Comptia Network+ N10 006 Chapter 1 Flashcards ionicons-v5-c

The 7 components to consider for forming a functioning network are?

client, server, hub, switch, router, media,and wide-area network (WAN) link. As

Client: define the term

The term client defines the device an end user uses to access a network.This device might be a workstation, laptop, smartphone with wireless capabilities,or a variety of other end-user terminal devices.

Server: define the term

Server: A server , as the name suggests, serves up resources to a network. Theseresources might include e-mail access as provided by an e-mail server, webpages as provided by a web server, or files available on a file server

Hub: define the term

Hub: A hub is an older technology that interconnects network components,such as clients and servers. Hubs vary in their number of available ports. However,for scalability, hubs can be interconnected, up to a point. If too manyhubs are chained together, network errors can result. As discussed further inChapter 3 , a hub is a Layer 1 device and does not perform any inspection of the traffic it passes. Rather, a hub simply receives traffic in a port (that is, a receptacleto which a network cable connects) and repeats that traffic out all ofthe other ports.

Switch: define the term

Switch: Like a hub, a switch interconnects network components, and they areavailable with a variety of port densities. However, unlike a hub, a switch doesnot simply take traffic in on one port and blast that traffic out all other ports.Rather, a switch learns which devices reside off of which ports. As a result,when traffic comes in a switch port, the switch interrogates the traffic to seewhere it is destined. Then, based on what the switch has learned, the switchforwards the traffic out of the appropriate port, and not out all the other ports.This dramatically cuts down on the volume of traffic coursing through yournetwork. A switch is considered a Layer 2 device, which means that it makes itsforwarding decisions based on addresses that are physically burned into a networkinterface card (NIC) installed in a host (that is, any device that transmitsor receives traffic on a network). This burned-in address is a Media AccessControl (MAC) address.

Router: define the term

Router: As discussed in Chapter 3 , a router is considered to be a Layer 3 device,which means that it makes its forwarding decisions based on logical networkaddresses. Most modern networks use Internet Protocol (IP) addressing.Therefore, most routers know what logical IP networks reside off of whichrouter interfaces. Then, when traffic comes into a router, the router examinesthe destination IP address of the traffic and, based on the router's database ofnetworks (that is, the routing table), the router intelligently forwards the trafficout the appropriate interface.

Media: define the term

Media: The previously mentioned devices need to be interconnected via somesort of media . This media could be copper cabling. It could be a fiber-opticcable. Media might not even be a cable, as is the case with wireless networks,where radio waves travel through the media of air. Chapter 3 expands on thisdiscussion of media. For now, realize that media varies in its cost, bandwidthcapacity, and distance limitation. For example, although fiber-optic cablingis more expensive than unshielded twisted-pair cabling, it can typically carrytraffic over longer distances and has a greater bandwidth capacity (that is, thecapacity to carry a higher data rate).

WAN link: Today, most networks connect to one or more other networks.For example, if your company has two locations, and those two locations areinterconnected (perhaps via a Frame Relay or Multiprotocol Label Switching[MPLS] network), the link that interconnects those networks is typicallyreferred to as a wide-area network (WAN) link. WANs, and technologies supportingWANs, are covered in Chapter 7 , "Wide-Area Networks."

Networks Defined by Geography(Name 5)

■Local-area network (LAN)■Wide-area network (WAN)■Campus-area network (CAN)■Metropolitan-area network (MAN)■Personal-area network (PAN)

LAN Define the term

LANA LAN interconnects network components within a local area (for example, withina building).

Examples of common LAN technologies you are likely to encounter? (name 2)

Examples of common LAN technologies you are likely to encounterinclude Ethernet (that is, IEEE 802.3) and wireless networks (that is, IEEE 802.11).Figure 1-2 illustrates an example of a LAN.

WAN Define the term

A WAN interconnects network components that are geographically separated. Forexample, a corporate headquarters might have multiple WAN connections to remoteoffice sites.

Name 2 examples of WAN technologies.

Multiprotocol Label Switching (MPLS), Asynchronous TransferMode (ATM), and Frame Relay are examples of WAN technologies.

Star Topology

where the connected devices radiate out from a centralized aggregation point

Bus Topology

A topology that typically uses a cable running through thearea requiring connectivity. Devices that need to connect to the network then tapinto this nearby cable.

Characteristics of a Bus Topology

One cable is used per network segment.To maintain appropriate electrical characteristics of the cable, the cable requires a terminator (of a specific resistance) at each end of the cable.Bus topologies were popular in early Ethernet networks.Network components tap directly into the cable via a connector such as a T connector or a vampire tap.

Benefits of a Bus Topology

Less cable is required to install a bus topology, as compared with other topologies.Depending on the media used by the bus, a bus topology can be less expensive.Installation of a network based on a bus topology is easier than some other topologies, which might require extra wiring to be installed.

Drawbacks of a Bus Topology

Because a single cable is use per network segment, the cable becomes a potential single point of failure.Troubleshooting a bus topology can be difficult because problem isolation might necessitate an inspection of multiple network taps to make sure they eitherhave a device connected or they are properly terminated.Adding devices to a bus might cause an outage for other users on the bus.An error condition existing onone device on the bus can impact performance of other devices onthe bus.A bus topology does not scalewell because all devices share the bandwidth available on the bus. Also, if two devices on the bus simultaneously request accessto the bus, an error condition results.

Characteristics of a Ring Topology

Devices are interconnected by connecting to a singlering or, in some cases (for example, FDDI), a dualring.Each device on a ring includes both a receiver (for the incoming cable) and a transmitter (for the outgoing cable) Each device on the ring repeats the signal it receives.

Benefits of a Ring Topology

A dual ring topology adds a layer of fault tolerance. Therefore, if a cable break occurred, connectivity to all devices could be restored.Troubleshooting is simplified in the event of a cable break,because each device on a ring contains a repeater. When the repeater on the far side of a cable break does not receive any data within a certain amount of time, it reports an error condition (typically in the form of an indicator light on a network interface card [NIC]).

Drawbacks of a Ring Topology

A break in a ring when a single ring topology is used results in a network outage for all devices connected to the ring.Rings have scalability limitations. Specifically, a ring has a maximum length and a maximum number of attachedstations. Once either of these limits is exceeded, a single ring might need to be divided into two interconnected rings. A network maintenance window might need to be scheduled to perform this ring division.Because a ring must be a complete loop, the amountof cable required for a ring is usually higher than the amount of cable required for a bus topology serving the same number of devices.

Characteristics of a Star Topology

Devices have independent connections back to a central device(for example, a hub or a switch).Star topologies are commonly used with Ethernet technologies (described in Chapter 4 ).

Benefits of a Star Topology

A cable break only impacts the device connected via thebroken cable, and not the entire topology.Troubleshooting is relatively simple because a central device in the star topology acts as the aggregation point of all the connected devices.

Drawbacks of a Star Topology

More cable is required for a star topology, as opposed to bus or ring topologies because each device requires its own cable to connect back to the central device.Installation can take longer for a star topology, as opposed to a bus or ring topology, because more cable runs that must be installed.

Characteristics of a Hub-and-Spoke WAN Topology

Each remote site (that is, a spoke) connects back toa main site (that is, the hub) via a WAN link.Communication between two remote sites travelsthrough the hub site

Benefits of a Hub-and-Spoke WAN Topology

Costs are reduced (as compared to a full-mesh or partial-mesh topology) because a minimal number of links is used.Adding one or more additional sites is easy (as compared to a full-mesh or partial-mesh topology) because only one link needs to be added per site.

Drawbacks of a Hub-and-Spoke WAN Topology

Suboptimal routes must be used between remote sites because all intersite communication must travel via the main site.Because all remote sites converge on the main site, this hub site potentially becomes a single point of failure.Because each remote site is reachable by only a single WAN link, the hub-and-spoke topology lacks redundancy

What is the formula to determine the number of required WAN connections in a Full-Mesh Network?

The number of required WAN connections can be calculated with the formula w = n * ( n - 1) / 2,where w = the number of WAN links and n = the number of sites.For example, a network with 10 sites would require 45 WAN connections to form a fully meshed network: 45 = 10 * (10 - 1) / 2.

Characteristics of a Full-Mesh WAN Topology

Every site has a direct WAN connection to every other site.The number of required WAN connections can be calculated with the formula w = n * ( n - 1) / 2,where w = the number of WAN links and n = the number of sites.For example, a network with 10 sites would require 45 WAN connections to form a fully meshed network: 45 = 10 * (10 - 1) / 2.

Benefits of a Full-Mesh WAN Topology

An optimal route exists between any two sitesA full-mesh network is fault tolerant because one ormore links can be lost and reachability between all sitesmight still be maintained.Troubleshooting a full-mesh network is relativelyeasy because each link is independent of the other links.

Drawbacks of a Full-Mesh WAN Topology

A full-mesh network can be difficult and expensive toscale, because the addition of one new site requires anew WAN link between the new site and everyother existing site.

Characteristics of a Partial-Mesh Topology

Selected sites (that is, sites with frequent intersite communication) are interconnected via direct links,whereas sites that have less-frequent communication can communicate via another site.A partial-mesh topology uses fewer links than a full-mesh topology and more links than a hub-and-spoketopology for interconnecting the same number of sites.

Benefits of a Partial-Mesh Topology

A partial-mesh topology provides optimal routesbetween selected sites with higher intersite traffic volumes,while avoiding the expense of interconnecting every site toevery other site.A partial-mesh topology is more redundant than a hub and-spoke topology

Drawbacks of a Partial-Mesh Topology

A partial-mesh topology is less fault tolerancethan a full-mesh topology.A partial-mesh topology is more expensive than a hub-and-spoke topology.

Characteristics of a Client/Server Network

Client devices (for example, PCs) share a common set of resources(for example, file or print resources) located on one or more dedicated servers.Resource sharing is made possible via dedicated server hardware and network operating systems.

Benefits of a Client/Server Network

Client/server networks can easily scale, which might require the purchase of additional client licensesAdministration is simplified, because parameters, such asfile sharing permissions and other security settings, can beadministered on a server as opposed to multiple clients

Drawbacks of a Client/Server Network

Because multiple clients might rely on a single server for their resources, the single server can become a single point of failure in the network.Client/server networks can cost more than peer-to-peernetworks. For example, client/server networks might require the purchase of dedicated server hardware and a network OS with an appropriate number of licenses.

Characteristics of a Peer-to-Peer Network

Client devices (for example, PCs) share their resources (forexample, file and printer resources) with other client devices.Resource sharing is made available through the clients' operating systems.

Benefits of a Peer-to-Peer Network

Peer-to-peer networks can be installed easily becauseresource sharing is made possible by the clients' operating systems, and knowledge of advanced NOSs is not required.Peer-to-peer networks usually cost less than client/server networks because there is no requirement for dedicatedserver resources or advanced NOS software.

Drawbacks of a Peer-to-Peer Network

Scalability is limited because of the increase administration burden of managing multiple clients.Performance might be less than that seen in a client/server network because the devices providing network resources might be performing other tasks not related to resource sharing (for example, word processing).