Cisco IP Telephony

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Voice over Internet Protocol (VoIP) has been growing steadily in popularity over the past

years. Instant messenger clients with voice chat features have given way to P2P (peer-to-

peer) VoIP clients like Skype. We take a closer look at VoIP (Voice over Internet Protocol)

technology, and the challenges and innovations associated with it.

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VoIP, or Voice over Internet

Protocol, is the technology used totransmit voice over the Internet. Also

known as ‘Internet telephony’, itinvolves breaking up analogue voice

data into digital packets, and thentransmitting these packets using the

Peering Under The HoodOf VoIP Technology

if you have been on the Internet

long enough, there is a goodchance that you have spoken

to someone over the Internet,either using a traditional chat

client (like Yahoo!), or P2P softwarelike Skype.

P.A. MonteiroThe author is a freelance writer living in Bangalore.

He advocates the user’s point of view on his blog athttp://allaboutusers.wordpress.com





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and data provides opportunities for

companies to innovate solutions. Forexample, one company allows you to

receive your voice messages as MP3files that are sent as attachments to your

e-mail address. We also look at some

other innovations in the VoIP space.Click to call: You may havealready seen websites that allow you to

click on a button and chat with ‘live’support personnel. Similarly, a VoIP

technology called click-to-call allowsyou to call people by clicking a banner

or a button on a website. Click-to-callis already being offered by companies

like Ifbyphone, Yellow Pages andEsqube Communication Solutions.

VQube, India’s own P2P VoIP tool: Esqube Communication

Solutions Pvt Ltd, a Bangalore-basedcompany, recently released a product

called VQube, which the company calls, “…a peer to peer Voice over IP

interactive communication tool that

offers voice, video, text chat and voicemail.”

On the subject of how the Esqubeteam designed the product to address

technical challenges in the Indianmarket, Dr K V S Hari, CEO,

Esqube Communication Solutions

Pvt Ltd, says, “e main technicalchallenges we face in India are inthe areas of hardware limitations,

network constraints, and bandwidthlimitations.”

He reveals, “VQube uses alightweight voice codec that needs

lower CPU time (compared to othercodecs), thus keeping the CPU and

memory requirements to a minimum.is means that VQube works

satisfactorily on older machines and on

older versions of operating systems, as well as on set-top boxes installed withLinux and Windows mobile phones.”

“Since bandwidth in India is stillat a premium, VQube uses a secure,

lightweight protocol for transportingvoice packets, which reduces the

overhead and contributes to bandwidth

reduction. Bandwidth usage (for voice

and video calls) was also minimisedusing techniques like dynamic voice-

codec switching, video frame rateselection, and so on,” he says.

About the network-related

challenges, Dr Hari says, “In many networks, the desktop is in a privateIP behind a NAT (network address

translation), with the same Internetconnection shared by all users.

Sometimes the Internet connection isin a tight firewall (only standard ports

are open to the outside world), and canonly be accessed via a proxy.”

“VQube’s network discovery protocol detects the type of network,

the type of proxy, and the portsthat are open for voice packets to go

through, and automatically routesthe packet without reconfiguring the

network. Also, in most conditions,packets travel P2P, thus minimising the

delay,” he adds.

IP video: If you can transmit voice

and data using IP, then the next step would be to add video. Companies are

already working on products like IPvideo phones, and video conferencing

systems.

About IP video phones, Kumarsays, “Ittiam’s technology has beenlicensed and taken to market by

multiple vendors, and is currently under a trial run by an Asian major.

Although the IP video phone is stillan emerging market, there is a clear

sign of increasing interest and intent of

adoption by major OEMs around the

world.e future of video telephony is

bright, and it will come into our livesin multiple forms, like video phones on

desktops, video phones on IPSTBs (IP

Set Top Boxes), video communicationembedded in ATMs, etc.”

Private networks : Since the

Internet is a public network, there areinherent pitfalls (e.g., security, voice

vs data traffi c priority) associated with transmitting voice calls over the

Internet. Some VoIP service providersuse dedicated private networks that

enable secure and faster transmissionof voice calls. Using private networks

also allows service providers to tweak parameters for better performance (for

example, prioritise voice traffi c overdata traffi c).

One example of a private network is the Multi-protocol Label Switching

(MPLS) network that is used by VoIP

service providers.

Challenges facing VoIP

Since VoIP is a relatively new technology, challenges are to be

expected as the technology matures.

We look at some of the challenges inthis domain.

Security: e one challenge thatseems to come up in every discussion of

VoIP, is security. Addressing this point,Minhaj Zia, business development

manager, Cisco India & SAARC says,“One of the most common threats is a

denial of service (DoS) attack, whichshuts down applications or servers.

ese attacks are often made againstrouters or Web servers, but they can

also be used to target call-processingservers in IP telephony networks.

“Call tampering, which involvestampering with a phone call in

progress, is also emerging as a threat.For example, the attacker can spoil

the quality of the call by injectingnoise packets in the communication

The convergenceof voice anddata providesopportunitiesfor companies

to innovatesolutions.



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t e c h f o c u s stream. Or the attacker could withhold

the delivery of packets, so that thecommunication becomes spotty and

the participants encounter long periodsof silence during a call.”

Shawn Conroy, vice president -

voice networking, AT&T Inc says, “A secure VoIP deployment must includea combination of existing IP security

mechanisms and VoIP-specific security mechanisms. Ultimately, the security

of a customer’s VoIP services dependsnot only on the security measures that

the vendor deploys in its network andservices, but also on the security that

the enterprise customer implements atits own locations.”

He adds, “Many of the security measures taken by vendors such as

AT&T, to secure VoIP, must also bedeployed by an enterprise on its own

devices to be fully effective. Security at the customer’s premises is a critical

component of end-to-end VoIP

security.”Prof Schulzrinne expresses his views

on security saying, “In my opinion,

most of the problems can be traced

back to implementations —eithersloppy implementations that fall prey

to buffer overflow and call-state attacks,or lazy implementers who do not

implement well-documented security

techniques, such as TLS (TransportLayer Security) for signalling. eone major protocol deficiency is

probably the lack of a standardised key agreement protocol for media security.”

Spam calls : Because VoIP callsare sometimes routed through public

networks (like the Internet), there is apossibility of spam. Prof Schulzrinne

says, “I have not heard about any real incidents of SIP-based spam,

presumably because most SIP-basedsystems are still closed. SIP Identity is

a precondition for many of the otherspam-fighting techniques, such as white

and blacklists, or more sophisticatedversions, such as whitelists based on

social networks.”

He adds, “Several other kindsof techniques have been proposed,

such as detecting spam calls based onfrequency or duration, or using the fact

that callers start speaking immediately rather than waiting for a “Hello”

greeting. Most of the techniques in the

latter group have the disadvantage that

they are likely to suffer from high false-positive rates, i.e., non-spam calls that

are falsely labelled as spam. (For example,automated phone alerts or airline

departure delay notifications are likely to

be labelled spam.)”Codecs: About the challenges inimplementing codecs for VoIP-related

technologies, Kumar says, “For VoIP-related technologies, several aspects

of codecs and components need to beexamined. e most important ones are

implementation optimisation, system-friendly implementation and testing.

Since VoIP is a low-delay real-time system, the algorithms should be

optimally implemented so that they introduce the least amount of processing

delay. In addition to implementationoptimisation, the components must be

usable, and implemented so that thesystem has maximum flexibility in using

them.”

He adds, “A core component likea codec must then be put through

stringent and exhaustive tests. Examplesof such tests are, a speech decoder’s

behaviour if the data is corrupted, or anecho canceller’s performance when put

through a non-linear path.”

Issues specific to India : On thechallenges faced by VoIP in India,Zia opines, “In India, the biggest

challenges were the regulatory restrictionsimposed by the Indian government

and interoperability issues that resultedfrom a lack of standardisation. Until

recently, a single infrastructure for publicswitched telephone network (PSTN)

and Closed User Group (CUG) was notallowed in India. However, the TRAI’s

(Telecom Regulatory Authority of

India) notification on the approval for“logical partitioning” of PSTN and CUGnetworks means that companies can

reduce their investment expenses. is isbecause they would not have to manage

the expense of two separate (PSTN andCUG) networks.”

About the non-technical challenges

Experts believe that a secure VoIP deployment

must include a combination of existing IP security

mechanisms and VoIP-specific security mechanisms

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faced in India, Rajasekharan N K,

executive vice-president—BusinessDevelopment, Esqube says, “One

challenge is the reluctance of IndianISPs to adopt Esqube’s home-

grown technology in spite of the

threat of revenue loss from (foreign)service providers like Skype. eother challenge is the government’s

regulatory framework related to therestriction of VoIP to PSTN gateway

termination within India.”

The future of VoIP We asked people from the industry

about the future of VoIP in India.

Shawn Conroy observes: “BusinessVoIP is picking up speed as more

companies are turning to VoIP toimprove functionality and increase

cost effi ciencies. ere is a sizablegrowth market, particularly in India,

as corporations are leveraging VoIPsolutions and services.”

Rajasekharan shares a similar

opinion: “e future of VoIP in Indialooks positive. Products like VQube,

which support secure multimediacommunication, in addition to

VoIP, will find traction due to multi-

location enterprises that are lookingat improving effi ciency and reducingcost. Students travelling abroad

for higher education will drive theresidential VoIP markets, since families

and friends will want to keep in

touch at low costs. In addition, socialnetworking sites like marriage portals

will find a need to adopt VoIP to

attract more memberships.”

K L Narayanan, head—BusinessUnit, Convergence, Avaya

GlobalConnect adds, “Clearly, thefuture of communications is VoIP.

Businesses and consumers are already

taking advantage of the cost savingsand new features of making calls over aconverged voice-data network.

“e logical next step is to takethose advantages to the wireless world.

e potential impact of wireless VoIPon the communications market is

enormous.“Wireless VoIP offers potential

savings by allowing companies tochange the way they manage their

phone systems. On the lines of Web2.0, there could be something like VoIP

2.0, which will facilitate more flexibility,customisation and powerful features. It

will be the next phase of VoIP.”e future is clearly bright for

VoIP.

“Clearly,the future of

communicationsis VoIP.”

K.L. Narayanan, head—Business Unit, Convergence,Avaya GlobalConnect

PowerPoint Gets Unpopular in the US Military?

Believe IT or NotNimish [email protected]

m icrosoft’s PowerPoint

might be themost powerful

presentation toolin the world,

but it seems to have run afoul of theUS military. In his best-selling work

on the ongoing war in Iraq, ‘Fiasco’, journalist omas E Ricks points out

that many members of the US military

were extremely irritated with someoffi cers’ penchant for using PowerPoint

presentations to get their point across.Ricks quotes Lieutenant General

David McKiernan as saying: “In lieu of an order, or a frag (fragmentary) order, or

plan, you get a set of PowerPoint slides...at is frustrating because nobody wants

annoyance with PowerPoint became

evident when the person in commandof the third ACR in Iraq, Colonel H

R McMaster, decided to challengethe current military culture – in

Ricks’ words: “…all but banning theuse of PowerPoint briefings by his

offi cers. e army loves these bulletedbriefings, but McMaster had come to

believe that the ubiquitous software

inhibits clarity in thinking, expressionand planning.”

Well, it seems that Microsoft willneed to beef up its sales pitch to the

US military in the coming days, if Ricks’ claims are true. Or maybe just

train the offi cers to use PowerPointmore effectively.

to plan against PowerPoint slides.”Retired Colonel Andrew Bacevich

is quoted as being equally scathingin his criticism: “Here may be the

clearest manifestation of ... theassumption among forward thinkers

that technology—above all, informationtechnology—has rendered obsolete the

conventions traditionally governingthe conduct of war. To imagine that

PowerPoint slides can substitute forsuch means is really the height of

recklessness.”e extent of the military’s

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Cisco IP Telephony