National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [1] VoDSL: Next Generation Voice Solution Presented By Vinay Tibrewal Roll # EE Under the guidance of Mr. R.K. DASH Technical Seminar Presentation

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [2] DSL: An Introduction Stands for Digital Subscriber Line. Provides high speed Internet access through existing telephone lines. Doesn’t interfere with phone calls; Internet access and phone calls can be supported simultaneously. Doesn’t require a dial-up procedure before internet access. Flavors of DSL include ADSL, HDSL, VDSL, SDSL.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [3] VoDSL: An Introduction Stands for Voice over Digital Subscriber Line (DSL). Provides multiple telephone lines and high speed data services over a single access line. Allows for dynamic sharing of the DSL bandwidth between voice calls and data services. Provides the ability to purchase voice and data services from a single provider. Ideal for Small Businesses and Residential Users.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [4] VoDSL Architecture

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [5] VoDSL Architecture Customer Equipment: Telephones, private branch exchange (PBX), key system, fax, modem, and so forth. Integrated Access Device (IAD): Serves as the interface between the DSL network service and the customer’s voice and data equipment. Packetization of voice traffic takes place on this unit. DSL line: Transports the data and packetized voice to the nearest carrier facility. DSL Access Multiplexer (DSLAM): Terminate DSL lines from the customer premises and act as a backhaul facility for data and voice traffic from the subscriber.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [6] VoDSL Architecture (contd...) Voice Gateway: Receives voice traffic from the subscriber in packet format and efficiently reconstructs it to be received by the service provider’s Class 5 voice switch. Class-5 voice switch: Telephony switch providing dial tone, call routing, and services; also generates records used for billing. Public switched telephone network (PSTN): The public telephone network.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [7] Layered Architecture VoDSL has several layers: Physical layer: Actually a twisted pair of copper wires. Transport layer: Can be handled by frame relay, ATM, or Internet protocol (IP). Voice coding layer. Signaling layer. Services layer: Offer services from dial tone to call waiting.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [8] Transport Methods Within VoDSL Multiple options exist for the VoDSL Transport Network: ATM. Frame Relay (FR). IP. All of the above carry voice in packetized form to the destination. Each method has its own advantage: IP is the most prevalent packet based network today. Frame Relay is easy to implement. ATM provides the best Quality of Service (QoS).

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [9] IP For VoDSL Advantages of IP For VoDSL IP has ubiquity going for it. It is the most prevalent packet based network today. Can be mapped to any access technology, including ATM. Easier to interface with existing IP-enabled telephones. Disadvantages of IP For VoDSL IP is designed to provide only best effort service. It provides connectionless service to higher layers. Variable sized packets imply a higher latency. It’s not suitable for voice transfer. Cannot provide for Quality of Service guarantees. Intserv, Diffserv, RSVP and MPLS are still not widely deployed.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [10] ATM For VoDSL Advantages of ATM For VoDSL Designed to transmit diverse traffic types. Distinct classes of service available. Capable of supporting voice, video, and data transport over a common infrastructure. Designed to provide Quality of Service guarantees. Disadvantages of ATM For VoDSL ATM standards are emerging standards, not completely finalized.Voice over ATM standards are still emerging. ATM Standards are relatively more complex. ATM is not the best option for carrying Internet data, especially because of its cell tax. People are still not convinced about the basic cell design principle- small fixed size cell with 10% header overhead.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [11] Broadband Loop Emulation Service (BLES) Attaches to the Class 5 switch using well-known and proven standard interfaces. VoDSL Systems transparently derive voice services from Class 5 Dial tone, Voice Mail. Caller ID, Call wait, Call forwarding. Allocates bandwidth dynamically. Voice calls are given priority. Data calls using remaining bandwidth.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [12] Small Business Client LAN Ethernet ATM DSL CPE Internet Integrated voice and data Access Network Voice Provider POTS... Key System PSTN Voice Switch ( Class 5) Gateway ATM Switch DSLAM ATM Switch DSL Forum BLES Model

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [13] Voice over Broadband Networks Using soft switch technology to deliver value added services over DSL at the network edge. Class 5 switching architecture is expensive, and limits the ability of service providers to differentiate. MBN will support end-to-end data network connectivity for voice calls, bypassing the PSTN entirely.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [14] VoDSL Architecture - VoMBN

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [15] CONCLUSION The beauty of DSL technologies lies in its ability to enhance the capabilities of the existing copper lines to be able to transport voice and data services simultaneously. A single loop for both voice and data offers the cost advantage. Dynamic bandwidth allocation ensures that the circuit use is maximized at all times with voice precedence being honored. More standards work must be approved to further enhance the functionality of VoDSL services.

National Institute of Science & Technology Voice Over Digital Subscriber Line (VoDSL) Vinay TibrewalEE [16]