Karteikarten
Module 6
Karten in diesem Stapel (21)
- 1DEFINE HUBS?HUBS & BRIDGES WON'T BE ENCOUNTERED IN NEWER NETWORKS, BEING LOWER-LEVEL DEVICES WITH RESPECT TO THE OSI MODEL. PRICE OF HARDWARE HAS DROPPED IN HIGHER LEVEL DEVICES(switches, routers) REPLACING THE USE OF HUBS AND BRIDGES.
HUB operates at layer 1 OF OSI MODEL(physical layer) - meaning no programming, no intelligence of any kind built into a hub. Still, a device that can connect several computers together but any signal that is received on a hub is copied to all other ports(every system on that hub will hear the traffic, resulting in extra noise and interrupting those that aren't involved in the communication as they have to see and examine the packet still). Worse the higher amount of computers you get.
2 types of Hubs:
ACTIVE - includes ability to regenerate and boost the signal(repeating) before sending it to other ports if big distance.
ACTIVE HUBS can be used to extend the length of a network due to this.
PASSIVE - simply gives a physical connection point for computers, not responsible for amplifying or regenerating signal, cannot be used to extend the length of a network - 2DEFINE BRIDGES?BRIDGES OPERATE AT LAYER 2 OF THE OSI MODEL(aware of addresses but the only address operating at Layer 2 is the physical address(AKA MAC address)). KEY FUNCTIONS OF A BRIDGE:
JOIN SIMILAR TOPOLOGIES TOGETHER(so if you have one ethernet network over there and another somewhere else, you could connect them together), ALLOWING YOU TO DIVIDE ANY NETWORK THAT YOU MAY ALREADY HAVE INTO SMALLER SEGMENTS(collision domains(when using hubs, everyone may transmit at the same time, causing collisions if packets end up on the same wire at the same time, destroying them and resulting in retransmitting). CAN ALSO ISOLATE NETWORK TRAFFIC, allowing only certain packets to cross.
CONSIDERATIONS USING BRIDGES:
- BRIDGES FORWARD BROADCAST PACKETS(broadcast address to all computers, increasing amount of noise unlike routers which don't forward broadcast packets).
BRIDGES CANNOT PERFORM ANY INTELLIGENT PATH SELECTION(path between sender and destination will always be the same but as the network grows, there may be more than one route but the bridge will not be aware of which route to use) - 3DEFINE SWITCHES?SWITCHES ARE INTERCONNECTION DEVICES LIKE A HUB WHERE THEIR JOB IS TO CONNECT MULTIPLE SYSTEMS TOGETHER, BUT A SWITCH OPERATES AT LAYER 2 OF THE OSI MODEL(can examine layer 2 header information from incoming packets, based on this they forward the packets to a specific port(improving performance and reduces overhead)). USES MAC ADDRESSED TO DETERMINE WHERE TO TRANSMIT DATA(has some intelligence, the switch recognizes mac address for physical port), PROVIDING CENTRALISED CONNECTIVITY(similar to a hub but smarter).
LOOK LIKE A HUB(which it essentially overtook) WITH MULTIPORT DEVICES(e.g. 8 ports), DIFFERENT TO A BRIDGE AS THEY ARE NOT CONCERNED WITH CONNECTING INDIVIDUAL COMPUTERS TOGETHER BUT CONNECTING NETWORK SEGMENTS(to isolate traffic of segment one from two, only having 2 interfaces) - 4ADVANTAGES AND DISADVANTAGES OF SWITCHES?ADVANTAGES:
- INCREASES AVAILABLE NETWORK BANDWIDTH(fewer packets flying around with the ability to filter traffic based on MAC address)
- INCREASES NETWORK PERFORMANCE(helps regulate the flow of traffic, reduce collisions)
- INCREASES SECURITY(as aware of addresses so hard for hackers to pick up on traffic)
DISADVANTAGES:
- COST(more expensive than a hub)
- MORE DIFFICULT TO TROUBLESHOOT(because if any 2 systems can't seem to communicate, you have to identify which ports they are on and if someone maybe moved them to a different port/location, it can be difficult to know where they went)
- DEVICES CAN BE SPOOFED(as there is intelligence, meaning there's programming that can be spoofed, so an attacker can get into the switch and reconfigure it so packets supposed to be sent are redirected)
- HENCE PROPER DESIGN AND CONFIGURATION IS NEEDED(to ensure this doesn't happen) - 52 CATEGORIES OF SWITCHES?MANAGED:
OFTEN REFERRED TO AS AN INTELLIGENT SWITCH - has its own IP address and configuration interface, and typically you connect to it using a special software application or a dedicated management port. Allowing you to get in there and configure it.
UNMANAGED:
A DEVICE THAT CAN PERFORM SWITCHING WITHOUT ANY USER INTERVENTION, ESSENTIALLY PLUG AND PLAY - cannot control the functions of this type of switch due to this which is limiting. Can often be more cost-effective for smaller deployments because often cheaper. ULTIMATELY SWITCHES ARE MUCH SMARTER THAN HUBS AND WILL DRAMATICALLY IMPROVE THE PERFORMANCE OF YOUR NETWORK. MANAGES VS UNMANGES IS UP TO YOU DEPENDING ON THE NEEDS OF YOUR ENVIRONMENT - 6DEFINE ROUTERS?ROUTERS = INTELLIGENT DEVICES USED TO DETERMINE THE BEST PATH FOR TRANSMITTING DATA BETWEEN NETWORKS. ROUTING TABLES ARE USED TO STORE NETWORK ADDRESS(intelligent as someone programs these tables initially, & the network addressed represents the routes available to that router. routers can exchange info about the routes they have been programmed with, literally becoming smarter). ROUTERS CAN TRANSMIT DATA ACROSS MULTIPLE NETWORKS(e.g. divide a very large network into several smaller IP subnets(different networks) which connect everyone in an efficient manner)
ROUTERS OPERATE AT LAYER 3 OF THE OSI MODEL(network layer), HENCE MORE CONCERNED WITH NETWORKS THAN INDIVIDUAL COMPUTERS. SUPPORT VARIOUS NETWORK TYPES, LAN, WAN(and in terms of physical cabling it could be copper or fiber)(as long as it runs on TCP/IP, then routers can route the traffic appropriately)
ROUTERS ARE THE DEVICE REQUIRED FOR INTERCONNECTING LANs ACROSS A WAN OR ACROSS ANY OTHER CONFIGURATION. AS SOON AS YOU HAVE TWO SEPERATE NETWORKS, REGARDLESS OF WHERE THEY ARE, YOU MUST HAVE A ROUTER BETWEEN THEM TO COMMUNICATE - 7KEY FUNCTIONS OF ROUTERS?KEY FUNCTIONS:
CONNECT MULTIPLE NETWORKS TOGETHER UNLIKE A SWITCH OR A HUB, ROUTERS DO NOT FORWARD BROADCAST PACKETS(unlike bridges, routers create a boundary so broadcast domains are broken up).
ROUTERS DETERMINE THE BEST ROUTE TO THE DESTINATION BASED ON DISTANCE(how many routers will be crossed) AND CONGESTION(how much traffic is on a given route) - 8DEFINE ACCESS POINTS, REPEATERS & EXTENDERS?ACCESS POINTS - ANY POINT THAT ENABLES USERS ACCESS TO A NETWORK, COMMONLY USED WHEN REFERENCING A WIRELESS ACCESS POINT(an access point that enables users to connect over wireless)(can have as many access points as long as they connect to the same network).
ACCESS POINTS HAVE REPEATERS AND EXTENDERS THAT OPERATE AT THE PHYSICAL LAYER(layer 1) OF THE OSI MODEL. ITS DESIGNED TO IMPROVE SIGNAL RANGE AND STRENGTH BY AMPLIFYING ANY SIGNAL THEY RECEIVE(repeater picks up the signal and passes it on, repeats it to extend range). THIS HELPS IMPROVE OVERALL COVERAGE TOO. REPEATERS CAN OPERATE WIRELESSLY OR WITH A WIRE(wire repeater to original router). LIKELY SEE IN A HOTEL/AIRPORT - 9NETWORK CONTROLLERS?NETWORK INTERFACE CARD(NIC) - IS HOW YOU CONNECT YOUR PC's TO A SWITCH(via a NIC). NICs CAN BE WIRED(physical port on the back of the interface where you connect standard ethernet cable) OR WIRELESS(antenna coming out of the back)
ANY DEVICE THAT WANTS TO NETWORK REQUIRES AT LEAST ONE INTERFACE(NIC). CAN EITHER BE HARDWIRED(soldered onto the motherboard, if it broke and you had an open slot on the motherboard, you could install a modular uni and still continue networking) OR MODULAR(modular interfaces enable easy replacement as it's just a card you can insert into motherboard slot) - 10NIC PROPERTIES?NIC PROPERTIES:
- SPEED(megabits/gigabits per second value, usually automatically detects settings and adjusts accordingly) AND DUPLEX(refers to the direction of traffic, can go in both directions(simplex is the opposite(radio)) - can be configured but will have default values in places such as full-duplex(both systems can send and receive at the same time, faster), half-duplex(have to take turns communicating, one has to listen while the other sends(taking turns in a phone call to speak)) and auto-negotiate setting.
- WAKE ON LAN - a feature that the system administrators of larger networks might take advantage of when upgrading or configuring to all of the computers at more or less the same time. Typically done late at night. If the device itself and the computer at the BIOS level support WAKE ON LAN, then an administrator can send a packet known as a wake-up packet(as soon as it hits the adapter, it instructs the system to come out of sleep and or turn on that that they can be managed/receive the update or whatever configuration is coming down from the network administrator). - 11DEFINE MODEMS & DIAL UP MODEMS?MODEMS ARE HARDWARE DEVICES USED TO CONNECT TO A REMOTE NETWORK OR THE INTERNET. TERM IS A CONTRACTION OF 'MODULATE' AND 'DEMODULATE' AND THAT REFERRED TO THE PROCESS OF CONVERTING ANALOG SIGNALS OR ELECTRICAL SIGNALS INTO DIGITAL SIGNALS SO YOU CAN SEND AND RECEIVE DATA OVER THE TELEPHONE LINE AND CABLE LINE.
USE TO NEED DIAL-UP MODEMS IN THE OLD DAYS TO ESTABLISH AN INTERNET CONNECTION THROUGH TO OUR INTERNET SERVICE PROVIDER USING THE TELEPHONE LINE. MODEMS DIAL INTO THE INTERNET SERVICE PROVIDER(ISP) TO ESTABLISH AN INTERNET CONNECTION, COULD NOT USE YOUR HOME PHONE OR RECEIVE A CALL WHILE YOU HAD THIS CONNECTION THOUGH. WAS PAINFULLY SLOW(maximum of 56 kilobits per second) - 12DEFINE DSL AND CABLE MODEMS?DIGITAL SUBSCRIBER LINE(DSL) WAS A POPULAR METHOD FOR TRANSFERRING DIGITAL SIGNALS OVER STANDARD TELEPHONE LINES(don't need to modulate and demodulate but some people still call it a DSL modem as it performs the same function). DSL MODEMS ARE USED TO CONNECT TO A DSL ISP(has superseded the dial-up modems with significantly faster speeds). CERTAIN MODELS HAVE BUILT-IN Wi-Fi CAPABILITIES/CAN USE PHONE AT SAME TIME TOO(as it uses different frequencies)
CABLE MODEMS ARE HARDWARE DEVICES THAT USE COAX CABLE TV LINES TO PROVIDE HIGH-SPEED INTERNET ACCESS. ALWAYS ON CONNECTION(as even original DSL had to establish a connection through ISP before going online). OFFERS MUCH FASTER DATA TRANSFER RATES COMPARED TO ORIGINAL MODEMS - 13DEFINE STRUCTURED CABLING, PATCH PANELS?STRUCTURED CABLING IS JUST A FANCY TERM FOR BEING NEAT & ORGANISED - apply some organization for everything, you bundle the cables together, tie them with plastic ties or grommets, maybe run them through cable troughs, maybe even use heat shrink(plastic wrap that tightens up). This gives SAFETY & AESTHETICS(can label cables, ties/clips, and even use floor covers if a wire does have to cross the floor).
The data port in the wall that wall wires are connected to is on one end, the PATCH PANEL is on the other end where it comes out. A technician hard wires those wires to the backside of a patch panel, labeling it so you know where the other end is. SO A PATCH PANEL IS MOUNTED HARDWARE ASSEMBLY CONTAINING MULTIPLE PORTS - switches are below each port of the patch panel, all wires from the room connect to this and everyone is connected. USED IN LAN TO HOUSE MULTIPLE CABLE CONNECTIONS, PORTS USED TO CONNECT/MANAGE LAN CABLES(both incoming & outgoing) - 14TYPES OF PATCH PANELS?TYPES OF PATCH PANELS:
THESE ARE BASED ON THE NUMBER OF PORTS THEY CONTAIN, COME IN VARIETIES OF - 12 PORT, 24 PORT, 48 PORT.
CAN ALSO CARRY VARIOUS CABLE SPECIFICATIONS, CAT CABLES - Cat5E, Cat6, Cat6A, Cat7(stands for the category, with number and letters at the end, are different transmission specifications for the call standard ethernet networks. some are faster or have different characteristics etc, but all use the same physical connector). ALL ARE CENTRALISED AT THE PATCH PANEL, WHICH CONNECTS TO SWITCHES, ALLOWING EVERYONE TO BE CONNECTED. PATCH PANEL is nothing more than neat storage for extension cords in a single place to centrally connect all the other actual networking devices. - 15DEFINE NETWORK RACKS?NETWORK RACKS ARE FOR LARGER ENVIRONMENTS - THESE ARE METAL FRAME CHASSIS THAT CAN STACK AND CATEGORIZE DIFFERENT NETWORKING COMPONENTS INCLUDING THE PATCH PANELS, SWITCHES, AND ROUTERS. MAY HAVE THOUSAND OF DATA PORTS WHICH ALL NEED TO BE CONNECTED TO A CENTRAL LOCATION FOR OPTIMAL ORGANISATION. RACKS GIVE YOU THE EXTRA SPACE. PATCH CORDS CAN AGAIN BE USED TO CONNECT A PATCH PANEL TO A NETWORK SWITCH(as the cord in the back of the patch panel is simply representative of the other end of your wall jack in your office.
- 16DEFINE PoE?POWER over ETHERNET(PoE) - A TECHNOLOGY USED FOR WIRED ETHERNET LANs THAT ENABLES ELECTRICAL CURRENT TO BE CARRIED OVER DATA CABLES( as an alternative to power cords). POWER over ETHERNET DELIVERS BOTH THE DATA AND THE POWER. HAVE TO HAVE A DEVICE CAPABLE OF ACCEPTING THIS(specifically designed for PoE, if so only need to run the data cable to that device, don't need a second power cable. COMMONLY USED WHEN IMPLEMENTING WIRELESS ACCESS POINTS IN REMOTE LOCATIONS THAT DO NOT HAVE POWER OUTLETS(for example, ceilings).
IEEE 802.3bt SPECIFICATION WAS REFINED AS THE NEXT GENERATION PoE - POWERFUL ENOUT TO SUPPOR A VARIETY OF DEVICES INCLUDING KIOSKS, TERMINALS, LED LIGHTING, SECURITY CARD READERS, SECURITY CAMERAS. MAKES THINGS SIMPLER BECAUSE YOU DON'T HAVE TO RUN POWER, SO YOU CAN RUN THAT SINGLE DATA CABLE TO THE DEVICE AND IT RECIVED BOTH ITS DATA AND POWER OVER THAT SAME CABLE. - 17DEFINE ETHERNET OVER POWER AND CONFIGURATION?OPPOSITE OF PoE, A TECHNOLOGY USED TO TRANSMIT DATA USING COMMON ELECTRICAL WIRING(using the power circuits that are in your house as wiring for data signals, avoids installing additional cables). IN ORDER TO FUNCTION PROPERLY, AN ELECTRICAL OUTLET AND AN ETHERNET OVER POWER ADAPTERS ARE REQUIRED(both devices must be on the same electrical circuit).
IDEAL WHEN IT IS NOT POSSIBLE TO RUN CABLES FOR A NETWORK CONNECT AND IF Wi-Fi CANNOT REACH THAT AREA - YOU PLUG THIS DEVICE INTO THE POWER AND IT HAS AN ETHERNET CONNECTION NEAR IT, THEN YOU PLUG IN ANOTHER ONE AT THE END WHERE THE DEVICE IS WHERE IT NEEDS TO CONNECT, USING THE EXISTING POWER CABLES THAT RUN BETWEEN THE DEVICES TO CARRY ETHERNET SIGNAL(considered an alternative to Wi-FI.
CONFIGURING:
SIMPLE SET UP, PLUG-IN DEVICES, AND NEGOTIATE THE CONNECTION(e.g. press the button on the side of the device). - 18DEFINE FIREWALLS?FIREWALLS CAN BE BOTH HARDWARE AND SOFTWARE BASED, ULTIMATELY USED TO ALLOW OR DENY A CONNECTION BASED ON A SET OF RULES, CAN IMPLEMENT PACKET FILTERS WHICH USE RULES BASED ON IP ADDRESSES AND PORTS, THERE ARE TYPES KNOWN AS STATEFUL FILTERS WHICH MEANS A FILTERS BEING IMPLEMENTED AND IT MAINTAINS THE ENTIRE SESSION STATE INFORMATION(keeps track of everything that's happened between the two endpoints for the entire duration of the communication). FIREWALLS ALSO HELP TO PROTECT AGAINST OUTSIDE THREATS SUCH AS HACKERS.
- 19DEFINE HARDWARE FIREWALLS?HARDWARE FIREWALLS - TYPICALLY A SPECIALIZED NETWORK APPLIANCE THAT IS RACK-MOUNTED OR JUST A SMALLER BOX TYPE UNIT. PLACED BETWEEN THE NETWORK AND THE UNTRUSTED NETWOR(on one side is your internal LAN and the other side is the internet). THEN CONFIGURE PORT AND IP ADDRESS RULES(what you feel is acceptable traffic - e.g. if you have a web server then you need to make sure port 80 for HTTP is allowed through the firewall. but if you have a database server behind the firewall, you want to make sure that the protocols for the database server would not be allowed through the firewall to help protect it). HARDWARE FIREWALLS CAN ACT IN VARIOUS ROLES DEPENDING ON THE FUNCTIONALITY OF THE DEVICE, ACTING AS A CONTENT FILTER(allow or deny based on the content), VPN CONCENTRATOR(meaning that's the single point where all of your outside users access your network through a VPN), AND IN SOME CASES A HONEYPOT(something that appears to be of interest to an attacker but really is a trap to catch them in the act).
- 20DEFINE SOFTWARE FIREWALLS AND CONTENT FILTER?SOFTWARE FIREWALLS ARE USUALLY RUNNING ON A HOST AS AN APPLICATION. TYPICALLY FOUND IN SMALL OFFICE OR HOME COMPUTERS, USUALLY, ONLY PORT BASED(simply means this port is allowed and this port is not allowed). CAN CONTROL INTERNET ACCESS PER APPLICATION(certain ones you may not want on the internet). IF OPERATING SYSTEM BECOMES COMPROMISED, SO DOES THE FIREWALL(so important to keep it current, up to date so the firewall remains running)
CONTENT FILTERS CAN BE PART OF A FIREWALL OR A SEPARATE DEVICE. THEY CAN ANALYZE PACKETS(examine the content) AND ALLOW OR DENY REQUESTS BASED ON RULES YOU SET UP. COMMON FILTERS INCLUDE EXECUTABLES, EMAILS OR WEBSITES(so you configure these with respect to what is acceptable content or not) - 21CLOUD-BASED NETWORK CONTROLLERSTHE NETWORK CONTROLLER GATHERS INFORMATION FROM ALL WIRELESS ACCESS POINTS ON-PREMISE IN A PROCESS KNOWN AS WIRELESS BACKHAUL(communication is tunneled back to the controller, including info such as control-plane(represents the instructions/means to manage the traffic) & data-plane(the actual traffic itself). SO ACCESS POINTS REPORT THIS INFO BACK TO THE CONTROLLER, WHICH GATHERS IT UP & GIVES A BETTER PICTURE OF WHAT THE TRAFFIC LOOKS LIKE, ALLOWING YOU TO THEN CONFIGURE ALL ACCESS POINTS USING THE NETWORK CONTROLLER.
A CLOUD-BASED NETWORK CONTROLLER IS A SERVICE THAT YOU CAN SUBSCRIBE TO. ALLOWING A BIGGER AREA SUCH AS MULTIPLE CAMPUSES TO REPORT ALL THEIR TRAFFIC INFO BACK TO THIS LOCATION IN THE CLOUD. AS THEY ALL CONNECT TO A VIRTUAL CONTROLLER LOCATED IN THE PUBLIC CLOUD. THEN ABLE TO BE CONFIGURED FROM THE CLOUD-BASED LOCATION WHERE THE ADMINISTRATOR CAN ACCESS THAT INFO FROM ANYWHERE & RECONFIGURE IT. CONVENIENT METHOD WHERE NO MANUAL CONFIGURATION IS DONE & THE NETWORK CONTROLLER APPLICATION DOES NOT NEED TO BE INSTALLED, MAINTAINED, OR UPDATED AS CLOUD PROVIDER DOES THIS.
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- Learning Technology Specialist CompTIA A+ (Core 1) Karteikarten am Module 6, erstellt von Chantelle Knight am 27/08/2021.
- Erstellt von
- Chantelle Knight
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