Internet: Where is it Going?

1. Internet: Where is it Going? Kumar N. Sivarajan ECE Department Indian Institute of Science Bangalore 560 012, India e-mail: kumar@ece.iisc.ernet.in Fax: 91-80-334-7791, Phone: 91-80-309-2658 Web: http://www.ece.iisc.ernet.in/~kumar/ February 26, 1999

2. Mr.KUMAR.: Mr.KUMAR.: Outline • Packetized voice • QoS • High-speed routers • Differentiation and pricing • Distance education Introduction to Web based Education, Indian Institute of Science

3. Internet: Salient Features • Packet-switched (telephony is circuit-switched) • Datagrams (each packet is independent) • Best-effort (no guarantees) Introduction to Web based Education, Indian Institute of Science

4. Circuit- versus Packet-Switching • Packet-switching is best-suited for short and/or bursty data transfers • Web browsing • Remote terminal access • Short emails and small file transfers • Circuit-switching is best-suited for long-lived and/or continuous data transfers • Voice/telephony • Video transmission • Large file transfers Introduction to Web based Education, Indian Institute of Science

5. Circuit- versus Packet-Switching (contd.) • But any network can support all (or most) traffic types (some inefficiently) • Data over a telephone network using a modem • Telephony over the Internet • Choice of circuit- or packet-switching depends on the dominant traffic • Traffic on the Internet is mostly data • Traffic on the telephone network is mostly voice Introduction to Web based Education, Indian Institute of Science

6. Integrated Networks • One network for all applications • Telephone network as the universal network • Works better if voice is the dominant traffic • Internet as the universal network • Works better if data constitute the dominant traffic • Trend: Overall data traffic volumes have exceeded, or will exceed, voice traffic volumes Introduction to Web based Education, Indian Institute of Science

7. Internet as the Universal Network • Internet, as is, works fine for delay-insensitive traffic • Few changes needed if e-mail is the main application • Enhancements needed to support voice, and other delay-sensitive traffic • Voice over the Internet • Voice is packetized • Loosely analogous to ``modems'' for data transmission in telephone networks • Each packet is sent over the Internet like a data packet • Voice packets are reassembled into a continuous stream at the receiver Introduction to Web based Education, Indian Institute of Science

8. Internet as the Universal Network (contd.) • To work well, voice packets must not be delayed much in the Internet • Works if the network is lightly loaded • Requires modifications to the Internet to work in moderate to heavily loaded conditions • Internet telephony is a reality but not widespread in the public Internet • Potential Trend: Internet telephony may partially substitute corporate PBX networks in companies with well-/over-engineered intranets Introduction to Web based Education, Indian Institute of Science

9. Classes of Service • Differentiate traffic types within the Internet • Voice (delay-sensitive) traffic is given priority over email (delay-insensitive) traffic • Reduces delay for voice (high priority) traffic • Works well if voice (high priority) traffic is not the dominant traffic • Proposed for use in the Internet (DiffServ) Introduction to Web based Education, Indian Institute of Science

10. Internet Access • Wireless access is gaining popularity • Convenience • On-road access to email through cell-phones • Mobile access is becoming a necessity • Globe-trotting executives • Mobile IP: Mobility solution at the IP or network layer • Mobility solutions at the TCP or transport layer Introduction to Web based Education, Indian Institute of Science

11. Quality of Service • Applications may start to request quality of service (QoS) guarantees • Delay should be  x milliseconds • Protocols needed to signal required QoS to routers along the path and the destination • ReSource reserVation Protocol (RSVP) • Routers need to implement appropriate scheduling to provide QoS • Requires successive packets in a stream/flow take the same path • Departure from traditional datagram view of routing Introduction to Web based Education, Indian Institute of Science

12. Routing and Forwarding • Next hop router for packet determined by destination IP address • Two components: • Route computation: fill up the routing table • Packet forwarding: look up the routing table • Innovations in forwarding enable high-speed routers • New algorithms • Identifying streams/flows and label-switching Introduction to Web based Education, Indian Institute of Science

13. Premium Services and Pricing • With different services, flat pricing may disappear • Users pay for what they want or get • Requires development of extensive management and billing software • Along the lines of telephone networks Introduction to Web based Education, Indian Institute of Science

14. Only one copy of each packet traverses a link Multicast Introduction to Web based Education, Indian Institute of Science

15. Distance Education • Distance education gaining rapid acceptance • Internet is a more accessible, interactive and cost-effective medium compared to television • One copy of each packet for each receiver increases required bandwidth • Solution: IP multicast • This lecture is being multicast on the Internet! Introduction to Web based Education, Indian Institute of Science

16. Summary of Trends • Packet telephony in corporate intranets • Wireless and mobile access • Fiber/WDM intercontinental backbones • QoS support in routers • Premium services • Distance education • Internet as the universal network Introduction to Web based Education, Indian Institute of Science