VoIP Study and ImplementationVoIP Ecosystem and Strategy

Version 1.0 – Author : Marc PYBOURDIN / Julien BERTONLast Update : 15/05/2012

Course objectives

• The VoIP ecosystem : Understand the VoIP concepts and the different actors on the market

• Architecture strategy : Understand the differences regarding centralized or distributed architectures.

By completing this course, you will see:

VoIP ecosystem and architecture strategy

OVERVIEWVoIP Ecosystem and Strategy

Description

• VoIP (Voice over IP)• A set of elements that provide voice

transmission through an IP network.

• ToIP (Telephony over IP)• Wide range of telephony

services such as• Voicemail• Conference rooms• IVR• …

Overview

Why VoIP ?

• Mobility

• Cost

• Speed and reliability of IP networks

Overview

Architecture exampleOverview

- Traditional telephony can be linked to VoIP (by using FXO or FXS adapters)

Some vocabulary

• For VoIP :– IPBX : IP Private branch exchange

• Asterisk, Cisco Call Manager, Alcatel …

• To link traditional telephony with VoIP : – FXO : Foreign eXchange Office : Phone line to PSTN

– Think about the RJ11 plug on your Internet box(the one that input your analog copper line to your box)

– FXS : Foreign eXchange Station : Telephone interface for end-user devices– Usually provide power and dialtone

Terms

Overview

VoIP ProtocolsOverview

Acronym Name

SIP Session Initiation Protocol

MGCP Media Gateway Control Protocol

IAX Inter-Asterisk eXchange

SCCP Skinny Client Control Protocol

RTP Real-Time Protocol

RTCP Real-Time Control Protocol

Any questions?

THE SIP PROTOCOLVoIP Ecosystem And Strategy

About the protocol

• Signaling protocol• Not used for voice transport • Made in 1996 – RFC 3261• Client/Server Mode but can be used

in P2P mode

The SIP Protocol

The SIP protocol

• Standard port : 5060 UDP (can work with TCP)• Return codes are similar to HTTP protocol

– 1xx : Information (180 : Ringing, 100 : Trying)– 2xx : Success (200 : OK, 202 : accepted)– 3xx : Redirection– 4xx : Client error (404 : not found, 401 :

Unauthorized)– 5xx : Server error– 6xx : General failure

• Usage of URL such as : sip:1568@sip-server.org

The SIP Protocol

SIP Components

– A User Agent (UA)• The client part

– SIP server–Handles SIP signaling and channel setup

– A SIP trunk (optional)–Usually connects to a SIP provider to

receive/placecalls on PSTN

The SIP Protocol

Establishing a communicationThe SIP Protocol

Description

• Replace/extend traditional telephony– Local communications– International communications

• Merge networks together – Convergence

=> Need of QoS!

• Provide new services– Services provided by LAN infrastructure

VoIP objectives

The SIP Protocol

Codecs

• Protocols-free• Algorythm : COmpress / DECompress• Compress Human voice in digital packets• Implemented

– On softwares– On network devices

• Most used– G.711 µ-Law

• 64kbps per channel

– G.711 a-Law• 64 kbps per channel

– G.729• 8 kbps per channel• Requires licence in some cases

The SIP Protocol

Any questions?

VOIP ARCHITECTURESVoIP Ecosystem And Strategy

DescriptionDeported IPBX

VoIP architecture

VPN tunnel (optional)

Site A Site B

IPBX

- Site A phones are linked to the Site B IPBX

- Site B down = No telephony for site A

DescriptionLocal IPBX

VoIP architecture

VPN tunnel (optional)

Site A Site B

IPBX

- Sites A & B have a dedicated IPBX

- Sites A & B are independents

IPBX

VoIP actors

- SIP trunk providers- OVH

- Keyyo

- Ippi

- ICTelecom

- Hardware manufacturers- Cisco/Linksys

- Cirpack

- Thomson

- Aastra

- Siemens

The SIP Protocol

Desktop SIP clientsVoIP architecture

- Windows

- X-Lite

- Mac

- Blink

- X-Lite

- Telephone

- Linux

- Ekiga

- Twinkle

Mobile SIP clientsVoIP architecture

- iPhone

- Acrobits Softphone

- Android

- Sipdroid

- CSipSimple

- Telephone

- Windows Phone

- MobileVoIP

- Skype

Any questions?