1. Faiza Iqbal faizaiqbal@ceme.nust.edu.pk
Mobile Networks
Faiza Iqbal
EC-425 Mobile Networks Lab 1

2. Introduction to Wired and Mobile Network Devices
EC-425 Mobile Networks Lab 1

3. Network Components
EC-425 Mobile Networks Lab 1

4. Network Devices
EC-425 Mobile Networks Lab 1

5. Network Adaptors
Network adapter works as an interface between a computer or device and a network. You may need Ethernet, Wi-Fi, HomePNA, or HomePlug network adapter depending on the type of network your computer is connecting to. Network adapter converts a computer message into electrical or optical signals for transmission across the network. A network adapter is identified in a network through a MAC address that is hard-coded onto the hardware by its manufacturer.
EC-425 Mobile Networks Lab 1

6. Modem
Modem means modulator-demodulator. At the sending end, a modem modulates a carrier with the data (baseband signal) to prepare it for transmission. At the receiving end, the modulated carrier is demodulated (i.e. converted back to the original shape) and the data is extracted. There are many types of modulation techniques used in modem design, e.g. PCM, QPSK, QAM. A modem also performs other functions, such as digital-to-analog/analog-to-digital conversion, compression/decompression, error correction, and encryption/decryption.
You must connect your computer to a modem or install an internal modem inside your computer when you want to connect to the Internet. The type of modem that you need depends on the Internet access method that you choose. You may need a voiceband modem, a cable modem, an ADSL modem, or a GPRS modem. Your modem will communicate with the corresponding modem at your ISP during an Internet connection, transmit your computer message to the ISP (upstream), and receive Internet content forwarded by the ISP (downstream).
EC-425 Mobile Networks Lab 1

7. Repeaters
EC-425 Mobile Networks Lab 1

8. Repeaters (contd.) A repeater connects segments of LAN.
A repeater forwards every frame, it has no filtering capability.
A repeater is a regenerator not an amplifier.
EC-425 Mobile Networks Lab 1

9. Repeater (contd.)
EC-425 Mobile Networks Lab 1

10. Hub
Multiport Repeater
EC-425 Mobile Networks Lab 1

11. Bridges Two Functionalities
Filtering
Forwarding
A bridge has a table used in filtering decisions.
EC-425 Mobile Networks Lab 1

12. Bridge (contd.)
EC-425 Mobile Networks Lab 1

13. Switch
A combination of hub and bridge
EC-425 Mobile Networks Lab 1

14. Example of Local Area Network(LAN)
EC-425 Mobile Networks Lab 1

15. Example of LAN
EC-425 Mobile Networks Lab 1

16. Access Point
Access point in wireless LAN (Wi-Fi) functions like a hub or a switch in wired network. It connects computers or devices together to create a wireless network. Most wireless access points also function as a network bridge that connects the Wi-Fi network to a wired network such as Ethernet. An access point has an interface to a broadband modem or a router that is used when the Wi-Fi network connects to the Internet. Some access points come as a multi-function device that incorporates the functions of switch, bridge, router, or broadband modem. You may have heard about wireless router which is an access point that has a built-in router. Access point is also known as base station.
EC-425 Mobile Networks Lab 1

17. Routers
Connects a LAN to a WAN or a WAN to a WAN
Because a router has to make wide area network routing decisions, router has to dig down into the network layer of the packet to retrieve the network destination address
Thus, routers are often called “layer 3 devices”
They operate at the third layer, or OSI network layer, of the packet
EC-425 Mobile Networks Lab 1

18. Network Topologies
EC-425 Mobile Networks Lab 1

19. Physical Topologies
EC-425 Mobile Networks Lab 1

20. LAN Internetworking in Action: A small Office Revisited
A small office with 20 workstations in Technical Services Room and 15 workstations in Administrative Room were connected to a server via 100BaseTX
One hub was kept in a closet near the 20 workstations while a second hub was near the server
EC-425 Mobile Networks Lab 1

21. Example (contd.)
EC-425 Mobile Networks Lab 1

22. Example (contd.)
Now Network Administrator wants to connect the LAN to the Internet
She adds a router next to the server and connects it to the hub
She connects the router to a high-speed telephone line such as a T-1 service
She will also have to program the router to perform IP addressing and firewall functions
EC-425 Mobile Networks Lab 1

23. Example (contd.)
EC-425 Mobile Networks Lab 1

24. Example (contd.)
Now network usage is so high that Network Administrator must consider segmenting the network
She decides to install a database server near the original server and replace both hubs with switches
EC-425 Mobile Networks Lab 1

25. Example (contd.)
EC-425 Mobile Networks Lab 1

26. Summary
As LANs grow in size, and as the need to connect a LAN to other LANs and to WANs arises, it is necessary to understand how to interconnect similar and dissimilar networks
Reasons for interconnecting networks within a business include the need to interconnect two LANs from different departments or different geographic locations, to provide LAN users with access to the Internet or a legacy system, to segment a network that is growing too quickly, to provide a level of security between two application groups, and to provide a means of sharing software and peripherals
EC-425 Mobile Networks Lab 1

27. Summary (contd.)
Reasons for interconnecting networks within home include the need to share software, peripherals, and Internet connections
Four devices can provide varying levels of interconnection: hubs, bridges, switches, and routers
Hub is device that interconnects multiple workstations within a LAN
Bridges are relatively simple devices that could interconnect two networks at medium access control sublayer
EC-425 Mobile Networks Lab 1

28. Summary (Contd.)
Operation of a switch is similar to the basic operation of a bridge
Routers interconnect LANs with WANs
EC-425 Mobile Networks Lab 1

29. Institutional Network
mail server
to external
network
web server
router
switch
IP subnet
hub
hub
hub
EC-425 Mobile Networks Lab 1

30. Assignment 1
Draw an institutional network diagram, by observing its network components. Use any network drawing tool e.g. SmartDraw etc
EC-425 Mobile Networks Lab 1