world (roaming) wide mobility of the phone
centralize maintenance of a distributed system
gateway broker: service to select the most appropriate exit point
collaboration work: application sharing, web-conferencing, instant file
exchange
29. Profoss oct. 2007 - 29
AWTwww.awt.be
IP telephony has many flavorsIP telephony has many flavors
•Proprietary norm or well established standard?
•Enterprises' deployment models?
Hosted, In-House, Centrex,…
•IP pbx or
the « metamorphosis » of an electronic component into a software…
•Technology model for today’s voice & tomorrow’s multimedia
30. Profoss oct. 2007 - 30
AWTwww.awt.be
Proprietary norm orProprietary norm or
well established standard?well established standard?
•Proprietary norm
“ Is a way of realizing a service usually restrictive, exclusive, subjected to
constraints and for which the ‘receipt’ is often a trade secret. ”
Usage of such norm often causes the birth of closed communities
•A standard or open norm
does not mean that source code of the software should be published to third
party,
mean that the software respects the operations defined by the specification
written by a well established organism/consortium
•Therefore, a point to clarify
« open standard must not be confused with the concept of open source»
•Open norm’s assets: « the federation of services »
by using such norm, different communities may communicate with each other
similar to the forwarding of a mail from me@XXX.be to you@YYY.be
31. Profoss oct. 2007 - 31
AWTwww.awt.be
Deployment modelsDeployment models
«The deployment scenarios of a Voice (presence and instant messaging)
over IP solution may be compared to the installation of an Internet
messaging system (email)»
•Alternative choices:
Keep ownership of the solution
installing the V/ToIP server in the enterprise network (LAN/DMZ)
Multi sites enterprise may decide to place a server
o into each geographical establishment of the company
o only in the headquarter of the company
housing of the de V/ToIP server in a datacenter
Access to associated PSTN bridging services
o thru gateway located in strategic establishment of the company
o thru IP bridging services offered by an telecom operator or an ITSP
Renting of the solution
subscribing to the services of an telecom operator or an ITSP: Centrex mode
o pay per use/seat
o characteristics
– hosting of the V/ToIP server in a datacenter
– access to the provider PSTN bridging services
32. Profoss oct. 2007 - 32
AWTwww.awt.be
V/ToIP (Multimedia) architecture modelsV/ToIP (Multimedia) architecture models
•Centralized:
« ’old’ telecom operator philosophy »
characteristics
o resource reservation and call signaling are similar to what is done in the
PSTN
o the intelligence is only within the network
o single centralized management
o terminals are relatively ‘stupid’
o few features in the users terminal
•Distributed:
« Internet minded philosophy »
characteristics
o intelligence is shared between network signaling elements and the end
user terminal
o signaling intelligence is divided into multiple entities
o terminal are IP phone, PC (softphone), PSTN gateways
o system are more flexible and its easy to add a new service
o task are delegated to the most appropriate network entity (eg: DNS to
locate a service)
o system are more complex
33. Profoss oct. 2007 - 33
AWTwww.awt.be
TechnologiesTechnologies
Telco driven: PBX is kingTelco driven: PBX is king
•Centralized technologies:
Media Gateway Control Protocol (MGCP): std IETF
Media Gateway Control (Megaco H.248): std ITU-T/IETF
•Distributed technologies:
H.323: std ITU
o ‘copy/paste’ in IP of the way RNIS/ISDN operates
– the operation is similar than the PSTN
– adaptation to IP is ‘RAW’ (no real reflexion on how to benefit of
existing IP services…)
o v1=NetMeeting; actual is v5
o signaling is in binary
o components: terminal, gatekeeper, gateway
Skype
o proprietary
o at its root an Internet Telephony tool
o nowadays an ITSP service too
o the Peer 2 Peer (many to many) which make it a distributed system
o the communication between the caller and caller transit thru a large
majority of SKYPE community users
– security issues
– Resources consumption
(CPU, BW) even if no ongoing calls
34. Profoss oct. 2007 - 34
AWTwww.awt.be
IP pbx TechnologyIP pbx Technology
•Traditional PBX is made of
Electronics component and telephony ASICs
A Foreign eXchange Subscriber (FXS) jack for EACH telephone lines
Telecom services
o Functions: ISDN, SS7,QSIG (inter-PBX, userline)
o Interconnection norms EuroISDN, Lucent 5E, National ISDN2, …
o Voice servers (IVR, voicebox)
o Unique features (proprietary ?) to the brand of the PABX!
•An IP PBX is
Still qualified as traditional vs ToIP. Follows the old TELCO philosophy
First evolution: ‘simple’ PABX with an ethernet card to bind to IP. To enable
o a software interface client on PC (preferences, call logs,…), TAPI14
norm
o a integration with ICT
– Listening voice email from PC
– Dialling from a software keypad or an address book but call ends to telephone
o a link (BA/PRA) to an IP telephony provider trunk
Nowadays, a full application to install on a server PC (Small Form Factor)
o A PABX software
o Telecom extension boards (BA/PRA, E1/T1, …)
o Obviously an ethernet card for IP trunks (H.323 initially, SIP and IAX now)
o ToIP lines (H.323 initially, SIP now and some IAX)
o DSP to carry voice from regular phone to IP phone and vice versa
o Hard disk for voice mail storage
•Actors
Majors following the market; IP cards and new software for ‘old’ PBX: Alcatel-Lucent, Avaya,
Siemens, TIPtel, Ericsson,...
Telephony news comers are also strongly present:
o Cisco (CallManager <=5), ….
o Open Source Asterisk and all its ‘customisations’
14 Telephony Application Programming Interface:
fonction CTI sous MS Windows
35. Profoss oct. 2007 - 35
AWTwww.awt.be
How (IP)pbx calls works ?How (IP)pbx calls works ?
The Octopus at work!The Octopus at work!
Line 1
in port 1
Line 2
in port 2
Line 3
in port 3
Line 4
in port 4
IP enable the virtualization of
the physical port!
36. Profoss oct. 2007 - 36
AWTwww.awt.be
Asterisk in a slide…Asterisk in a slide…
•An IPPBX open source software created by Mark Spencer and is now
sponsored by Digium (manufactures analog and digital interface cards work particularly well with
Asterisk, long-term profit motive)
•Asterisk is currently in its 1.4 stable release, and supports a very
impressive range of features:
Full support for analog, digital (T1, E1, PRI) and IP telephone interfaces (SIP, IAX and
H.323 via external library)
Improved FoIP support
Support for VoIP and analog telephone handsets thru boards interface card
Ability to run in generic Linux servers or Mac OS X
Extensive list of built-in call management features (e.g. call transfer, three-way
calling, all of the usual telephony functions of a PBX)
Meet Me dial-in conferencing
Fully configurable extension numbering (dial plan)
Automated call distribution (for customer contact centers)
Music on hold from a local recording or live MP3 or G.711 audio stream
Unlimited extensibility through AGI (Asterisk Gateway Interface): developers may
build custom CGI programs that control the telephone system
Interactive Voice Respond system (IVR)
Voice mail
Act as a glue toward many proprietary protocol (Skype, Skynny, MSN , etc)
Full LGPL source code
•Need a synergy with a SIP proxy solution (SER,OpenSER, SIPFoundry ?)
in open source in order to become a full fledge next gen Open Source
Communication solution. NB: Some OS IPtel players have understood eg: carrierclass.net
37. Profoss oct. 2007 - 37
AWTwww.awt.be
Asterisk market viewAsterisk market view
•Some news from September 2007 Voice on the Net (VON) Italy
Workshop “Open Source VoIP, sustainability of OS projects in the
business sector” Thanks to Diego Gosmar from Wildix
Co–author of the Book "Asterisk and Surroundings"
•What « people » thinks
Niche market today but increasing fast
Too complex for end user but very flexible for the professionals
Not ready for big enterprise unless you have some good professionals
Expensive “after all”, if you start from scratch
Lack of support from a single vendor
Part of open communication blocks
•Market true bottleneck
Too much fragmented offer
To many companies selling their “own solution’
Too many hardware platform
The PBX core is stable, what about the software on top ?
•Where asterisk should go ?
Standardize User Interface (more that 30 <> up to now), CTI, API for
application integration
Provide more video
Include a real SIP (statefull) proxy
38. Profoss oct. 2007 - 38
AWTwww.awt.be
TechnologiesTechnologies
Internet driven: network is kingInternet driven: network is king
•Distributed technologies
Session Initiation Protocol :
std IETF
his simplicity pushes it as the alternative to H.323
de facto ‘s standard for multimedia communications NgN networks
a cousin of HTTP (web)
o Signalling messages de signalisation are text based
o The result of a real reflexion ‘from scratch’ on how to do VoIP in an
worlwide IP network
o reuses many existing and standardized protocols which are well known
and established (DNS, SMTP, …)
o Inherit of all R&D efforts which have been made on IP protocols design
strongest strength is mobility, nomadicity and forking (one ID with
many locations!)
39. Profoss oct. 2007 - 39
AWTwww.awt.be
TechnologiesTechnologies
Internet driven: network is kingInternet driven: network is king
•SIP Component:
IP phone is named a User Agent (UA)
distribution of the functionalities Registrar, Proxy and Redirect servers
‘Location Service’ (LS) to memorise the User-Location(s) records
•Servers roles
Registrar takes care of the user-location associations and potential telephony services preferences
o Bind a user’s phone endpoint with an IP network location (address+port)
LS is similar to a White Pages service
Proxy takes care of routing the messages to the right network destination(s)
•User addressing is at your convenience
User-Resource association is a Universal Ressource Identified (URI)
« protocol:username@domain »
o sip:carmelo@awt.be SIP account
o tel:+3281778080 SIP account alias (may or may Not be my desktop office phone)
o mailto:carmelo@awt.be Mail account
o http://www.awt.be/~carmelo Employee web space
A URI identifies a person, a resource or a group BUT not a dedicated hardware phone!
A technologie to map a URI to a phone number E.164 and vice versa:
tElephone NUmber Mapping (ENUM)
•Actors
majors understood the evolution; brand new architecture: Alcatel-Lucent, Avaya, Siemens, Nortel,...
news comers are also strongly present:
o Cisco (Communication Manager 6), Microsoft, BroadSoft, Indigo Software, Radvision, Adobe, ….
o Open Source SipExpressRouter, OpenSER, SipFoundry (Pingtel opening its code), …
40. Profoss oct. 2007 - 40
AWTwww.awt.be
How Next Gen calls works ?How Next Gen calls works ?
The Ant at work!The Ant at work!
41. Profoss oct. 2007 - 41
AWTwww.awt.be
IPtel economy in the RW…IPtel economy in the RW…
•Mainly SIP, then IAX and some MGCP/MEGACO veterans!
•Least cost routing (Hidden DID)
•Premium cost routing (DID showed & availability of some Belgian E.164 : +32)
•DID free or with fee
•Pre-paid or post-paid models
•With or without voicemail
•All in one service on a ‘price per seat’ AXIS (+ calls cost)
•With or without SLA
QoS if controlled network (ex Win, Bilan, Telenet, Verizon, … )
o Network in between the customer and the PSTN gateway
o Network in between the customer premises
QoS is still a challenge for ITSP
o Need to negotiate a contract with Internet service providers (DiffServ, RSVP,
MPLS, …) to better server customers
•Professional and residential services offers
•Many IP Phone. Usual vendors (Alcatel, Siemens, Cisco, D-Link) & mass
import (Grandstream, Snom, Funkwerk, Swissvoice, Tornado, Lancom, …)
•Many Softphone (free, with fee, open source or not :Gizmo, Ekiga, Windows
Messenger, X-Pro, Eyebeam, Bria, etc)
Fax over IP (FAX T.38/T.30) support is still very poor. (often transport thru the voice channel
but with related issues…)
42. Profoss oct. 2007 - 42
AWTwww.awt.be
IPtel actors in the RW…IPtel actors in the RW…
•Traditional players (Cisco, Alcatel, Nortel, Avaya, …)
•Challengers
Open Source standard (H.323/SIP) ou non (IAX)
o Tree categories:
– knowledge in open source but no real knowledge of the « voice application »
– knowledge in open source and REAL knowledge of the « voice application »
– knowledge in open source and REAL knowledge of the « voice application » AND open
source certifications (Redhat, Suse, Asterisk, etc)
o Many in Asterisk
– Escaux (Wavre), Eyepea (Sainte), Novacom (Mons), Alterys (Verviers), PacketNet
(Schoten), WeePee (Greembergen), SYNsip (Hamme-Mille), Asixtel (Wauthier Braine ), …
o Two categories of Asterisk player
– Base Asterisk with or without third party GUI
– Asterisk with self developed ‘custom extension’ (GUI or other)
o Many less with SER, OpenSER, Sipfoundry/sipX, trixbox, CallWeaver
(OpenPBX.org), FreeSWITCH , Yate, Bayonne, etc
– Novacom (Mons), SYNsip (Hamme-Mille)
Close Source
o Radvision (H.323/SIP/SIMPLE)
o Quintum/Worldcall (H.323/SIP)
o Indigo Software (SIP/SIMPLE)
•Visionaries actors
Computer/Web Telephony Integration
Presence management & collaboration tools
•Many product resellers (Softphone, IP Phone, gateway, ATA)
43. Profoss oct. 2007 - 43
AWTwww.awt.be
ConclusionConclusion
Key advices from the AWT in the domain of
IP Telephony
44. Profoss oct. 2007 - 44
AWTwww.awt.be
Advices from the AWTAdvices from the AWT
•ToIP should not be considered as « the » new gadget to
possess.
It’s an evolution which requires a serious study. Ideal moment to think about a migration to
the new voice technology is to benefit of a positive situation such as the necessity to replace
the PBX
•ToIP is closely linked to the reduction of the voice
communication bill. However this is not necessary the most
important point to consider.
Improvement of the company organisation and of the quality of the labour are very important
factors. With this in mind, ToIP is in perfect synergy with the concept of professional mobility
according to which the Office and it’s facilities do follow the employee in his travel.
•The usage of a worldwide well established standard is the
warranty of a long lasting migration’s investment .
Similarly, the introduction of a brand new telephony system should also consider the close
integration and collaboration with the computing applications or services of the company.
•Quality of Service and computer security of the system and of
the communication MUST be central to the choices of a new ToIP
infrastucture.
An enterprise could not accept to reduce the quality and stability of its call or that that
confidential information may be intercepted by unauthorised entities
•Resources on www.AWT.be
White papers:
o « La téléphonie sur IP »
o « Les VLAN Ethernet»
News Focus « Quel est l'état du marché de la téléphonie IP? »
Files:
o «Business mobile »
o « Guide sécurité informatique »