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Network Form and Function

Network Form and Function. Chapter 5. Chapter Objectives. Discuss forms of network. PAN, LAN, MAN, WAN, GAN Discuss asynchronous and synchronous communication. Discuss parameters for a network. Reliability, availability, security, and performance Discuss error correction and detection.

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Network Form and Function

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  1. Network Form and Function

    Chapter 5
  2. Chapter Objectives Discuss forms of network. PAN, LAN, MAN, WAN, GAN Discuss asynchronous and synchronous communication. Discuss parameters for a network. Reliability, availability, security, and performance Discuss error correction and detection. Checksum, echo-checking, LRC, VRC, and CRC Discuss network storage. SAN and NAS Prepared by SaherHasan Mohammed
  3. Forms of Network Based on the geographic location of the network devices and the computers, there are following network classification Personal Area Network (PAN). Local Area Network (LAN). Metropolitan Area Network (MAN). Wide Area Network (WAN). Galactic Area Network (GAN). Prepared by Saher Hasan Mohammed
  4. Personal Area Network (PAN) In PAN, the devices are physically very close to each other. Connecting the iPod to the computer. Connecting the cell phone to head phone via Bluetooth. Prepared by Saher Hasan Mohammed
  5. Personal Area Network (PAN) Prepared by Saher Hasan Mohammed
  6. Local Area Network (LAN) LAN covers an area of less of less than one kilometer in radius and connect people within an organization. LAN is a group of computers connected within a building or a campus. Campus Area Network, a variant of LAN, connects all the computers within a campus. LAN may consist of computers located on a single floor or a building or it might link all the computers in a small company. Prepared by Saher Hasan Mohammed
  7. Local Area Network (LAN) Prepared by Saher Hasan Mohammed
  8. Metropolitan Area Network A MAN is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of LAN’s using a high-capacity backbone technology, such as fiber-optical links. Prepared by Saher Hasan Mohammed
  9. Metropolitan Area Network Prepared by Saher Hasan Mohammed
  10. Wide Area Network A WAN is a network that covers a broad area, i.e., any network that links across metropolitan, regional, or national boundaries. In essence, this mode of network allows a business to effectively carry out its daily function regardless of location. Prepared by Saher Hasan Mohammed
  11. Wide Area Network Prepared by Saher Hasan Mohammed
  12. Galactic Area Network GAN uses radio to extend the networking capabilities to other bodies like moon, mars, weather satellites, etc. Prepared by Saher Hasan Mohammed
  13. Forms of Network Prepared by Saher Hasan Mohammed
  14. Connectivity in Networks The media/ channel/ wire used in the network will determine the bandwidth of the network. The three common forms of connectivity used are: Prepared by Saher Hasan Mohammed
  15. Asynchronize Communication The asynchronous communication technique is a physical layer transmission technique which is most widely used for personal computers providing connectivity to printers, modems, fax machines, etc. The unit of control is data byte or data character. The most significant aspect of asynchronous communications is that the transmitter and receiver clock are independent and are not synchronised. Prepared by Saher Hasan Mohammed
  16. Asynchronize Communication In fact, there need be no timing relationship between successive characters (or bytes of data). Individual characters may be separated by any arbitrary idle period. Prepared by Saher Hasan Mohammed
  17. Asynchronize Communication 8 Bit Character 10 Bit Character Frame P – Parity Bit S – Stop Bit Prepared by Saher Hasan Mohammed
  18. Synchronous Communication The unit of control is block of data, group of binary character. This block of data is called packet. Packet contains a header, payload (data) and trailer. The header include timing and address information. The payload is a group of data characters ( 1 to 1025 characters). Prepared by Saher Hasan Mohammed
  19. Synchronous Communication Trailer is added at the end, after the payload. Trailer contains the error checking code, called as block check characters (BCC’s). Sender and receiver clocks are synchronized. This mode is used to send large amount of data quickly, accurately and reliably. Prepared by Saher Hasan Mohammed
  20. Synchronous Communication Synchronous communication has two forms continuous synchronous communication and packet switch. Prepared by Saher Hasan Mohammed
  21. Parameters of a Valuable Network 1. Reliability Error Free Error Detection 2. Availability 24*7 Accessibility Prepared by Saher Hasan Mohammed
  22. Parameters of a Valuable Network 3. Performance Fixed Bandwidth Dynamic Bandwidth Bandwidth on demand Burst traffic 4. Security Physical Virtual Data Prepared by Saher Hasan Mohammed
  23. Power for Network Equipment Dirty Power: electrical power that has too many variations. Surge Protectors: power strips that regulates the high-voltage. Line Conditioning: use of electronics to take the incoming power and change it to conform to more rigid specifications. Prepared by Saher Hasan Mohammed
  24. Power for Network Equipment Uninterruptible power supply (UPS): this device stores electrical power, and uses it during the power outage. Backup-generators: petrol, diesel and gas powered engines generators that provide power in times of extended power outage. Prepared by Saher Hasan Mohammed
  25. Error Detection Common error detection techniques. Echo checking. Checksum. Parity checking or Vertical redundancy checking. Longitudinal redundancy checking. Cyclic redundancy checking. Echo Checking: echoing each transmitted character back from the receiving unit to the sending unit, via full-duplex capability. Prepared by Saher Hasan Mohammed
  26. Error Detection – Checksum Checksum: is a count of number of bytes in a transmission unit that are included with the unit so that the receiver can check to see whether the same number of bytes arrived. If the two numbers do not match, a negative acknowledgement is sent to the transmitter. Prepared by Saher Hasan Mohammed
  27. Error Detection - VRC Vertical redundancy checking or parity checking: is used in asynchronous communication. Two kinds of parity checking are used; even parity and odd parity. When even-1’s parity is used, the sending unit adds the numbers of 1’s in the data field and places a 0 or a 1 in the parity bit position to make the total number of 1’s an even quantity. Prepared by Saher Hasan Mohammed
  28. Error Detection - VRC The receiving unit performs the same count and compares the result with the value of the parity bit. VRC is universally used error detection technique, however it is very unreliable. Receiver Sender Receiver Sender NAK Receiver Sender Prepared by Saher Hasan Mohammed
  29. Error Detection - LRC Prepared by Saher Hasan Mohammed
  30. Error Detection - CRC Divide the data by a predetermined Divisor and calculate the Remainder and attach the Remainder at the end of data bits. Receiver will also divide the data bits with the same Divisor and calculates the Remainder and compares the received Remainder with the calculated one If they match, then no error detected. If no match, the error detected and the frame is deleted. Prepared by Saher Hasan Mohammed
  31. Error Detection - CRC Prepared by Saher Hasan Mohammed
  32. Error Correction Error correction techniques are used in synchronous communications. When the receiving unit detects an error in the block or packet, its requests that the sending unit retransmit the total data block. When an error is detected, a negative acknowledgement (NAK) is sent, and the data is retransmitted. If no error is detected, a positive acknowledgement (ACK) is sent. Prepared by Saher Hasan Mohammed
  33. Network Storage There are two major storage management technologies evolving to provide organizations the ability to store and manage the data. Network-attach storage. Storage area network. Prepared by Saher Hasan Mohammed
  34. Storage Area Network SAN is a high speed sub-network of shared storage devices. A storage device is a machine that contains nothing but a disk or disks for storing data. The server acts like an interface between the storage and the clients. Since the data do not reside on the server, the server power can be utilized for business applications. Prepared by Saher Hasan Mohammed
  35. Storage Area Network Prepared by Saher Hasan Mohammed
  36. Network Attach Storage The NAS is basically a system for file sharing that should have the software and the hardware preconfigured to make the network storage system. A NAS device is server that is dedicated to nothing more than file sharing. Instead of connecting directly to an individual desktop or laptop computer, a NAS device/server connects to the router. This effectively allows multiple users from multiple computers to access and share the content and files stored on it. Prepared by Saher Hasan Mohammed
  37. Network Attach Storage Prepared by Saher Hasan Mohammed
  38. Network Attach Storage NAS Benefits NAS uses existing network infrastructure. Simple implementation. Reduce total cost of ownership. Resource pooling. Improved manageability. Scalability. Connectivity. Heterogeneous file sharing. Enhanced choice. Prepared by Saher Hasan Mohammed
  39. Network Attach Storage NAS Drawback Consumption of LAN bandwidth. Data Integrity. Proliferation of NAS devices. Suitability for database storage. Software overhead impacting performance. Impact of backup/recovery application. Prepared by Saher Hasan Mohammed
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