Module 6

1. Module 6 Networking

2. Why Network? Despite the costs of implementation and maintenance, networks actually save organizations money by allowing them to: • Consolidate (centralize) data storage • Share peripheral devices like printers • Increase internal and external communications • Increase productivity and collaboration

3. Networking A networkis a group of computers that can share information through their interconnections. • Computers(nodes or hosts). • Transmission media provides a path for electrical signals between devices. • Network interfaces are devices that send and receive electrical signals. • Protocols are rules or standards that describe how hosts communicate and exchange data.

4. Networking

5. Protocols A protocol is a rule that identifies some aspect of how computers communicate on a network. For two computers to communicate, they must be using the same protocols.  Protocols are grouped into protocol suites, or sets of related protocols. • Virtually all operating systems today provide native (built-in) support for TCP/IP. • Most older versions of some operating systems used a different protocol as the default protocol suite. For example, older NetWare servers used IPX/SPX, while Mac OS systems used AppleTalk. • Older operating systems without native TCP/IP support enabled TCP/IP communications by either installing the protocol stack or through a process known as encapsulation or tunneling. With this process, non-TCP/IP packets are re-packaged as TCP/IP packets at the sending device. The receiving device strips off the TCP/IP headers to reveal the original packets.

6. Protocols

7. Protocols

8. Addressing Network devices use addresses to identify other devices. These addresses are used to send and receive packets of electronic data over the network. The addresses used depend on the physical make-up of the network as well as the protocol suite being used. Each network device is identified using a: • physical address or MAC (like a serial number) • logical network address (subnet) identifies a network segment. • All devices on the same network segment share the same logical network address. • logical host address (name) identifies a specific host on the network. • Each device must have a unique logical host address.

9. Physical Addressing (MAC) Each network device is identified using a physical address. Ethernet networks use a MAC Address (physical device address) • The MAC address is a unique hexadecimal identifier burned into the ROM (physically assigned address) of every network interface. • When you change the network card, the host will have a new physical device address. • When you move a device to another network, the physical address remains the same (as long as the network card has not been changed). • The MAC address is guaranteed unique through design. • The first half (first 6 digits) of the MAC address is assigned to each manufacturer. • The manufacturer determines the rest of the address, assigning a unique value which identifies the host address.

10. Logical Network Address With TCP/IP, the logical network and logical host addresses are combined into a single address called the IP address. • An IP address is a 32-bit binary number represented as four octets (four 8-bit numbers). Each octet is separated by a period. • Asubnet mask is used to differentiate the network and host addresses. • Each IP address has a default class that includes a default subnet mask value. The class defines the default network address portion of the IP address. • For example, an IP address of 192.168.6.11 with a default mask of 255.255.255.0. The network address is 192.168.6.0 and the host address is 11. • Instead of using the default subnet mask, you can use custom subnet masks to define different network addresses. This process is called subnetting. Note: The address range from 0.0.0.0 to 0.255.255.255 is reserved for broadcast messages to the current network. The address range from 127.0.0.0 to 127.255.255.255 is reserved for loopback addresses to the local host.

11. Logical Host Address • Humans remember names (or hostnames) much easier than numbers (especially binary numbers). • A hostname is a label (name) assigned to a device connected to a computer network. • Hostnames are used to identify the device in a Domain Name System (DNS) such as the World Wide Web. • Hostnames that include DNS domains are often stored in the Domain Name System together with the IP addresses of the host they represent for the purpose of mapping the hostname to an address, or the reverse process.

12. Networking Devices

13. Networking Devices

14. Networking Devices

15. Networking Devices

16. Networking Standards

17. Networking Standards

18. Coaxial Cable Coaxial cable is an older technology that is usually implemented with a bus topology. Advantages • Highly resistant to Electromagnetic Interference (EMI) • Highly resistant to physical damage Disadvantages • Expensive • Inflexible construction (difficult to install) • Unsupported by newer networking standards

19. Twisted Pair cable Twisted pair cables support a wide variety of fast, modern network standards Advantages • Inexpensive compared to other media types • Easy to install and manage • Very common (media and tools are easy to obtain) Disadvantages • Most susceptible to EMI of all the media types • Cables are more easily damaged than other types

20. Fiber Optic Cable With fiber optic cabling the plastic or glass core carries the signal. Advantages • Totally immune to Electromagnetic Interference (EMI) • Highly resistant to eavesdropping • Supports extremely high data transmission rates • Allows greater cable distances without a repeater Disadvantages • Very expensive • Difficult to work with and requires special training