Flashcards
Module 11
Flashcards do conjunto (20)
- 1EXPLAIN LAN & ADVANTAGES/DISADVANTAGES?Local Area Networks(LAN) is a network of computers and other components located relatively close together(usually within the confines of a single building). Enterprise LAN will be much larger(e.g. 1000's of computers, 100 printers, etc) & SOHO LAN's(e.g. 3 computers, 1 printer).
ADVANTAGES:
-Resource sharing(printers, drivers, internet, software)
-Commnication(easy - same address configuration, fast - protocols and network cabling, time-saving in accessing resources remotely)
DISADVANTAGES:
-Security(unauthorized access can be granted if not setup correctly)
-Distance limitation(Generally limited to a single building)
-Setup costs(need to purchase all the hardware/software) - 2EXPLAIN WAN?Wide Area Network(WAN) is the opposite of LAN. WANs are used to transfer data across large distances, commonly used to connect multiple LANs together(e.g. an organization has multiple physical locations that are geographically separated, WAN can connect each of those locations). WAN uses a different protocol than LAN(including PPP(point to point protocol), Frame Relay, or ATM(asynchronous transfer mode), all depending on what your needs are). LANs are typically owned by the organization where a WAN is generally a subscription service from some kind of service provider who already has the infrastructure as expensive to implement their own WAN.
It is a different type of network so there are different types of protocols & hardware used. Networks with different services & speeds, performant & prices include:
- Integrated Service Digital Network(ISDN)
- Switched Multimegabit Data Service(SMDS)
- Synchronous Optical Network(SONET)
- Synchronous Data Link Control(SDLC)
- High-level Data Link Control(HDLC)
-Frame Relay
- Ethernet(the protocol, not the cable) - 3WAN ADVANTAGES/DISADVANTAGES?ADVANTAGES:
-Covers a large geographical area
-Allows you to implement Centralized data(so data may all reside in corporate headquarters, but the branch offices can access it centrally)
-Sharing(software/resources across WAN)
-High bandwidth(is offered)
DISADVANTAGES:
-Security(mix of different technologies can create a security gap, as certain features may not be supported by both technologies when moving from one protocol and one physical type of technology to another)
-Setup costs(need to purchase routers, certain types of switches in some cases, and security software also has to be implemented while the data is traversing the WAN, so that its not picked up by anyone on the public internet) - 4EXPLAIN PAN & ADVANTAGES/DISADVANTAGES?PERSONAL AREA NETWORK(PAN) is a relatively new type of network that arose due to the increase of devices such as smartphones, Wireless keyboards/printers/mice, gaming consoles, remote controls, etc.
So PAN refers to the interconnection of these personal devices within the range of an individual(range is about 10 meters). PANs are typically wireless networks that allow these devices to be interconnected with each other.
Building a PAN:
-Can do this in a wired fashion(e.g. with a single computer that connects to multiple devices using things like USB or FireWire) All devices interconnected do count as a personal area network even if there isn't any kind of network cabling.
-More commonly see a wireless PAN or WPAN(using Bluetooth, WiFi, or even Infrared, eliminating any cabling)
Advantages:
-Do not require additional space/wiring for most PANs
-Connect to numerous devices at once
-Cost-effective(almost no infrastructure required)
-Easy, reliable, & secure(usually only one that would have access to)
Disadvantages:
-Limited range(10M)
-Interferance(radio signals)
-Slow data transfer - 5EXPLAIN MAN?METROPOLITAN AREA NETWORK(MAN) is a type of network configuration that is larger than LAN & smaller than WAN. Typically may see branch offices that are relatively close together(in separate buildings in the same city or block) but still have a distance to overcome that can't be handled by ethernet. Really just a small WAN. E.g. used in Government agencies, University Campuses(may refer to as CAN(Campus Area Network) which is the same, a small WAN), Hospitals, Network of fire stations, Airports, Libraries
Technologies used to connect the two LANs usually are similar to that of a WAN environment. May use:
-Fibre Distributed Data Interface(FDDI) which may be used to transfer data in a LAN too
- Asynchronous Transfer Mode(ATM) which is commonly used for WAN connectivity, is ideal for audio & video conferencing online
- Switched Multimegabit Data Service(SMDS) which is used to transfer data over large geographical areas with reasonable bandwidth over that distance - 6MAN ADVANTAGES/DISADVANTAGES?ADVANTAGES:
-Bandwidth(potential speed for connecting links tends to be good as not as far in distance compared to a full-blown WAN, so often get a dedicated connection so bandwidth isn't shared with the public, allowing quick access to resources shared on network)
-Potential cost savings(certain implementations allow shared internet connections, so only one location has the internet connection which the other location uses too, resulting in cost savings)
DISADVANTAGES:
-Equipment can be expensive(WAN based equipment so if you want a dedicated MAN, you have to purchase everything)
-More administrative overhead(as not just managing the LAN but MAN too)
-Can become difficult to manage if it becomes too large(Can control this and look at some WAN technologies at that point)
-Most implementations require fiber optic connections(can be expensive and difficult to maintain) to cover distances that are needed. - 7EXPLAIN WMN?WIRELESS MESH NETWORK(WMN).
- Mesh networks are created using wireless access points. Unlike your home WiFi which connects to a single centralized access point, all access points are connected to the same network(so no need to specifically connect to 1 access point, then disconnect from it and reconnect to a different one if you move around). As long as you are in range with any access point, you maintain the connection to the internet.
- Access points are spread out among numerous wireless mesh nodes(typically see this configuration in very large areas where you still need wireless access(hotel, airport, etc)
- All nodes communicate with each other and share the network connection.
Mesh nodes:
-Nodes are small transmitters
-Nodes function the same as wireless routers(but all part of the same network and use the same WiFi standards, 802.11a/b/g/n) - 8WMN ADVANTAGES/DISADVANTAGES?ADVANTAGES:
-Cost savings(less setup required, fewer cables)
-Nodes are self-configuring and self-healing - just plug in & they configure themselves to access the network automatically & will try to failover to another device or attempt to restart whatever failed if something goes wrong.
-Uses technologies that are generally already in place(802.11 specifications)
DISADVANTAGES:
-Difficult to manage and maintain(devices tend to be placed in locations that are difficult to access(ceilings, behind barriers, hence difficult to physically service
- Can be expensive(as devices are added, the costs go up)
Advantages outweigh the disadvantages purely for the ease of connectivity in this scenario as not needing to physically disconnect from one access point and reconnect to another one is great - 9EXPLAIN CABLE INTERNET?CABLE INTERNET is a popular high-speed internet service.
-It's a fast & reliable technology you can use to connect a residence to the internet, using what we might consider as a standard cable TV cable.
-Often referred to as broadband technology(also known as Hybrid Fiber-Coaxial(HFC) - which is a more modern implementation as most providers use fiber, the 'hybrid' means the service provider runs fiber optic from their location to the connection point of your house.
- From that point, coaxial cable(standard cable TV cable) lines are used in the residence to run the service from something like a telephone pole into your house.
-Cable internet(service itself) uses unused channels(predefined frequency ranges that are otherwise used for tv programming)
-Requires a cable modem(focuses on frequencies carrying internet signal) & internet subscription. Coaxial cable comes from your wall & then goes into the modem(giving an incoming service & power connection). Cable modem has multiple ports so acts as a switch as well & probably wireless, giving a standard Ethernet connection to computer - 10CABLE INTERNET ADVANTAGES/DISADVANTAGES?ADVANTAGES:
-Works without a phone line
-Fast connection speed(usually fast than DSL)
-Less restricting in terms of location(if the provider uses HFC, if pure coaxial all the way from the provider, then you are typically still limited to around 3 kilometers. Most providers now using fiber so they can greatly extend the distance beyond what DSL can)
-Reliability(typically a reliable service)
DISADVANTAGES:
-Cable speeds can be influenced by: bandwidth caps, essentially a shared network so a high volume of users may give a performance degradation
-Limited availability(rural areas may have no providers for cable internet) - 11EXPLAIN BASIC CHARACTERISTICS OF DSL & PROCESS?DIGITAL SUBSCRIBER LINE(DSL INTERNET SERVICE) is a technology for delivering high bandwidth internet service over regular telephone lines(-does not compete with the telephone service so can still be on the phone when online due to it -using high transmission frequencies to separate data from voice signals. -Speeds vary depending on provider and tier, but current services should offer up to 10mbps or more for standard service)
COMPONENTS FOR DSL
Begins with your PC which would connect directly through to a DSL modem(supplied by ISP). This then connects to a DSLAM(DSL Access Multiplexer) which is a central connection point that the service has that would group all connections in one particular area. Then it would travel over an ATM network through to the service provider(where DHCP servers would be to give you an IP address) & finally giving you access to the internet. The connection between your modem & the service provider uses a service called PPPoE(point to point protocol over ethernet) which operates at the network layer to provide authentication when you initiate a connection - 12EXPLAIN ASYMMETRIC VS SYMMETRIC DSL & ADVANTAGES VS DISADVANTAGES?DSL comes in 2 varieties known as asymmetric and symmetric. Meaning there's a variance between the speed of downloads versus uploads. For most people who have this service at home, it would probably be asymmetric(ADSL) - little bandwidth going up the service provider, more going down(more downloads than uploads). Corporate networks/businesses more likely to use Symmetric(SDSL) - have an equal balance in downloads and uploads because you're transmitting as much information as you are downloading
ADVANTAGES:
-High bandwidth
-Uses existing phone lines
-Allows internet connection and phone line to be used at the same time(only for ADSL, requires a dedicated line for SDSL to do this)
-Modems are often provided by service providers
DISADVANTAGES:
-Performance can suffer the farther you are from the provider, distance limitation of about 3 miles
-Requires a landline
-Limited availability in remote areas(may not find the service as available) - 13EXPLAIN FIBER OPTIC?FIBER OPTIC is the best option these days when it comes to reliability & performance(high-speed internet access & high distance). Fiber optic lines consist of tiny strands of plastic or glass. It uses optical transmission(pulses of light as opposed to some electromagnetic current running down a copper wire). Capable of carrying more data referred to as coverage service(where services(voice, video, data) run over a single fiber cable. TV service can handle hundreds of HD channels due to bandwidth capabilities.
SPEED COMPARISON:
FIBER = 50-100Mbps(average speed), 1-10Gbps(high-end speed)
DSL= 768-1.5Mbps(average speed), 3-10Mbps(high-end speed)
CABLE= 4-6Mbps(average speed), 10-100+Mbps(high-end speed)
SATELITE= 5-10Mbps(average speed), 12-25Mbps(high-end speed) - 14FIBER OPTIC ADVANTAGES VS DISADVANTAGES?ADVANTAGES:
-Speed
-Better at carrying information over long distances(no longer have to be within 3 miles of the provider)
-Not susceptible to interference(such as Radio/Electrical because fiber optic is pulses of light)
-Lines are less prone to damage(e.g. wear and tear and heat does not really affect fiber optics)
DISADVANTAGES:
-Not available in all areas
-Requires all new infrastructure(costs absorbed by service provider but service itself for customers will be more than DSL or cable) - 15EXPLAIN DIAL-UP & SATELLITE INTERNET ACCESS. ADVANTAGES & DISADVANTAGES?DIAL-UP is an old technology, very slow by today's standards(never exceeds 56kbps). Can perform basic internet-related tasks(E-mail, browsing)
ADVANTAGES:
-Uses existing phone lines(does not require special line to be installed, only needs a modem)
-Dial-up accounts can be used anywhere there is a phone line
DISADVANTAGES:
-Slow speeds
-Ties up the phone line while the internet is in use
SATELLITE INTERNET is a wireless connection that requires three satellite dishes(1 attached to the property, one in space, one at the internet service provider). Ideal for very remote areas(e.g. may have no phone line, ships at sea)
ADVANTAGES:
-Faster than dial-up
-High bandwidth
-Does not require a phone line
-Available in remote areas
DISADVANTAGES:
-Poor latency(transmitting signals to a satellite in space so takes some time)
-Weather can affect signal strength(same with obstructions(branches/buildings)
-Bandwidth limitations(throttling)
-Can be expensive(a lot of infrastructures and service expensive) - 16EXPLAIN ISDN?INTEGRATED SERVICES DIGITAL NETWORK(ISDN) is a
-set of communication standards for digital telephone connections
-used to transmit voice and data over a digital line(uses digital packets to transmit telephone or voice information)
-originally designed to run on digital telephone systems already in use(as we can now add data to this)
-Prior to ISDN, it was not possible to use regular telephone systems for fast transportation(had no means to digitize the data and implement it as what we know as a data network)
-It's not common now but did offer higher speeds than services such as dial-up when it came out
-ISDN is a circuit-switched telephone network system(what we consider to be a regular phone network, a physical pathway, you connect one wire to another. however, packet-switched networks are all done virtually with the inter-networking equipment, with no dedicated path a packet must follow. But ISDN deals with digital communication. allowing for access to packet-switched networks(so can now use a phone network that was circuit-switched to be used as a packet-switched network) - 17ISDN TYPES & ADVANTAGES/DISADVANTAGES?ISDN has largely been replaced by broadband internet connections in recent years, may still find few specific configurations where it's used as a legacy implementation for a particular purpose. You needed specific hardware to translate packet-switched network data into a circuit-switched network. ISDN bridge handled all the translation, needing to be on both sides(if connecting branch offices)
2 main types of ISDN connections:
-Basic Rate Interface(BRI/2B+D) = a lower tier of service, providing only basic needs, lower cost - 2 channels(each 64Kbps), B channel has bandwidth, D focused on timing format of communication.
-Primary Rate Interface(PRI/T1-PRI(23B+D, 1.5Mbps)/E1-PRI(30B+D, 2Mbps) = better connection, more reliable, faster speeds
ADVANTAGES:
-Multiple digital channels available to improve transfer rates
-Consistent transfer rates
-Governed by a worldwide set of standards(know what you're going to get)
-Competitively Priced to other options at the time
DISADVANTAGES:
-Costly compared to other telephone systems(if this is all you need)
-Requires specialized digital devices - 18EXPLAIN LINE OF SIGHT(LOS)?LINE OF SIGHT(LOS) is a feature of networking. Line of sight is the path between two antennas. It's important to consider any obstruction when designing an outdoor wireless network. Fresnel zone refers to the area in between points A & B. The area may have electromagnetic signals still experiencing some kind of interference
Options for LOS:
- LOS, Complete line of sight, no obstacles reside between two antennas(transmit signal clearly), nothing is getting into the fresnel zone, pretty good communication.
- Near Line of Sight(nLOS), may include partial obstructions between two antennas(e.g. treetops)
- Non Line of Sight(NLOS), full obstructions may exist between the two antennas(in the fresnel zone). likely you encounter a lot of connectivity problems.
This type of communication is not common, only a good feasible option if you have a clear line of sight for connectivity needs - 19EXPLAIN CELLULAR NETWORKS?Cellular networks are the networks over which mobile phones can operate(referred to as mobile networks).
Term cellular persists because of the way it's laid out as the network is split into cells. Each cell has an antenna, the cell is the area covered by that particular tower(then another tower just overlaps it a bit to cover a large geographic area as efficiently as possible). Neighboring cells operate at different frequencies, but an access method is known as FDMA(Frequency division multiple access) allows devices to select the strongest frequency to communicate better - 20EXPLAIN ACCESS METHODS CDMA & TDMA?Code Division Multiple Access(CDMA) is used to allow several users to send data over the same frequency without interfering with each other on a cellular network, as:
-Each transmitter is assigned a code
-The signal is spread over a range of frequencies using a pseudorandom pattern
-The signal for each user is modulated by their unique code.
So the code controls the signal of your device and is separate from yours and every other one, being able to distinguish my signal from yours so we can all access the same network at the same time.
Time Division Multiple Access(TDMA) is a -channel access method used for channel sharing without interference.
-Allowing multiple stations to use & share the same transmission channel at the same time(cause signals are divided up into different time slots & all have to be synchronized. But synchronization & timing of signals presented a challenge as users moved(mobile users so the distance changed, resulting in signal arriving at a different time, so difficult to manage)
So TDMA was largely in 2G mobile networks & has largely been superseded by CDMA
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- Learning Technology Specialist CompTIA A+ (Core 1) FlashCards sobre Module 11, criado por Chantelle Knight em 09-09-2021.
- Criado por
- Chantelle Knight
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