Term
CCNA Section 1.2
An employee has the option of working from home, and their home is located in the same town as the main office. The only option available to connect to the main office is to use the internet. The employee sets up the network, consisting of one desktop computer and a printer. Which statements regarding the workers SOHO are correct? (Choose two.) |
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Definition
1. The SOHO network is integral to the main office network.
2. The SOHO network is an individual network that can function on its own.
3. The SOHO network devices, such as the desktop computer and a printer, must be connected to the internet to communicate.
4. SOHO needs a connection to the internet to access the enterprise resources located at the main office.
5. The SOHO is considered by the main office to be a local destination. |
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Term
CCNA Section 1.3
Which four of the following are network intermediary devices? (Choose four.) |
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Definition
1. tablet
2. temperature sensor
3. access point
4. firewall
5. laptop
6. switch
7. file server
8. wireless LAN controller |
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Term
CCNA Section 1.3
Network Devices
Devices can be further divided into endpoints and intermediary devices:
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Definition
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1. Endpoints: End devices, which are most common to people, fall into the category of endpoints. In the context of a network, end devices are called end-user devices, and include PCs, laptops, tablets, mobile phones, game consoles, and television sets. Endpoints are also file servers, printers, sensors, cameras, manufacturing robots, smart home components, and so on. At the beginning of computer networking, all end devices were physical hardware units. Today, many end devices are virtualized, meaning that they do not exist as separate hardware units any more. In virtualization, one physical device is used to emulate multiple end devices, for example all the hardware components that one end device would require. The emulated computer system operates as if it were a separate physical unit and has its own operating system and other required software. In a way, it behaves like a tenant living inside a host physical device, using its resources (processor power, memory, and network interface capabilities) to perform its functions. Virtualization is commonly applied for servers to optimize resource utilization, as server resources are often underutilized when they are implemented as separate physical units.
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2. Intermediary devices: These devices interconnect end devices or interconnect networks. In doing so, they perform different functions, which include regenerating and retransmitting signals, choosing the best paths between networks, classifying and forwarding data according to priorities, filtering traffic to allow or deny it based on security settings, and so on. As endpoints can be virtualized, so can intermediary devices or even entire networks. The concept is the same as in the endpoint virtualization—the virtualized element uses a subset of resources available at the physical host system. Intermediary devices that are commonly found in enterprise networks are:
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Switches: These devices enable multiple endpoints such as PCs, file servers, printers, sensors, cameras, and manufacturing robots to connect to the network. Switches are used to allow devices to communicate on the same network. In general, a switch or group of interconnected switches attempt to forward messages from the sender so it is only received by the destination device. Usually, all the devices that connect to a single switch or a group of interconnected switches belong to a common network and can therefore communicate directly with each other. If an end device wants to communicate with a device that is on a different network, then it requires "services" of a device that is known as a router, which connects different networks together.
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Routers: These devices connect networks and intelligently choose the best paths between networks. Their main function is to route traffic from one network to another. For example, you need a router to connect your office network to the internet. An analogy that may help you understand the basic function of switches and routers is to imagine a network as a neighborhood. A switch is the street which connects the houses, and routers are the crossroads of those streets. The crossroads contain helpful information such as road signs, to help you in finding a destination address. Sometimes, you might need the destination after just one crossroad, but other times you might need to cross several. The same is true in networking. Data sometimes "stops" at several routers, before it is delivered to the final recipient. Certain switches combine functionalities of routers and switches and they are called Layer 3 switches.
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APs: These devices allow wireless devices to connect to a wired network. An AP usually connects to a switch as a standalone device, but it also can be an integral component of the router itself.
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WLCs: These devices are used by network administrators or network operations centers to facilitate management of many APs. The WLC automatically manages the configuration of wireless APs.
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Next-generation firewalls (NGFW): Firewalls are network security systems that monitor and control the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network, and another outside network, such as the internet, that is assumed not to be secure or trusted. The term next-generation firewall indicates a firewall that provides additional features to accommodate the newest security requirements. An example of such a feature is the ability to recognize user applications, for instance a game running inside an application, such as a browser, that is connected to Facebook.
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Intrusion Protection System (IPS): An IPS is a system that performs deep analysis of network traffic, searching for signs that behavior is suspicious or malicious. If the IPS detects such behavior, it can take protective action immediately. An IPS and a firewall can work in conjunction to defend a network.
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Management Services: A modern management service offers centralized management that facilitates designing, provisioning, and applying policies across a network. It includes features for discovery and management of network inventory, management of software images, device configuration automation, network diagnostics, and policy configuration. It provides end-to-end network visibility and uses network insights to optimize the network. An example of such centralized management service is Cisco DNA Center.
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Term
CCNA Section 1.4
What is a topology |
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Definition
Topology: A network topology is the arrangement of its elements. Topologies give insight into physical connections and data flows among devices. In a carefully designed network, data flows are optimized and the network performs as desired. |
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Term
CCNA Section 1.4
Bitrate or Bandwidth (Definition) |
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Definition
Bitrate or Bandwidth: Bitrate is a measure of the data rate in bits per second of a given link in the network. The unit of bitrate is bit per second (bps). This measure is often referred to as bandwidth, or speed in device configurations, which is sometimes thought of as speed. However, it is not about how fast 1 bit is transmitted over a link—which is determined by the physical properties of the medium that propagates the signal—it is about the number of bits transmitted in a second. Link bitrates commonly encountered today are one and 10 Gigabits per second (1 or 10 billion bits per second). 100-Gbps links are not uncommon either.
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Term
CCNA Section 1.4
Definition of Availability |
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Definition
Availability: Availability indicates how much time a network is accessible and operational. Availability is expressed in terms of the percentage of time the network is operational. This percentage is calculated as a ratio of the time in minutes that the network is actually available and the total number of minutes over an agreed period, multiplied by 100. In other words, availability is the ratio of uptime and total time, expressed in percentage. To ensure high availability, networks should be designed to limit the impact of failures and to allow quick recovery when a failure does occur. High availability design usually incorporates redundancy. Redundant design includes extra elements, which serve as back-ups to the primary elements and take over the functionality if the primary element fails. Examples include redundant links, components, and devices.
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Term
CCNA Section 1.4
Definition of Reliability |
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Definition
Reliability: Reliability indicates how well the network operates. It considers the ability of a network to operate without failures and with the intended performance for a specified time period. In other words, it tells you how much you can count on the network to operate as you expect it to. For a network to be reliable, the reliability of all its components should be considered. Highly reliable networks are highly available, but a highly available network might not be highly reliable—its components might operate, but at lower performance levels. A common measure of reliability is the mean time between failures (MTBF), which is calculated as the ratio between the total time in service and the number of failures, where not meeting the required performance level is considered a failure. Choosing highly reliable redundant components in the network design increases both availability and reliability.
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Term
CCNA Section 1.4
Definition of Scalability |
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Definition
Scalability: Scalability indicates how easily the network can accommodate more users and data transmission requirements, without affecting current network performance. If you design and optimize a network only for the current requirements, it can be very expensive and difficult to meet new needs when the network grows.
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Term
CCNA Section 1.4
Definition of Security. |
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Definition
Security: Security tells you how well the network is defended from potential threats. Both network infrastructure and the information that is transmitted over the network should be secured. The subject of security is important, and defense techniques and practices are constantly evolving. You should consider security whenever you take actions that affect the network.
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Term
CCNA Section 1.4
Availability = Uptime / uptime + downtime
Reliability Mean Time Between Failures (MTBF) =
time in service / # of failures |
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Definition
device_x Availability= 24 * 55 / 24 * 60 x 100 =
1320 / 1440 * 100 = 91.67 %
Device_X Reliability MTBF = 24 * 55 / 24 = 1320/24 =
55 Minutes |
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Term
CCNA Section 1.4
Quality of Service (QoS). |
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Definition
Quality of Service (QoS): QoS includes tools, mechanisms, and architectures, which allow you to control how and when network resources are used by applications. QoS is especially important for prioritizing traffic when the network is congested.
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Term
CCNA Section 1.4
Definition of Cost. |
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Definition
Cost: Cost indicates the general expense for the initial purchase of the network components, and any costs associated with the installation and ongoing maintenance of these components.
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Term
CCNA Section 1.4
Definition of Virtualization. |
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Definition
Virtualization: Traditionally, network services and functions have only been provided via hardware. Network virtualization creates a software solution which emulates network services and functions. Virtualization solves a lot of the networking challenges in today’s networks, helping organizations centrally automate and provision the network from a central management point.
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Term
CCNA Section 1.4
Which three statements about network characteristics are true? (Choose three.) |
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Definition
1. Bitrate is a measure of the data rate in bits per second of a given link in the network.
2. Scalability indicates how many devices there are currently on the network.
3. QoS tells you how well the network is defended from potential threats.
4. Availability is a measure of the probability that the network will be available for use when it is required.
5. Reliability indicates to what extent you can count upon network components to perform as they are expected to. |
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Term
CCNA Section 1.5
The following are the primary physical topology categories: |
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Definition
Bus: In a bus topology, every workstation is connected to a common transmission medium, a single cable, which is called a backbone or bus. Therefore, each workstation is directly connected to every other workstation in the network. In early bus topologies, computers and other network devices were connected to a central coaxial cable via connectors.
Ring: In a ring topology, computers and other network devices are cabled in succession and the last device is connected to the first one to form a circle or ring. Each device is connected to exactly two neighbors and has no direct connection to a third. When one node sends data to another, the data passes through each node that lies between them until it reaches the destination.
Star: The most common physical topology is a star topology. In this topology, there is a central device to which all other network devices connect via point-to-point links. This topology is also called the hub and spoke topology. There are no direct physical connections among spoke devices. This topology includes star and extended star topologies. In an extended star topology, one or more spoke devices is replaced by a device that has its own spokes. In other words, it is composed of multiple star topologies, whose central devices are connected between each other.
Mesh: In a mesh topology, a device can be connected to more than one other device. For one node to reach others there are multiple paths available. Redundant links increase reliability and self-healing. In a full mesh topology, every node is connected to every other node. In partial mesh, certain nodes do not have connections to all other nodes.
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Term
CCNA Section 1.6
Which two options represent the meaning of the label Gi2/1? (Choose two.) |
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Definition
1. The interface is a Gigabit Ethernet interface.
2. The interface is a FastEthernet interface.
3. There is more than one slot for interface cards on the hardware.
4. The device is a router.
5. The cable that is connected to this interface is a copper cable.
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Term
CCNA Section 1.7
To classify applications, their traffic, and performance requirements are described in terms of these characteristics: |
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Definition
Interactivity: Applications can be interactive or noninteractive. Interactivity presumes that for a given request a response is expected for the normal functioning of the application. For interactive applications, it is important to evaluate how sensitive they are to delays—some might tolerate larger delays up to practical limits, but some might not.
Real-time applications expect timely serving of data. They are not necessarily interactive. An example of a real-time application is live football match video streaming (live streaming) or video conferencing. Real-time applications are sensitive to delay.
Delay is sometimes used interchangeably with the term latency.
Latency refers to the total amount of time from the source sending data to the destination receiving it. Latency accounts for propagation delay of signals through media, time required for data processing on devices it crosses along the path, etc. Because of the changing network conditions, latency might vary during data exchange: some data might arrive with less latency then other. The variation in latency is called jitter.
Amount of data generated: There are applications that produce low quantity of data, such as voice applications. These applications do not require much bandwidth. Usually they are referred to as bandwidth benign applications. On the other hand, video streaming applications produce significant amount of traffic. This kind of application is also termed bandwidth greedy.
Burstiness: Applications that always generate a consistent amount of data are referred to as smooth or non-bursty applications. On the other hand, bursty applications at times create small amount of data, but they can change behavior for shorter periods. An example is web browsing. If you open a page in a browser that contains a lot of text, a small amount of data is transferred. But if you start downloading a huge file, the amount of data will increase during the download.
Drop sensitivity: Packet loss is losing packets along the data path, which can severely degrade the application performance. Some real-time applications (such as Video On Demand) are sensitive to the perceived packet loss when using the network resources. You can say that such applications are drop sensitive.
Criticality to business: This aspect of an application is "subjective" in that it depends on someone's estimate of how valuable and important the application is to a business. For instance, an enterprise that relies on video surveillance to secure its premises might consider video traffic as a top priority, while another enterprise might consider it totally irrelevant. |
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Term
CCNA Section 1.7
One way that applications can be classified is as follows: |
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Definition
Batch applications: Applications such as FTP and TFTP are considered batch applications. Both are used to send and receive files. Typically, a user selects a group of files that need to be retrieved and then starts the transfer. Once the download starts, no additional human interaction is required. The amount of available bandwidth determines the speed at which the download occurs. While bandwidth is important for batch applications, it is not critical. Even with low bandwidth, the download is completed eventually. Their principal characteristics are:
Typically do not require direct human interaction.
Bandwidth important but not critical.
Examples: FTP, TFTP, inventory updates.
Interactive applications: Applications in which the user waits for a response to their action are interactive. Think of online shopping applications, which are offered by many retail businesses today. The interactive applications require human interaction and their response times are more important than for batch applications. However, strict response times or bandwidth guarantees might not be required, so if the appropriate amount of bandwidth is not available, then the transaction may take longer, but it will eventually complete.
The main characteristics of the interactive applications are:
Typically support human-to-machine interaction.
Acceptable response times have different values depending on how important the application is for the business.
Examples: database inquiry, stock-exchange transaction
Real-time applications, such as voice and video applications, may also involve human interaction. Because of the amount of information that is transmitted, bandwidth is critical. In addition, because these applications are time critical, a delay on the network can cause a problem. Timely delivery of the data is crucial. It is also important that not too much data is lost during transmission because real-time applications, unlike other applications, do not retransmit lost data. Therefore, sufficient bandwidth is mandatory, and the quality of the transmission must be ensured by implementing QoS. QoS is a way of granting higher priority to certain types of data, such as Voice over IP (VoIP). The main characteristics of the real-time applications are:
Typically support human-to-human interaction.
End-to-end latency is critical.
Examples: Voice applications, video conferencing, and live sports event online streaming.
Applications may also be required to manage different types of communications. One such application is the factory-automation application. Factory-automation applications deal with plant process-related data, such as readings from sensors and alarms, which require guaranteed delivery times and typically require feedback within a prescribed response time. On the other hand, the same factory-automation application must also handle certain device configurations and commercial data, which is not time-critical. |
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Term
| You are given a physical network diagram. Which two statements about the logical diagram for the same network are true? (Choose two.) |
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Definition
The logical Diagram can be drawn by examining device configurations.
The Logical Diagram can be drawn by analyzing data flows in the network.
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Term
| What is the function of a WLAN controller? |
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Definition
To Automatically handle the configuration of a Wireless Access Point. |
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Term
| Which network characteristic would best describe how well the network would support business critical applications in case of an unexpected increase of traffic? |
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Definition
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Term
| What is the availability percentage over a one year period of the network that is not available for 15 minutes each month? |
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Definition
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Term
| Which network characteristic indicates the dependability of the components that make up the network? |
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Definition
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Term
| Which two statements about interface labels are true? (Choose two.) |
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Definition
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Term
CCNA Section 1.6
Which interface is defined in the S0/0/0 format? |
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Definition
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Term
CCNA Section 1.7
Match the type of process to the correct application. |
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Definition
Answer
VOIP : Realtime Application
FTP: Batch Application
Stock Exchange Transaction: Interactive Application |
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Term
CCNA Section 1 Questions:
You are given a physical network diagram. Which two statements about the logical diagram for the same network are true? (Choose two.)
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Definition
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Term
| What is the function of a WLAN controller? |
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Definition
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Term
Which network characteristic would best describe how well the network would support business critical applications in case of an unexpected increase of traffic? |
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Definition
Speed
Security
QoS
Reliability |
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Term
| What is the availability percentage over a one year period of the network that is not available for 15 minutes each month? |
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Definition
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Term
| Which network characteristic indicates the dependability of the components that make up the network? |
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Definition
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Term
| Which two statements about interface labels are true? (Choose two.) |
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Definition
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Term
| Which network characteristic indicates the general expense to purchase, install, and maintain network components? |
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Definition
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Term
| What is the function of a firewall? |
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Definition
| to monitor and control the incoming and outgoing network traffic. |
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Term
| In which type of applications does the user need to wait for a response when performing actions such as inventory lookup or a database update? |
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Definition
| interactive applications. |
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Term
| What are three examples of remote access locations? (Choose three.) |
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Definition
BRANCH OFFICES
Small Office / Home Office SOHO
A Network in an airport lounge |
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