ISC S2 Flashcards
(58 cards)
Modems
-a device that bring the internet into a home or office ( receives analog signals from the internet provider and translates those signals into digital signals)
Routers
-manage network traffic by connecting devices to form a network
-act as a link between modem and switches ( computers)
-each router has public IP address
Switches
-similar with routers but does not has IP address, but does not have many advanced functions as router
-network switch can turn one network jack into several network jacks
Gateways
A gateway is a computer/device that acts as an intermediary between different networks.
Transforms data from One Protocol Into Another so that information can flow between networks.
A protocol is a rule, or set of rules, that governs the way in which information is transmitted.
edge-enable device
Allows computing, storage, and networking functions to be closer to the devices where the data or system request originates, rather than a distant central location.
The benefit is that distributed computing power is faster network response times.
Servers
Physical/Virtual machines that Coordinate computers, programs, and networks together.
Most networks use a client/server model in which the client sends a request to the server, and it provides a response or executes some action
Firewalls
-software applications or hardware devices that protect a person’s company’s network traffic by filtering it through security protocols with predefined rules
Network address translation firewalls
-Assign an internal network address to specific, approved external sources so that those sources are approved to be inside the firewall.
Topology
-Network infrastructure physical layout
-its a physical layout of equipment, or nodes in a network
Bus Topology
layout is either in a linear/tree form, with nodes connected to a single line/cable.
Data can be transmitted by any node on the system at the same time which can cause signal interference.信号干扰
To avoid, cables must be Terminated/Properly finished, at each end so signal is managed
Disadvantage of this is if the central line is compromised, the entire network is offline.
Mesh topology
-there are numerous connections between nodes
-While the number of pathways allows high levels of traffic and promotes network stability if a node is damaged, it can be costly to implement and maintain over the network’s lifespan
Ring Topology
-unidirectional ring path: move in one direction
-muti-directional paths that allow two way data transmission
-when data is transferred it must go through every other device between the source and the destination
-advantage: data transmission collision is minimized or eliminated
Star Topology
-There can be multiple hubs so that if one fails, only the nodes connected to that hub will stop functioning
-while the hub is a single point of failure, this structure makes it easy to identify damaged cables
The open system interconnection ( OSI) model - 7 layers
-explains how these protocols work, and how networking devices communicate with each other
- 7 layers ( from 7 to 1): application -> presentation-> session -> transport -> network -> data link-> physical
Layer 7 : application
-serves as the interface 界面between application that a person uses and the network protocol needed to transmit a message
-common protocols used in this layer: http, FTP, simple mail transfer protocol ( SMTP), electronic data interchange ( EDI)
Layer 6: presentation
- device using the OSI model can interpret such as standard format for video, images and web page
-Encryption 加密 occurs at this layer - ie: JPEG, MPEG, ASCII
Layer 5: Session ( think chat-room)
-sessions allow networking devices to have dialogue with each other
-ie: SQL, remote procedure call ( RPC), network file system ( NFS)
Layer 4: transport
-this layer supports and controls the communication connections between devices. it involves setting the rules for how devices are referenced, the amount of data can be transmitted, validating the data’s integrity, and determining whether data has been lost
-ie: TCP, UDP
Layer 3: Network
-adds routing and address headers/footers to the data, such as source and destination IP addresses so that the message reaches to correct devices
-it detects errors
-ie: IP, internet protocol security ( IPSec), Network address translation ( NAT), internet group management protocol ( IGMP)
Layer 2: data link
-data packets are formatted for transmissions. It is determined by the hardware and networking technology, which is Ethernet
-Media access control ( MAC) addresses
-Integrated Services Digital Network (ISDN), Point-to-Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP), Address Resolution Protocol (ARP).
Layer 1: physical
-converts the message sent form the data link layer into bits
-ie: high speed serial interface ( HSSI), synchronous optical networking
Local -Area Network ( LAN)
-provide access to a limited geographic area such as home or single location office
Wide-area network ( WAN)
-hardware- based
- good example is internet
-provide access to a larger geographic area such as cities, regions, or countries
Software-defined WAN ( SD-WAN)
-software-defined, dynamic
-in WAN the control and management of the network is integrated into hardware, but in SD-WAN control and management are separated from the hardware and included in software
