Breaking Down the New CCNA Exam: Network Fundamentals

by Jim Goughenour

This is the first in a series of articles on the six sections of Cisco’s CCNA certification exam 200-301, which earns the CCNA (Cisco Certified Network Associate) certification.

For those of you that are planning on taking Cisco’s 200-301 CCNA certification exam, there are some things that I think would be helpful for you to know.  I have written previously that Cisco took many of the Associate Level Exams (Route/Switch, Wireless, Security, Design) and combine them all into a comprehensive exam. In order to accomplish this, they have increased the number of questions and have broadened the scope of the questions asked during the exam. On the version of the exam I took not too long ago, there were about 100 questions and there was 2 hours given to complete the exam. Please be aware that just like in previous exams, once you select an answer or answers to a question and select next, you cannot go back for review or revision of your answer.

The 200-301 Exam blueprint is divided into 6 components, each component having a different weight associated with it.  Here are the categories, weights, and possibly the number of questions for each:

  • 1.0 Network Fundamentals – 20% – 20 questions
  • 2.0 Network Access – 20% – 20 questions
  • 3.0 IP Connectivity – 25% – 25 questions
  • 4.0 IP Services – 10% – 10 questions
  • 5.0 Security Fundamentals – 15% – 15 questions
  • 6.0 Automation and Programmability – 10% – 10 questions

What follows is a series of posts about each category. My hope is that this will be helpful in contributing to your success as you engage the exam. So let’s break it down. The first section of the exam is Network Fundamentals, which further breaks out like this:

1.1 Explain the Role and Function of network components

  • 1.1.a Routers
  • 1.1.b L2 and L3 Switches
  • 1.1 c Next-generation Firewalls and IPS
  • 1.1 d Access points
  • 1.1.e Controllers (Cisco DNA Center and WLC)
  • 1.1.f Endpoints
  • 1.1.g Servers

1.2 Describer characteristics of Network Topology Architectures

  • 1.2.a 2-Tier
  • 1.2.b 3-Tier
  • 1.2.c Spine-leaf
  • 1.2.d WAN
  • 1.2.e Small Office/Home Office (SOHO)
  • 1.2.f On-premise and Cloud

1.3 Compare physical interface and Cabling Types

  • 1.3.a Single-mode Fiber, Multimode Fiber, Copper
  • 1.3.b Connections (Ethernet Shared Media and point-to-point)
  • 1.3.c Concepts of PoE (Power over Ethernet)

1.4 Identify interface and cable issues (collisions, errors, mismatch duplex, and /or speed)

1.5 Compare TCP to UDP

1.6 Configure and verify IPv4 addressing and subnetting

1.7 Describe the Need for Private IPv4 Addressing

1.8 Configure and Verify IPv6 addressing and prefix

1.9 Compare IPv6 Address Types

  • 1.9.a Global Unicast
  • 1.9.b Unique Local
  • 1.9.c Link Local
  • 1.9.d Anycast
  • 1.9.e Multicast
  • 1.9.f Modified EUI 64

1.10 Verify IP parameters for Client OS (Windows, Mac OS, Linux

1.11 Describe Wireless Principles

  • 1.11.a Non-overlapping Wi-Fi Channels
  • 1.11.b SSID
  • 1.11.c RF
  • 1.11.d Encryption

1.12 Explain Virtualization Fundamentals (Virtual Machines)

1.13 Describe Switching Concepts

  • 1.13.a MAC Learning and Aging
  • 1.13.b Frame Switching
  • 1.13.c Frame Flooding
  • 1.13.d MAC Address Table

Before you panic, think about this for a moment. If there are roughly 100 questions on the exam, and Network Fundamentals comprises 20% of the exam, that means that there could be roughly 20 questions spread out about all the topics above. With that said, I thought I would try to give you some insight into the depth of some of the topics. All these topics are covered in the Implementing and Administering Cisco Solutions (CCNA v1.0) training class.

Explain the Role and Function of Network Components

The depth of the questions from this category are going to ensure you know the difference between a hub, an Ethernet Access Switch, and a Layer 3 or multilayer switch. It will reasonably expect that you know the difference between what an IPS does and what an IDS does as it relates to protecting the network. With regard to firewalls, a next-generation firewall, like FirePower, is a Layer 7 or deep packet inspection firewall that often has Intrusion Prevention System protection contained within the appliance. It also reasonably expects that you know that switches switch and routers route, and that they make decisions based on different parts of the IP header. It will expect you to know that an access point is basically a radio, usually controlled by a Wireless LAN Controller, unless of course it is an Autonomous AP, in which case it manages itself. Finally, endpoints and servers are, generally speaking, the sources or destinations of our network traffic, and that all the network components facilitate connection between them.

Describe Characteristics of Network Topology Architectures

Exam questions could be posed about what a collapsed Core architecture is, or why having a 3-tier architecture is preferred over a collapsed core architecture. There could be questions about the architecture of most data centers (Spine-Leaf) use in terms of fully redundant connections between the balance of the enterprise and the data center itself. Be prepared to answer questions about the different WAN options that are available (Point to Point, Ethernet, Serial, xDSL, Cable Modems, etc.) and what some of the advantages and disadvantages are when compared. SOHO, or Small Office/Home Office could comprise a question or two, and the primary difference between it and the balance of the Enterprise Network. And of course, there could be questions about the difference between what it means to have a service or appliance on-premise or in the cloud.

Compare Physical Interface and Cabling Types

If asked, know the basic difference between single mode and multi-mode fiber, how one has a broader core than the other, and how (without any kind of Multiplexing Function) multiple colors of light can pass through a multi-mode fiber as compared to a single mode fiber. Know also that single mode fiber can send or transport the light signals further without being repeated when compared to multi-mode fiber. Have a reasonable understanding of what Power over Ethernet (PoE) is and why we use it. (Hint: APs and VoIP phones use it). Also know that when using a hub or bridge, there is a common broadcast domain as compared to using a switch which provides for a point-to-point connection between the switchport and the device connected on the other side.

Identify Interface and Cable Issues

More than anything else in this part of the exam would be important to know what show command would give you traffic statistics as it relates to the FIFO queueing strategy a switchport uses to decide how to handle traffic flow as it comes across the interface. It also important to know what happens when one side is configured one way (speed/duplex) and the other side of the connection is configured differently.  Recall that in Cisco switches, there is a protocol that runs by default called Cisco Discovery Protocol and it will tell you if it senses a duplex mismatch. It would be helpful to know how to interpret the difference between up/down, down/down, administratively down/down, and up/up when it comes to looking at a switch.  Also, know the difference between a collision and an error, and what can cause both conditions.

Compare TCP and UDP

I can almost guarantee that there will be at least one question comparing and contrasting TCP with UDP.  Recall that TCP, or Transmission Control Protocol, is connection-oriented, offers guaranteed delivery, and has error-correction capability. UDP, or User Datagram Protocol, has none of these. Recall also that TCP has a much larger header than UDP, for all the control, and that UDP is faster than TCP as there is less to process at Layer 4 of the OSI Model.

Configure and Verify IPv4 Addressing and Subnetting

Some of you will glaze over this part of the preparation, and I could not be more emphatic when I tell you that among all the review sections of many books I have read, IPv4 addressing and subnetting is important to understand.  If I were to give you a network diagram with only one IPv4 address and mask, you will need to be able to pick the next IP address in that subnet (example: Router to Router ethernet interface connection, side A or Router A has IP address 199.4.1.145/30 (255.255.255.252), what would be the IP address of side B or Router B?) How many subnets can be created by borrowing 5 bits from the host field, and questions such as these are commonplace on the CCNA exam.

Describe the Need for Private IPv4 Addressing

Why do we have RFC-1918 addresses? What class of addresses are included in Private IPv4 addressing? To what end did we extend the utility of IPv4 addressing by making some of it private? What remains as Public IPv4 addressing? I would expect that there will be some questions on this topic as well.

Configure and Verify IPv6 addressing and Prefix

What in the world is an IPv6 address? Why are they so long? How do I configure a Cisco Router to speak the IPv6 language? How are they the same when compared to IPv4 addressing? Where did the Broadcast IPv6 address go? How do I configure routing for IPv6 and what are the different types of routing with IPv6? These are some of the question types that could be encountered.

Compare IPv6 Address Types

What is the difference between a link local, site local/unique local, and global unicast IPv6 address? What in the world is multicast mapping over Ethernet with IPv6? What is a solicited node multicast address? Where did broadcast addresses go in IPv6? Why is and what are the differences between an IPv6 header and an IPv4 header? Why is the Media Access Control address mashed onto the end of my global IPv6 unicast address and why is the 7th bit different? What do they mean when they say anycast? Although I would not expect a whole bunch of questions on this topic, I would expect at least some questions on the exam.

Verify IP Parameters for Client Operating System (OS)

If there are questions on the exam about how to do this, I think it wise to know the difference between ipconfig and ifconfig commands, and where you might use each. I would know (as I am sure most of you already do) that I can do this in the Command Line or in the Graphical User Interface of most endpoints.

Describe Wireless Principles

Do not feel the need to read an entire book about Wireless Technologies. The exam is going to ask some basic questions about the difference between 2.4GHz and 5.0GHz wireless radio spectrums and about how there are fewer available channels in the 2.4GHz spectrum than in the 5.0GHz spectrum. I would reasonably expect them to ask what three channels are non-overlapping in the 2.4GHz spectrum (Hint: 1, 6, and 11) and other questions about what is meant by the concepts of Service Set Identifier (SSID), Encryption, and Hashing. Remember that in most operating environments, there is a Wireless LAN Controller (WLC) and Access Points (AP) that create a wireless (sometimes also called Wi-Fi) environment for devices to connect and do work.

Explain Virtualization Fundamentals

What is a VM? How is it possible to have multiple VMs on a single physical appliance? What is the difference between a Type 1 Hypervisor and a Type 2 Hypervisor? What are some of the advantages of VMs? If asked, I think this to be about the depth of questions you will find on the exam.

Describe Switching Concepts

Earlier I said that switches switch and routers route. What I was saying was that switches learn MAC addresses on ingress and then build out a table to make decisions at Layer 2 of the OSI Model about how to forward frames. When a switch does not have a port-MAC address table entry, it floods the frame out all the ports so that it can learn where frames should go to reach their final destination. They also only keep the table entries for a specific period of time before those entries time-out (good luck with that in a Windows environment – it’s a chatty little operating system).  In any event, I would at least understand the basic function and behavior of an Access Switch. I can almost guarantee that there will be at least some questions about this subject.

In conclusion, I hope that the series of posts (5 more to go and posted below once published) will be helpful for you as you prepare. Know that I believe in you and have confidence that you will succeed. Happy examing everyone.

Training Resources:
Implementing and Administering Cisco Solutions (CCNA v1.0)
Athena Continuous Training Program
Enterprise Networking Training 

 

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