CCNA 1. Networking Basics v3.1.1 Student Lab Manual (796248), страница 24
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An example in theabove network would be ping 10.36.13.101 -t and then press Enter.Be sure to use the Control-C command to stop the pings.ReflectionBased on observations made today, what could be deduced about the following results?Computer 1IP Address: 192.168.12.113Subnet Mask: 255.255.255.0Default Gateway: 192.168.12.1Pings and tracert to 207.46.28.116 were both successful.What will be the ARP table entry associated with this address and why?4-4CCNA 1: Networking Basics v 3.1 - Lab 9.3.7Copyright 2003, Cisco Systems, Inc.Lab 10.2.9 Small Router PurchaseObjectiveThe purpose of this lab is to introduce the variety and prices of network components in the market.This lab will look specifically at small routers used by telecommuters when working from home.
Thelab will use the web site http://www.cisco.com but any local source, catalog, or website can be used.Background / PreparationSome company executives want more secure connections when working with cable and DSLconnections from their homes. They have requested a proposal for purchasing small routers for thispurpose.
The assignment is to research at least two different solutions and develop a proposal. Theproject details are as follows:•The company IT department is interested in reliability.•There is concern about working with and supporting too many models of devices.•The company uses Cisco routers throughout the corporate network.•The company would like to be able to extend Cisco IOS features like Virtual Private Network(VPN) and firewall out to these remote users.In talking to the executives and support personnel, it has become apparent that some of thepersonnel live in areas that do not support DSL or cable service. Models that might also supportIntegrated Services Digital Network (ISDN) connections must now also be looked into.The requirements for the proposal include the following:1-2CCNA 1: Networking Basics v 3.1 – Lab10.2.9Copyright 2003, Cisco Systems, Inc.•12 routers supporting DSL or cable connections•3 routers supporting ISDN connections•All devices are to support the Cisco IOS featuresAssume the service provider will supply any required modem device and that the router will connectto it via an Ethernet interface.Several executives expressed an interest in being able to connect 2 or 3 computers to the same link.It is safe to assume this request will be made by most users.Step 1: Research equipment pricingStart by going to http://www.cisco.com and selecting Products & Services and following the links toRouters to gather basic information.
Look specifically at the 700, 800, and small office, home office(SOHO) models.Look at the Overview option, particularly any white papers, presentations, and brochures. These mayprovide useful data and graphics for the final presentation.Use at least three other sources for technologies and pricing. If using Web searches, tryhttp://www.cdw.com, http://www.google.com, or any other preferred search engine.Step 2: Compile a one-page summary of your resultsUse Microsoft Excel, Word, or any comparable products to compile a summary of the results. Includea short 8-15 line reason why this implementation was selected.
Include a simple diagram showingthe following:•Router•PCs•Power cord•Cable or DSL modemOptional Step 2Instead of creating the above Excel or Word documents, create a 4 to 8 slide PowerPointpresentation covering the same requirements.Assume that the material will need to be presented.If time allows, complete both step 2 and the optional presentation. This is a likely requirement formany jobs.2-2CCNA 1: Networking Basics v 3.1 – Lab10.2.9Copyright 2003, Cisco Systems, Inc.Lab 10.3.5a Basic SubnettingObjective•How to identify reasons to use a subnet mask•How to distinguish between a default subnet mask and a custom subnet mask•What given requirements determine the subnet mask, number of subnets, and hosts per subnet•What needs to be understood about useable subnets and useable numbers of hosts•How to use the ANDing process to determine if a destination IP address is local or remote•How to identify valid and invalid IP host addresses based on a network number and subnet maskBackground / PreparationThis lab exercise focuses on the basics of IP subnet masks and their use with TCP/IP networks.
Thesubnet mask can be used to split up an existing network into subnetworks, or subnets. Some of theprimary reasons for subnetting are the following:•Reduce the size of the broadcast domains, which creates smaller networks with less traffic•Allow LANs in different geographical locations to communicate through routers•Provide improved security by separating one LAN from anotherRouters separate subnets, and determine when a packet can go from one subnet to another. Eachrouter a packet goes through is considered a hop. Subnet masks help workstations, servers, androuters in an IP network determine if the destination host for the packet they want to send is on theirown network or another network.
This lab reviews the default subnet mask and then focuses oncustom subnet masks. Custom subnet masks use more bits than the default subnet masks byborrowing these bits from the host portion of the IP address. This creates a three-part address:•The original network address•The subnet address made up of the bits borrowed•The host address made up of the bits left after borrowing some for subnetsStep 1 Review the structure of IP addressesIf an organization has a Class A IP network address, the first octet, or 8 bits, is assigned and doesnot change.
The organization can use the remaining 24 bits to define up to 16,777,214 hosts on itsnetwork. This is a lot of hosts. It is not possible to put all of these hosts on one physical networkwithout separating them with routers and subnets.It is common for a workstation to be on one network or subnet and a server to be on another.
Whenthe workstation needs to retrieve a file from the server it will need to use its subnet mask todetermine the network or subnet that the server is on. The purpose of a subnet mask is to help hostsand routers determine the network location where a destination host can be found. Refer to the tablebelow to review the following information:1-7•The IP address classes•The default subnet masksCCNA 1: Networking Basics v 3.1 – Lab10.3.5aCopyright 2003, Cisco Systems, Inc.•The number of networks that can be created with each class of network address•The number of hosts that can be created with each class of network addressststAddressClass1 OctetDecimalRange1 OctetHighOrder BitsNetwork/Host ID(N=Network,H=Host)DefaultSubnet MaskNumberofNetworksA1 – 126 *0N.H.H.H255.0.0.0126 (2 –2)16,777,21424(2 – 2)B128 – 19110N.N.H.H255.255.0.016,38214(2 – 2)65,53416(2 – 2)C192 – 223110N.N.N.H255.255.255.02,097,15021(2 – 2)254 (2 – 2)D224 – 2391110Reserved for MulticastingE240 – 25411110Experimental; used for research7Hosts perNetwork(UsableAddresses)8* Class A address 127 cannot be used and is reserved for loopback and diagnostic functions.Step 2 Review the ANDing processHosts and routers use the ANDing process to determine if a destination host is on the same networkor not.
The ANDing process is done each time a host wants to send a packet to another host on anIP network. In order to connect to a server, the IP address of the server or the host name, such as,http://www.cisco.com, must be known. If the host name is used a Domain Name Server (DNS) willconvert it to an IP address.First, the source host will compare, or AND, its own IP address to its own subnet mask.
The result ofthe ANDing is to identify the network where the source host resides. It will then compare thenddestination IP address to its own subnet mask. The result of the 2 ANDing will be the network thatthe destination host is on. If the source network address and the destination network address are thesame, they can communicate directly. If the results are different, they are on different networks orsubnets.
If this is the case, the source host and the destination host will need to communicatethrough routers or might not be able to communicate at all.ANDing depends on the subnet mask. The subnet mask always uses all ones to represent thenetwork, or network + subnet, portion of the IP address. A default subnet mask for a Class C networkis 255.255.255.0 or 11111111.111111111.111111111.00000000.
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