WAN and Internet Access

1. WAN and Internet Access CP2073 - Networking

2. What is Wide Area Networking? How Internet access works Types of telecommunications services How to determine Internet access needs Steps in implementing a WAN connection Introduction CP2073 - Networking

3. What is Wide Area Networking? • A WAN is a network that is created using the services of the telephone company to connect LANs separated by large geographical distances • WANs require the use of special WAN protocols and devices • These protocols are usually part of a company’s Internet access • WANs introduce a new level of complexity to internetworking – such as coordinating with outside organisations eg your telecommunications provider CP2073 - Networking

4. WANs (2) • Characteristics are: • Connections are low bandwidth, with speeds from 56kbps to 2Mbps • A single Wan connection is shared by all devises on the LAN (bottleneck) – sometimes a second link is installed for the sake of redundancy • WANs cover a large geographical area • WAN technologies include Point-to-Point Protocol (PPP), Asynchronous Transfer Mode (ATM), ISDN, DSL, dial-up access and Frame Relay • WAN devices include routers, modems and WAN switches CP2073 - Networking

5. How Internet access works • Having set up the Internet at home you have in effect established a WAN CP2073 - Networking

6. Internet Access at Home • Initiate Dialup Software • Commands sent to modem • ISP is dialled • Modem uses ‘local loop’ – pair of copper wires • Signal goes to Local Exchange • A Switch forwards the call to the often distant ISP CP2073 - Networking

7. Internet Access at Home (2) CP2073 - Networking

8. Internet Access at Home (3) • Between the Exchange and the IPS is a multichannel trunk • Calls are multiplexed on that link • Calls are demultiplexed and separated to modems in a bank • The user’s modem and the modem in the bank handshake – a speed is established and data transferred • High speed Internet connections for a company is not too dissimilar to this CP2073 - Networking

9. Planning Internet Access • How will the connection be used ? • How important is the connection to the company ? • What infrastructure already exists ? • Balance need for bandwidth, reliability of connection, quality of service provider, quality of telco, cost • Future Applications ? • Video Conferencing/Streaming • E-Commerce • Virtual Private Network CP2073 - Networking

10. Telecommunications Services • Circuit Switching • ‘Creates’ channels as required • Essentially for voice data • Passive • Packet Switching • Transfer of data between two points over a shared medium • Sends packets across the network using the ‘best’ path • Burst-like in nature – an efficient solution • Cost is based upon usage CP2073 - Networking

11. WAN Technologies • Point-to-Point Protocol • Advantages • Well tested and implemented • Offers excellent throughput • Supports most network protocols • Simple to implement • Disadvantages • Less flexible for rapidly expanding multiple sites • ‘Expensive’ • Requires dedicated leased lines CP2073 - Networking

12. ISDN • Touted as the solution to residential and SMEs in the ’80s as a means of providing integrated data/voice • Due to costs has not been widely adopted • Advantages • Runs on existing phone lines • Supports voice, data and fax on one line • Good for video conferencing • Disadvantages • Comparatively expensive • Only provides 128K – can go up in multiples • Less flexible for growth and cost than other WAN technologies • Not available everywhere • Can be ‘difficult’ to implement CP2073 - Networking

13. Digital Subscriber Line (DSL) • ‘New’ technology • Best option for Residential/SME customers • Asymmetrical DSL (ADSL) and Symmetrical DSL • Advantages • Now becoming affordable • Good download speeds • Runs over normal copper line • Data and voice can be simultaneous • Disadvantages • ‘New’ means has yet to establish a reliability track record • Not available everywhere –BT have introduced satellite broadband (at a a price !) CP2073 - Networking

14. Data over Cable • Standard – Data Over Cable System Interface Specification (ITU-T J.112) • Known as cable-modem technology • Good Bandwidth/price ratio (cheap) • Provided by cable TV companies • Advantages • Speeds up to 10Mbps • Uses existing TV cable • Cheap • Disadvantages • Not available in all areas • Shared medium – speeds can drop CP2073 - Networking

15. Frame Relay • Introduced in 1992 • Communicates faster than X.25 (because it does not have error correction) • Advantages • Widely adopted, International • High Capacity switched core offers scalability • Flexible, allows expansion and growth • Disadvantages • Minimal error correction • Connection-oriented service, can cause latency on slow links • ‘Expensive’ CP2073 - Networking

16. What To look Out For • Do Research – Plan ! • Read the small print – what do you get for your money • ISP Setup Fee • Hardware Costs • Telecoms Installation Fee • Monthly/Annual Line Rental • No. of Fixed IP Addresses • Domain Name Service • Web Space • Email Addresses CP2073 - Networking

17. Moving To A New Service • No current service – employees have no expectations • New Service (Transition) • 99% Uptime expected • No downtime apparent to clients • All services to be moved to new ISP • Resolve problems of Domain Name, email, Web etc CP2073 - Networking

18. Plan • Establish contacts (names, phone, email) for all key players • Plan with your account manager at the new ISP • How long will InterNIC take to fulfill Domain Name Registrations • Order equipment well in advance, confirm delivery dates • Arrange check of new lines • Plan deployment of IP addresses • Install equipment – Check ! • Submit new registration to InterNIC • Move to the new ISP outside office hours CP2073 - Networking