1. CP2073 - Networking1 WAN and Internet Access

2. CP2073 - Networking2 Introduction What is Wide Area Networking? What is Wide Area Networking? How Internet access works How Internet access works Types of telecommunications services Types of telecommunications services How to determine Internet access needs How to determine Internet access needs Steps in implementing a WAN connection Steps in implementing a WAN connection

3. CP2073 - Networking3 What is Wide Area Networking? 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 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 WANs require the use of special WAN protocols and devices These protocols are usually part of a company’s Internet access 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 WANs introduce a new level of complexity to internetworking – such as coordinating with outside organisations eg your telecommunications provider

4. CP2073 - Networking4 WANs (2) Characteristics are: 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

5. CP2073 - Networking5 How Internet access works Having set up the Internet at home you have in effect established a WAN Having set up the Internet at home you have in effect established a WAN

6. CP2073 - Networking6 Internet Access at Home Initiate Dialup Software Initiate Dialup Software Commands sent to modem Commands sent to modem ISP is dialled ISP is dialled Modem uses ‘local loop’ – pair of copper wires Modem uses ‘local loop’ – pair of copper wires Signal goes to Local Exchange Signal goes to Local Exchange A Switch forwards the call to the often distant ISP A Switch forwards the call to the often distant ISP

7. CP2073 - Networking7 Internet Access at Home (2)

8. CP2073 - Networking8 Internet Access at Home (3) Between the Exchange and the IPS is a multichannel trunk Between the Exchange and the IPS is a multichannel trunk Calls are multiplexed on that link Calls are multiplexed on that link Calls are demultiplexed and separated to modems in a bank 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 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 High speed Internet connections for a company is not too dissimilar to this

9. CP2073 - Networking9 Planning Internet Access How will the connection be used ? How will the connection be used ? How important is the connection to the company ? How important is the connection to the company ? What infrastructure already exists ? What infrastructure already exists ? Balance need for bandwidth, reliability of connection, quality of service provider, quality of telco, cost Balance need for bandwidth, reliability of connection, quality of service provider, quality of telco, cost Future Applications ? Future Applications ? –Video Conferencing/Streaming –E-Commerce –Virtual Private Network

10. CP2073 - Networking10 Telecommunications Services Circuit Switching Circuit Switching –‘Creates’ channels as required –Essentially for voice data –Passive Packet Switching 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

11. CP2073 - Networking11 WAN Technologies Point-to-Point Protocol 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

12. CP2073 - Networking12 ISDN Touted as the solution to residential and SMEs in the ’80s as a means of providing integrated data/voice 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 Due to costs has not been widely adopted Advantages Advantages –Runs on existing phone lines –Supports voice, data and fax on one line –Good for video conferencing Disadvantages 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

13. CP2073 - Networking13 Digital Subscriber Line (DSL) ‘New’ technology ‘New’ technology Best option for Residential/SME customers Best option for Residential/SME customers Asymmetrical DSL (ADSL) and Symmetrical DSL Asymmetrical DSL (ADSL) and Symmetrical DSL Advantages Advantages –Now becoming affordable –Good download speeds –Runs over normal copper line –Data and voice can be simultaneous Disadvantages Disadvantages –‘New’ means has yet to establish a reliability track record –Not available everywhere –BT have introduced satellite broadband (at a a price !)

14. CP2073 - Networking14 Data over Cable Standard – Data Over Cable System Interface Specification (ITU-T J.112) Standard – Data Over Cable System Interface Specification (ITU-T J.112) Known as cable-modem technology Known as cable-modem technology Good Bandwidth/price ratio (cheap) Good Bandwidth/price ratio (cheap) Provided by cable TV companies Provided by cable TV companies Advantages Advantages –Speeds up to 10Mbps –Uses existing TV cable –Cheap Disadvantages Disadvantages –Not available in all areas –Shared medium – speeds can drop

15. CP2073 - Networking15 Frame Relay Introduced in 1992 Introduced in 1992 Communicates faster than X.25 (because it does not have error correction) Communicates faster than X.25 (because it does not have error correction) Advantages Advantages –Widely adopted, International –High Capacity switched core offers scalability –Flexible, allows expansion and growth Disadvantages Disadvantages –Minimal error correction –Connection-oriented service, can cause latency on slow links –‘Expensive’

16. CP2073 - Networking16 What To look Out For Do Research – Plan ! Do Research – Plan ! Read the small print – what do you get for your money 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

17. CP2073 - Networking17 Moving To A New Service No current service – employees have no expectations No current service – employees have no expectations New Service (Transition) 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

18. CP2073 - Networking18 Plan Establish contacts (names, phone, email) for all key players Establish contacts (names, phone, email) for all key players Plan with your account manager at the new ISP Plan with your account manager at the new ISP How long will InterNIC take to fulfill Domain Name Registrations How long will InterNIC take to fulfill Domain Name Registrations Order equipment well in advance, confirm delivery dates Order equipment well in advance, confirm delivery dates Arrange check of new lines Arrange check of new lines Plan deployment of IP addresses Plan deployment of IP addresses Install equipment – Check ! Install equipment – Check ! Submit new registration to InterNIC Submit new registration to InterNIC Move to the new ISP outside office hours Move to the new ISP outside office hours