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“Transforming Live, Inventing Future”

ASeminar Report On

GOOGLE VOICE

By

Swaruparani Sahu

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INDEX____________

1. Introduction 4

2. Features in Google Voice 6

3. Networking protocols involved 8

4. Benefits of Google Voice 14

5. Conclusion 15

6. References 16

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Introduction and History

Google Voice is a telecommunications service by Google launched on March 11, 2009. The service provides a US phone number, chosen by the user from available numbers in selected area codes, free of charge to each user account. Inbound calls to this number are forwarded to other phone numbers of the subscriber. Outbound calls may be placed to domestic and international destinations by dialing the Google Voice number or from a web-based application. Inbound and outbound calls to US (including Alaska and Hawaii) and Canada are free of charge. International calls are billed according to a schedule posted on the Google Voice website.

The service is configured and maintained by the user in a web-based application, styled after Google's e-mail service, Gmail. Users must have an established US telephone service to activate Google Voice. Users must configure this and optionally, additional phone numbers that ring simultaneously when the Google Voice number receives a call. The user may answer and receive the call on any of the ringing phones. Google Voice provides additional features such as voicemail, call history, conference calling, call screening, blocking of unwanted calls, and voice transcription to text of voicemail messages. Received calls may be moved between configured telephones during a call.

Google Voice is available only for users in the United States. Users may select a single US phone number from various area codes. Incoming

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calls to the number may ring simultaneously any of the user's configured phones or the account's Google Talk feature. Based on the calling number, or contact group (e.g., Family, Friends, Work), or on time of day, e.g., disabling a home phone during business hours and routing calls to mobile or business number, individual numbers may be configured to ring. The service also features voicemail with indexable automated voicemail transcription, accessible via a web browser, e-mail, or by phone. Google Voice provides automatic blocking of known numbers, e.g., telemarketers, the ability to switch lines in mid-call, differentiated voice mail greetings based on caller, SMS forwarding, and call recording. Additionally, customers of Gizmo5, a Session Initiation Protocol (SIP) service vendor, may forward calls to their Gizmo service which may be answered using a free computer application or a web application.

GrandCentral, founded in 2005 by Craig Walker and Vincent Paquet with funding by Minor Ventures, was acquired by Google on July 2, 2007, for US$95 million in a transaction led by Wesley Chan. On March 11, 2009, the management of the service revealed that the team had been working on it throughout that period, apparently in secret, and that it was being rebranded "Google Voice”.] It was to keep most of the functionality originally offered in GrandCentral and add new features

The following figure shows the interface of Google voice.

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Features in Google Voice

1. A single Google forwarding number to all of the user's phones

Using Google Voice we are able to establish a abstraction layer by providing a single “Google number” to the world, which underneath is connected to several telephone numbers at a time. Using such a feature enables the caller to ring all the phones of the person he/she is calling to ensure that the call is picked at any cost. This feature also enables a user to customize which phone to ring depending on the time of the day or the caller calling the number.

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2. Call screening

Announcement of callers based on their number or by an automated identification request for blocked numbers

3. Blocking calls from specified numbers

In an enhancement to the existing services provided by the telephony companies, Google voice allows handset independent blocking of calls from specific users. Those callers will hear a “number not in service” message when they call to the Google number of the said user.

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4. Send, receive, and store SMS online

Connecting the internet and the mobile phone has always been an objective of Google. Using Google Voice we can send and receive SMSes absolutely free of carrier charge. It also provides a facility to store the SMSes in form of email in your gmail account.

5. Voicemail transcripts

Voicemail is a feature using which we can hear audio messages of callers when we cannot pick up their calls. Google takes this feature a step further using which we can get a transcript of the voicemail delivered to our inbox and sms which we can read rather than listening.

Networking protocols involved

As with any internet telephony service, Google voice is primarily based on the Voice over Internet Protocol (VoIP) and coupled with the Session Initiation Protocol (SIP) in the application layer.

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1. Voice over Internet Protocol

Voice over Internet Protocol (Voice over IP, VoIP) is a general term for a family of methodologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms frequently encountered and often used synonymously with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.

Internet telephony refers to communications services — voice, fax, SMS, and/or voice-messaging applications — that are transported via the Internet, rather than the public switched telephone network (PSTN). The steps involved in originating an VoIP telephone call are signaling and media channel setup, digitization of the analog voice signal, optionally compression, packetization, and transmission as Internet Protocol (IP) packets over a packet-switched network. On the receiving side similar steps reproduce the original voice stream.

VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream. Codec use is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.VoIP can be a benefit for reducing communication and infrastructure costs. Examples include:

1. Routing phone calls over existing data networks to avoid the need for separate voice and data networks.

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2. Conference calling, IVR, call forwarding, automatic redial, and caller ID features that traditional telecommunication companies (telcos) normally charge extra for are available free of charge from open source VoIP implementations.

3. VoIP can facilitate tasks and provide services that may be more difficult to implement using the PSTN. Examples include:

4. The ability to transmit more than one telephone call over a single broadband connection.

5. Secure calls using standardized protocols (such as Secure Real-time Transport Protocol). Most of the difficulties of creating a secure telephone connection over traditional phone lines, such as digitizing and digital transmission, are already in place with VoIP. It is only necessary to encrypt and authenticate the existing data stream.

6. Location independence. Only a sufficiently fast and stable Internet connection is needed to get a connection from anywhere to a VoIP provider.

7. Integration with other services available over the Internet, including video conversation, message or data file exchange during the conversation, audio conferencing, managing address books, and passing information about whether other people are available to interested parties

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2. Session Initiation Protocol (SIP)

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The Session Initiation Protocol (SIP) is an IETF-defined signaling protocol, widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP). The protocol can be used for creating, modifying and terminating two-party (unicast) or multiparty (multicast) sessions consisting of one or several media streams. The modification can involve changing addresses or ports, inviting more participants, and adding or deleting media streams. Other feasible application examples include video conferencing, streaming multimedia distribution, instant messaging, presence information, file transfer and online games.

SIP was originally designed by Henning Schulzrinne and Mark Handley starting in 1996. The latest version of the specification is RFC 3261 from the IETF Network Working Group. In November 2000, SIP was accepted as a 3GPP signaling protocol and permanent element of the IP Multimedia Subsystem (IMS) architecture for IP-based streaming multimedia services in cellular systems.

The SIP protocol is an Application Layer protocol designed to be independent of the underlying transport layer; it can run on Transmission Control Protocol (TCP), User Datagram Protocol (UDP), or Stream Control Transmission Protocol (SCTP). It is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP).

SIP employs design elements similar to the HTTP request/response transaction model. Each transaction consists of a client request that invokes a particular method or function on the server and at least one response. SIP reuses most of the header fields, encoding rules and status codes of HTTP, providing a readable text-based format.

A motivating goal for SIP was to provide a signaling and call setup protocol for IP-based communications that can support a superset of

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the call processing functions and features present in the public switched telephone network (PSTN). SIP by itself does not define these features; rather, its focus is call-setup and signaling. However, it was designed to enable the construction of functionalities of network elements designated proxy servers and user agents. These are features that permit familiar telephone-like operations: dialing a number, causing a phone to ring, hearing ringback tones or a busy signal. Implementation and terminology are different in the SIP world but to the end-user, the behavior is similar.

SIP-enabled telephony networks can also implement many of the more advanced call processing features present in Signaling System 7 (SS7), though the two protocols themselves are very different. SS7 is a centralized protocol, characterized by complex central network architecture and dumb endpoints (traditional telephone handsets). SIP is a peer-to-peer protocol, thus it requires only a simple (and thus scalable) core network with intelligence distributed to the network edge, embedded in endpoints (terminating devices built in either hardware or software). SIP features are implemented in the communicating endpoints (i.e. at the edge of the network) contrary to traditional SS7 features, which are implemented in the network

The diagram next page clearly describes the working of the SIP protocol.

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Benefits of Google Voice

1. Lowering costs

Free calls and SMS International calls as low as $0.02 per minute

2. Managerial Benefits

Voicemail transcripts. Reading of voicemail messages online Downloading of voicemails. Call recording and online archiving. Blocking calls from specified numbers

3. Personal Benefits

Answering incoming calls on any configured phone Switching of phones during a call Conference calling Notification of voicemail messages via email or SMS

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Conclusion

Google has always tried to change the way we look at computing. And by creating the Google Voice application, the Mountain View giant has shown its intentions again.

Google Voice is the future of telephony as VoIP takes over traditional and orthodox telephony protocols.

The amount of services Google has been able to wrap with a free price tag itself is an example of cheaper technology enabling its access to all sections of the human society to improve its living standard.

Although Google Voice is currently available only in the US, it has plans of expanding its usage in the Asia Pacific within the next 8-10 months.

Its advent is surely revolutionary and with stiff competitors like Skype and Verizon in the market, the end user is surely going to benefit from all the rush.

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References

http://googlevoiceblog.blogspot.comhttp://googleblog.blogspot.com/2009/03/here-comes-google-voice.htmlhttp://www.crunchbase.com/product/google-voicehttp://lifehacker.com/tag/google-voice/http://www.crunchbase.com/product/google-voice