April 21, 2023 RE Meyers, Ms.Ed., CCAI

CCENT 640-822 ICND1 Exam Topics ReviewCCENT 640-822 ICND1 Exam Topics Review

Describe the Operation of Data Networks:

Network Diagrams and Data Paths

April 21, 2023

DisclaimerDisclaimer

This review is for the exclusive non-profit use by Cisco Academy instructors and students only!Contents of this review were derived from the following

sources under the doctrine of US copyright “Fair Use” section 107:

• Cisco Networking Academy Curricula: Discovery Networking for Home and Small Businesses version 4.x

• Interactive Course Guide, Cisco Learning Institute• CCENT/CCNA ICND 1 Official Exam Certification Guide, 2nd ed.

by Wendell Odom, Cisco Press, 2008; ISBN1-58720-182-2• Cisco Learning Network

https://learningnetwork.cisco.com/docs/DOC-4987• Other references footnoted in individual slide notes area.

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Error ReportingError Reporting

Please report any errors in this presentation to:remeyers@mail.wvu.eduDon’t rant! Let me know where I made a mistake so it can

be fixed. Feel free to modify this presentation to suit your needs.

• Please remove the WVU master and my name from your edited presentation to protect WVU’s logo acceptable use policy.

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CCENT Exam TopicsCCENT Exam Topics

 Describe the operation of data networksIdentify and correct common network problems at layer 1,

2, 3, and 7 using a layered model approach.

https://learningnetwork.cisco.com/docs/DOC-4987

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TroubleshootingTroubleshooting

Basic problem-solving procedure includes the following steps:1. Define the problem.

2. Isolate the cause of the problem.

3. Solve the problem.• Identify and prioritize alternative solutions.• Select one alternative as the solution.• Implement the solution.• Evaluate the solution.

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Structured TroubleshootingStructured Troubleshooting

Structured troubleshooting techniques include:Top-down Bottom-up Divide-and-conquer

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Structured TroubleshootingStructured Troubleshooting

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Alternate Troubleshooting ApproachesAlternate Troubleshooting Approaches

Trail and ErrorTroubleshooter makes an

educated guess on the most likely solution based on past experience and knowledge of the network structure

SubstitutionThe problem is assumed to

be caused by a specific hardware component or a configuration file, and it is replaced by a known good device or file

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OSI Model TroubleshootingOSI Model Troubleshooting

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Troubleshooting Using the OSI ModelTroubleshooting Using the OSI Model

Classify probable causes according to the OSI layer protocol.

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Layer 1: PhysicalLayer 1: Physical

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Layer 2: Data LinkLayer 2: Data Link

Check the Network Interface Most interfaces or NICs have indicator lights

• Link light shows if there is a valid physical connection• Other lights indicate whether traffic is being sent or received • If the interface has indicator lights that do not show a valid

connection, power off the device and reseat the interface card.

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Layer 2: Data LinkLayer 2: Data Link

Troubleshooting commands at router or switch

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Layer 3: Network Layer 3: Network

View TCP/IP settings using ipconfig or O/S network status of PC hostIP AddressSubnet MaskDefault Gateway

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Layer 3: NetworkLayer 3: Network

Check router for proper configurationIP AddressSubnet MaskRouting protocolsRouting table

Router# show ip protocols

Routing Protocol is "rip" Sending updates every 30 seconds, next due in 2 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Redistributing: rip Default version control: send version 2, receive version 2 Interface Send Recv Key-chain Ethernet0 2 2      trees Fddi0 2 2 Routing for Networks: 172.19.0.0 2.0.0.0 10.3.0.0 Routing Information Sources: Gateway Distance Last Update Distance: (default is 120)

Router# show ip route

Codes: I - IGRP derived, R - RIP derived, O - OSPF derived, C - connected, S - static, E - EGP derived, B - BGP derived, * - candidate default route, IA - OSPF inter area route, i - IS-IS derived, ia - IS-IS, U - per-user static route, o - on-demand routing, M - mobile, P - periodic downloaded static route, D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route, E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route, N2 - OSPF NSSA external type 2 route

Gateway of last resort is 10.119.254.240 to network 10.140.0.0

O E2 172.150.0.0 [160/5] via 10.119.254.6, 0:01:00, Ethernet2 E 172.17.10.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2 O E2 172.70.132.0 [160/5] via 10.119.254.6, 0:00:59, Ethernet2 O E2 10.130.0.0 [160/5] via 10.119.254.6, 0:00:59, Ethernet2 E 172.30.0.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2 E 10.129.0.0 [200/129] via 10.119.254.240, 0:02:22, Ethernet2

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Layer 3: NetworkLayer 3: Network

Trouble shooting commands include:Ping by IP and name to test connectivity and DNSTracert provides connectivity information about the path a

packet takes to reach the destination and about every router (hop) along the way.

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Layer 3: NetworkLayer 3: Network

arp –a Shows communication with other LAN devices, and

resolution of IP addresses to MAC

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Layer 4: TransportLayer 4: Transport

netstatDisplays TCP connections and ports, and UDP protocol

information.

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Layer 7: ApplicationLayer 7: Application

Verify that application software and parameters are configured properly.

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Layer 7: ApplicationLayer 7: Application

nslookupQueries Domain Name System (DNS) servers to find

DNS details, including IP addresses of a particular computer

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