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Nt1210 Unit 7 Assignment 1

Presentation on theme: "NT1210 Introduction to Networking"— Presentation transcript:

1 NT1210 Introduction to Networking
Unit 7:Chapter 7, Wide Area Networks

2 ObjectivesIdentify the major needs and stakeholders for computer networks and network applications.Identify the classifications of networks and how they are applied to various types of enterprises.Explain the functionality and use of typical network protocols.Analyze network components and their primary functions in a typical data network from both logical and physical perspectives.2

3 ObjectivesDifferentiate among major types of LAN and WAN technologies and specifications and determine how each is used in a data network.Explain basic security requirements for networks.Use network tools to monitor protocols and traffic characteristics.Use preferred techniques and necessary tools to troubleshoot common network problems.Differentiate among WAN technologies available from service providers3

4 Objectives Evaluate how WAN devices function
Define and describe WAN protocolsEvaluate troubleshooting techniques for WAN connections4

5 Introducing Wide Area Networks: Basic Telco Services
Telephone, Telcos, and companies that grew from original Bell System impact how today’s WANs workTelcos built huge networks to support voice traffic, long before computers could create and send bitsTimeline Comparison of Inventions Compared to Telephone5Figure 7-1

6 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Early Voice: Telco Creates One Analog Electrical Circuit Between Phones6Figure 7-2

7 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Switched Analog Circuits for Data: To create first WAN connections, early computing devices had to act like telephonesOne computer device would “make phone call” to other computer, encoding its bits using analog electrical signals7

8 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Following the left-to-right example in the figure:The PC sends bits over a (short) cable to the modem.The modem converts the bits into analog electrical signals, with an encoding scheme that represents bits over time as different analog electrical signals (usually a different frequency).The analog signals arrives at the far side of the circuit, where:The modem translates back to a digital signal (bits).Connecting from a PC to an ISP, Using Modems and an Analog Telco Circuit8Figure 7-4

9 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Beginning mid-20th century Telcos transformedInvention and commercialization of computers: Started with few computers being rare and unusual to world where most companies owned computersMigration from Telcos as government monopolies to free- market competition: Governments started removing monopoly status from different parts of Telcos’ business so allowed competitionComputerization of Telco’s own network: Revolutionized how Telco built its internal network to create better services at lower cost9

10 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Digital Circuits and Leased Lines: Telcos started offering service that used digital circuit between customer devicesEndpoints still had circuit between them but could encode signal as bits with different electrical signals that followed encoding rulesMore Modern Routers Using a Digital Leased Line10Figure 7-5

11 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Switched Circuits and Circuit Switching: When user calls phone number, various circuit switches connect circuit on both sides of switch (see arrowed lines)Circuit switches create effect of end-to-end circuit by switching/connecting circuits on various linksCircuit Switching11Figure 7-6

12 Introducing Wide Area Networks: Basic Telco Services – Circuit Switching
Circuit: Communication path between two endpointsCircuit Switching: Logic used by Telco network and devices called “circuit switches” that allows them to switch circuits in and out of different physical trunks to create end-to-end circuit through networkSwitched Circuit: End-to-end circuit through Telco that changes over time because user calls number, hangs up, calls another number, and so onDedicated Circuit (leased line): Circuit between two specific devices Telco never takes down12

13 Introducing Wide Area Networks: Basic Telco Services – Packet Switching
Packet Switching: Telcos next started offering WAN services using packet switching servicesGeneral Timeline: Circuit Switching, Digital Circuits, and Packet Switching13Figure 7-7

14 Introducing Wide Area Networks: Basic Telco Services – Packet Switching
All customer devices need direct connection to WAN via circuit to packet switching serviceCustomers: All devices can send data to every other device connected to packet switched serviceTelco (service provider): Must look at meaning of bits in customer’s headers and make forwarding decision per packet14

15 Introducing Wide Area Networks: Basic Telco Services – Packet Switching
Packet Switching ExampleFor this example, the following steps occur:Router R1 (owned by the customer) sends a message, with a header that lists R2 as the destination address.Packet Switch A (owned by the WAN Service Provider) makes a choice to forward the message to packet switch B.Packet switch B (owned by the WAN Service Provider) makes a choice to forward the message to R2.Example of Packet Switching Service15Figure 7-8

16 Introducing Wide Area Networks: Routers
Connect LANs to WANsFollow the steps in the figurePC1’s IP logic tells it to send the IP packet to the nearby router (R1)R1’s IP logic tells it to make a routing decision, based on the destination IP address; that decision is to forward the IP packet over the WAN to router R2.R2’s IP logic tells it to make a routing decision, based on the destination IP address; that decision is to forward the IP packet over the LAN to host PC2.Layer 3 IP Forwarding Logic16Figure 7-9

17 Introducing Wide Area Networks: Routers
LAN might be simple Ethernet-only LANLAN might be simple WLANLAN might be more complex campus LAN with both wired and wireless LANsExample Enterprise Network, With LAN and WAN Details Revealed17Figure 7-10

18 Introducing Wide Area Networks: Routers
Encapsulation and De-encapsulationFollow the steps in the figure:PC1 sends an IP packet, inside an frame, to R1.R1 strips off the header and trailer, adds a WAN header and trailer, and forwards the frame over the WAN to R2.R2 strips off the WAN header and trailer, adds a new (different) header and trailer, and sends the frame to PC2.Encapsulation that Happens During the IP Packet Forwarding Process18Figure 7-11

19 Introducing Wide Area Networks: Topologies
Point-to-Point Topology: Basic WAN serviceLAN with10BASE-T or 100BASE-T cable has 2-pair: 1 pair for sending data in each directionBoth LAN and WAN topologies allow full duplex operation and can share 1 linkPoint-to-Point Topologies in WAN and LAN19Figure 7-12

20 Introducing Wide Area Networks: Topologies
Hub and Spoke TopologiesReduces number of leased linesProvides way for packets to reach all sitesConnects one router (hub router) to all other routers using leased linesWAN Hub and Spoke Topology Vs. LAN Star Topology20Figure 7-13

21 Introducing Wide Area Networks: Topologies
Multipoint topologies: Hub-and-spoke topology has some disadvantagesUses leased lines that might have to run hundreds or thousands of miles at large expensePackets that go from one spoke site to another spoke site have to cross multiple WAN linksWAN Multipoint Topology21Figure 7-14

22 Understanding Leased Line WAN Links
Distance limitations: No single circuit extends entire distance between two routers“Point to point” circuits really series of circuitsLeased Line: Shorter Electrical Circuits, Knitted Together22Figure 7-16

23 Understanding Leased Line WAN Links
Telco installs physical cable between equipment in CO to customer site2-pair cable typically runs underground into customer buildings terminating near customer’s routerCables in a Relatively Short Leased Line23Figure 7-18

24 Understanding Leased Line WAN Links
Customer needs to plan for cabling at end of Telco’s leased line cableExample: Customer’s router connects to cable installed by TelcoComponents and Responsibilities on One Side of a Leased Line24Figure 7-19

25 Understanding Leased Line WAN Links
Leased line has Channel Services Unit/Data Services Unit (CSU/DSU) function on each side of line at customer siteEach site uses either internal or external CSU/DSUInternal CSU/DSU sits inside router as part of serial interface cardCustomer Equipment and Cabling with External CSU/DSU25Figure 7-20

26 Understanding Leased Line WAN Links
Example: Cisco router with two slots for removable router interface cards (WICs) where serial cards are installSerial card on left has built-in CSU/DSU and uses RJ-48 connectorSerial card on right does not have CSU/DSU so relies on external CSU/DSU1921 router…WIC-1CSU:Photos of Router and Removable WAN Cards26Figure 7-22

27 Understanding Leased Line WAN Links
Key steps for installing leased linesOrder leased line from Telco; include specs on line speed, cable connectors required, and exact location where cable should be installed (address, floor, identifying information for exact room)Install router and serial interface cards in router as needed by leased lineIf interface card does not have internal CSU/DSU, choose CSU/DSU and matching cablePhysically connect all cablesConfigure devices (beyond scope of this chapter)27

28 BreakTake 1028

29 Understanding Leased Line WAN Links: Multiplexing
Possible solution: Telco could install three T1 trunk lines between CO switchesTelco Switching Connecting Incoming Customer T1s to T1 Trunks29Figure 7-24

30 Understanding Leased Line WAN Links: Multiplexing
More efficient solution: Time Division Multiplexing (TDM) uses TDM switches and one T3 trunkTelco connects cable using T3 card in each TDM switch to use T3 link ( Mbps—28 times T1 speed)CO Switches Multiplexing T1 Bits onto Faster T3 Circuit30Figure 7-25

31 Understanding Leased Line WAN Links
Customer buys T1 line at each site with full T1 speed (1.536 Mbps)What happens if customer router can only transmit at 768 Kbps?Speed Differences on a 768-Kbps Leased Line WAN31Figure 7-29

32 Understanding Leased Line WAN Links
Type of LineGeographySpeedNumber of ChannelsDS0USA64 KbpsN/ADS1 (T1)1.544 Mbps24 DS0DS3 (T3)Mbps28 DS1E0EuropeE12.048 Mbps32* E0E3Mbps16 E1J0JapanJ124 J0J3Mbps20 J1* 30 E0 channels are available for customer data; 2 E0 channels are for other functions.Summary of Carrier TDM Line Standards32Table 7-3

33 Understanding Packet Switching and Multi-Access WANs
With packet switching, link capacity between switches used to forward packets as needed or availableThe Telco, acting as a packet switching service, expects that over time, the total of all bits from all routers will not exceed a T3’s worth of bits.Router A1 sends its next message over its T1 link connects to Packet Switch 1.The header of the packet identifies router A2 as the destination.Packet Switch 1 looks at the destination address, and decides to send the packet out the T3 link (port 2) on the right.The same packet crosses the T3 link.The packet arrives at the second packet switch, which matches its forwarding table, sending the packet out port 4 towards router A233

34 Understanding Packet Switching and Multi-Access WANs: Frame Relay
Frame Relay: Allows any device connected to network to communicate with any other network and details of Frame Relay design do not matterTypical Drawing of a Frame Relay Design, One Customer, Ignoring Details34Figure 7-44

35 Understanding Packet Switching and Multi-Access WANs: Frame Relay
Frame Relay physical links: Edge between customer site and Frame Relay networkPoint of Presence (PoP): Where Telco devices/cables interface with customer premisesDTE (Data Terminal Equipment): Customer device (e.g., router)Frame Relay switch: Telco device that forwards customer frames (also called DCE [Data Communications Equipment])Access link: Physical link between DTE and DCEDLCI: Data Link Control Identifier, used instead of IP address35

36 Understanding Packet Switching and Multi-Access WANs: Frame Relay
Frame Relay termsOne Possible Telco Implementation of the Frame Relay Network36Figure 7-45

37 Understanding Packet Switching and Multi-Access WANs
Packet Switching Services: SONET speedsName(Rounded) Line Speed (in Mbps)OC-152OC-3155OC-12622OC-241244OC-482488OC-964976OC-1929952SONET Optical Carrier (OC) Names and (Rounded) Line Speeds37Table 7-5

38 Summary, This Chapter…Compared switched circuits as used for a typical home telephone call with two computers sending data over a similar switched circuit using modems.Explained the basic differences between a circuit switching WAN service and a packet switching WAN service from the customer’s perspective.Illustrated the reasons why IP routers work well at forwarding data between different types of LANs and WANs.Drew common WAN topologies.38

39 Summary, This Chapter…Drew and contrasted the different customer-site cabling for a leased line WAN installed between two routers.Listed the types of physical links in the US T-carrier hierarchy, their approximate speeds, and the specific number of slowed-speed channels that fit in the next higher-speed line.Explained how Telcos use CSU/DSUs to match a leased line speed to a physical DS1 line, using an example of a 768 Kbps fractional T1 leased line between two routers.Compared and contrast the HDLC and PPP standards.39

40 Summary, This Chapter…Explained the differences between packet switching and circuit switching from the Telco perspective.Used an example network, explain how with Frame Relay, a router can have one physical link connected to the WAN, but send data to many other destination routers.Listed the other WAN packet switching services, and show whether they were introduced before or after Frame Relay.40

41 Questions? Comments?41

42 Unit 7 Assignment Unit 7 Assignment 1: Wide Area Networks Review
Complete the multiple-choice questionsComplete the Define Key Terms table and the List the Words Inside the Acronyms table.Reading Assignment. Read Chapter 8

43 Unit 7 Lab Complete all Labs in Chapter 7 of the lab book.
Lab should be completed in class.Uncompleted Lab must be submitted in the next class.

44 Research ProjectUnit 7 Research Project 1: Chapter 8 Mind Maps (NT1210 Graded Assignments)

Essay on Computer Unit 1 assignment

812 WordsJan 5th, 20154 Pages

Kayja Billups

Professor Davidoff

CGS 1060C

6 January 2015

1. What is the difference between a software application and an operating system?
A computers operating system (OS) is the core of the computer and is more than just software. The OS controls the computer’s memory and processes as well as its hardware and software. It is the brain of the computer. Software applications on the other hand perform a certain task. Ex. Google Chrome provides internet and Adobe allows PDF files to be read (among other things). The OS is what makes all of these applications work successfully and accomplish whatever the application is designed to accomplish.

2. Describe a use for a software…show more content…

5. Why are software updates so important? Be sure to include security fixes, bugs, adaptation to new hardware availability and other plugin options.
Updating your software is crucial to the health of computer. Software updates provide fixes for any holes in your security as well as general bug fixes for your software to make it run more smoothly. Ex. Screen glitches, the OS being slow or lagging, etc. Sometimes when new hardware comes out an update to your OS and other software will be required in order to use the new hardware. Updates specific to your security software provide protection against new malware that has been found.

6. Give an example of a typical software update that you perform or that your computer provides for you. Be detailed in what software is being updated and whether it is automatic or if you are required to provide a disk or file.
Everytime Adobe Acrobat releases an update my computer pops up with a nessage asking if I want to update it now or later. It also gives me the option to check a box for automatic updates (updating without asking my permission). I am not required to provide a disk or file.

7. Attach 2 screenshots of a Windows screen, showing menus, toolbars, Windows, Folders, sub- folders, directories, subdirectories, and views. Change the view between the two screenshots. You can use PrintScreen (see the PrtSc key on your keyboard)

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