4 September 2015 RE Meyers, Ms.Ed., CCAI CCENT ICND1 Exam Topics Review Describe the Operation of Data Networks: Network Diagrams and Data Paths

4 September 2015 Disclaimer  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, 2 nd ed. by Wendell Odom, Cisco Press, 2008; ISBN Cisco Learning Network Other references footnoted in individual slide notes area.

4 September 2015 Error Reporting  Please report any errors in this presentation to:   Don’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.

4 September 2015 CCENT Exam Topics  Describe the operation of data networks  Identify and correct common network problems at layer 1, 2, 3, and 7 using a layered model approach.

4 September 2015 Troubleshooting  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.

4 September 2015 Structured Troubleshooting  Structured troubleshooting techniques include:  Top-down  Bottom-up  Divide-and-conquer

4 September 2015 Structured Troubleshooting

4 September 2015 Alternate Troubleshooting Approaches  Trail and Error  Troubleshooter makes an educated guess on the most likely solution based on past experience and knowledge of the network structure  Substitution  The 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

4 September 2015 OSI Model Troubleshooting

4 September 2015 Troubleshooting Using the OSI Model  Classify probable causes according to the OSI layer protocol.

4 September 2015 Layer 1: Physical

4 September 2015 Layer 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.

4 September 2015 Layer 2: Data Link  Troubleshooting commands at router or switch

4 September 2015 Layer 3: Network  View TCP/IP settings using ipconfig or O/S network status of PC host  IP Address  Subnet Mask  Default Gateway

4 September 2015 Layer 3: Network  Check router for proper configuration  IP Address  Subnet Mask  Routing protocols  Routing 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: 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 to network O E [160/5] via , 0:01:00, Ethernet2 E [200/128] via , 0:02:22, Ethernet2 O E [160/5] via , 0:00:59, Ethernet2 O E [160/5] via , 0:00:59, Ethernet2 E [200/128] via , 0:02:22, Ethernet2 E [200/129] via , 0:02:22, Ethernet2

4 September 2015 Layer 3: Network  Trouble shooting commands include:  Ping by IP and name to test connectivity and DNS  Tracert provides connectivity information about the path a packet takes to reach the destination and about every router (hop) along the way.

4 September 2015 Layer 3: Network  arp –a  Shows communication with other LAN devices, and resolution of IP addresses to MAC

4 September 2015 Layer 4: Transport  netstat  Displays TCP connections and ports, and UDP protocol information.

4 September 2015 Layer 7: Application  Verify that application software and parameters are configured properly.

4 September 2015 Layer 7: Application  nslookup  Queries Domain Name System (DNS) servers to find DNS details, including IP addresses of a particular computer

4 September 2015