CCNA Training Center

CCNA training options are designed to learn and get you certified in less time and more cost effectively. There is an effective approach to training that goes well beyond a single book or video course.

Start with a CCNA study guide that covers all concepts and fundamentals. Then move into the lab and learn how to configure routing and switching from scratch. Finally last mile review and practice tests will get you ready for exam day.

CCNA Study Guide

How do you know what is more relevant from less relevant? There is a crazy amount of information to learn for CCNA certification based on seven knowledge domains and 100+ topics. Your time is valuable and there is already enough to learn.

CCNA Routing and Switching 200-125 is a top-rated certification guide with seven instructional modules. There is coverage of ICND1 100-105, ICND2 200-105 and CCNA 200-125. Prepare for CCNA certification in less time than with standard books or videos.

  • Top-Rated CCNA Study Guide
  • Prepare for Exams in Less Time
  • ICND1, ICND2, CCNA 200-125
  • Seven Instructional Modules
  • Network Protocol Operation
  • Troubleshooting Questions
  • CCNA Test Recommendations

New and updated topics include IPv6 addressing, MPLS, MLPPP, PPPoE, GRE, QoS and eBGP. In addition there is coverage of switch stacking, cloud services, SDN, 802.1x, APIC-EM and DHCP snooping. It is all designed to prepare you for passing the CCNA certification exam.

CCNA Lab Training

CCNA lab questions are worth approximately 40% of all exam points. Start your lab training with a configuration workbook based on all CCNA topics. The top-notch lab guide steps you through all CCNA configuration topics from global commands to more complex routing and switching topologies.

CCNA Switching Labs

Configuration Labs
Troubleshooting Labs
Simulation Labs

Last Mile Review

Consolidate all of your training with study notes for your last mile review. There is a lot to remember and not everything is as relevant. You want to hit the ground running and not waste time during the exam. CCNA whiteboard notes are available here for quick review days before going into the exam and can improve your performance significantly.

The study tool is designed for quick summary of protocol operation, concepts, features, addressing, design rules and configuration. There is a systems troubleshooting section as well with root cause analysis for common network problems. It is difficult to adequately summarize key information from months of course training and books. The exam review is made easier to refresh your knowledge and hit the ground running.

Sample Exam Whiteboard

Practice Tests

Select practice tests that will verify your knowledge and troubleshooting skills. Prepare to pass the CCNA exam on first attempt with timed practice tests that have simulation questions. All questions are typical of what is on the CCNA exam with all topics included for best results. Know what to expect and prepare yourself for the CCNA exam.

What is a CCNA SIM?

CCNA exam includes practical labs with questions based on a network topology. You are required to troubleshoot connectivity errors and/or configure devices. SIM questions account for approximately 40% of all points and essential to passing the CCNA exam. There are SIM questions included to learn troubleshooting skills with step-by-step explanation of proper root cause analysis.

Each practice test is based on the same pattern as the real exam with all topics, percentages, pass score, duration and number of questions. In fact, experienced candidates can pass the CCNA exam easily with well designed practice tests.

Udemy Practice Tests

Certification Testing Skills

Learn test-taking skills to improve your score on the CCNA exam. I have read comments where candidates have clicked Next on a SIM lab question not knowing it submits an answer with no navigation to a previous lab question. CCNA exam does not permit any end of test review either. AWS certification training is available here as well to enhance your skill set and get that next job.


Troubleshooting Network Systems

There are a variety of different techniques that are recommended for troubleshooting network problems. The idea is to isolate the error to a network device, fix the problem and verify that network connectivity is restored. Optionally, you can start with a Ping to the destination and quickly verify there is Layer 3 connectivity.

OSI Layer Approach

Host Connectivity

Host TCP/IP address settings are displayed with Windows ipconfig /all command output. Network administrator can verify the MAC address and operational status of network interface card (NIC) as well. The following is a list of common points to check when troubleshooting network errors.

  • Host TCP/IP settings are correct.
  • Host is on a common subnet with the default gateway assigned.
  • DHCP is enabled for hosts.
  • Static routes exist in both directions when no dynamic routing exists.
  • Any ACL that is filtering application ports.

Operational vs Administrative

Operational status is the running state of a network device. Administrative status is how the device is configured. The operational status confirms for example that an interface is up, switch port mode or routing table entries. They are listed with various IOS show commands from CLI. 

Network Interface States

There is no routing available unless Layer 1 and Layer 2 is working correctly on any network device. The possible interface states for network interfaces are up/up, up/down and administratively down / administratively down. The normal status of an Ethernet interface is up/up. The shutdown command would change interface status to administratively down. It is not possible to have line protocol in up state when the interface (Ethernet) is down (down/up).

Interface = Layer 1, Line protocol = Layer 2

     switch# show interfaces fastethernet1/1

Ethernet 1/1 up, Line Protocol up  (normal state)

Typical Interface Errors

Layer 1 = cabling, switch configuration mismatch (speed/duplex)

Layer 2 = encapsulation mismatch, spanning tree, clocking errors

Err-Disabled State

Cisco switch interfaces that are in err-disabled state cannot send or receive frames and are essentially shutdown. The cause is either operational or a configuration mismatch. The following are some typical causes of a network interface in err-disabled state:

  • Duplex mismatch
  • Port security violation
  • EtherChannel mismatch
  • UDLD errors
  • BPDU guard
  • Interface flapping

Duplex Setting

Gigabit Ethernet interface support full-duplex as a default setting. Network traffic is sent simultaneously in both directions to double the bandwidth available. That eliminates collisions and creates a collision domain per interface. The fact that there are no collisions increase throughput and decreases network latency.

Gigabit Ethernet eliminates collisions unless there is a configuration error or hardware issue. Collisions are caused most often when there is a duplex mismatch on connected interfaces. In addition collisions can occur when there is a bad network interface card (NIC) or cabling error. The switch increments collision counter error after sending 512 bits of a frame. Cisco recommends auto-negotiation (auto/auto) duplex setting on all switch interfaces to minimize network errors.

Duplex mismatches with a neighbor interface cause collisions, input errors, CRC error and slower performance. The cause of collisions on a broadcast domain (VLAN) instead of interfaces are typically the result of duplex mismatches and faulty network interface card (NIC). The most common cause of CRC and runts is collisions. Giant frames result from either a bad NIC card or an MTU configuration error


The following show commands display operational and configuration information for all enabled switch trunk interfaces. It includes both static trunk interfaces or DTP enabled dynamic trunks. There is no support for speed and duplex commands or auto-negotiation with 10 GE ports. The following are common causes of trunking errors:

  • Native VLAN mismatch
  • Access mode configured
  • VLAN pruning
  • Duplex / speed mismatch
  • Incorrect DTP mode

The following IOS show commands display the operational status of trunk interfaces for troubleshooting purposes:

            switch# show interfaces trunk

            switch# show interface switchport


The following interface settings must match on all member switch ports assigned to an EtherChannel bundle. The channel-group number (1-48) bundles a port/s to a logical interface or port channel. Gigabit interfaces only support full-duplex traffic.

  • Duplex = half | full | auto
  • Speed = 10 | 100 | 1000 | auto
  • Protocol (PAgP, LACP or static)
  • Switch port mode (access or trunk)
  • VLAN membership
  • STP configuration
  • VLANs allowed (for trunk interfaces)
  • Native VLAN (for trunk interfaces)

VLAN Trunking Protocol (VTP)

  • Configure all switch uplink ports to trunk mode
  • Designate at least one VTP server
  • Configure all switches with the same VTP domain name
  • Configure all switches with the same domain password
  • VTP server or transparent mode is required to configure VLANs

Network Troubleshooting Course