Unit 6 - Networks and the Internet Flashcards
What does ARPA stand for?
Advanced Research Projects Agency. U.S. Government research
What is a LAN?
A local area network where all computers within a physical location are connected to.
What does UTP stand for?
Unshielded Twisted Pair. It is a cable for networking computers together and has an RJ-45 connector.
What is a HUB?
The simplest of network devices. It takes the signal from one cable and splits it out to several others. With four out-signals it would be a four port hub. Sending information back is sending it through the uplink connection.
What is a switch?
Similar to a hub but has basic filtering of data. Switches can prevent e.g. a broadcast storm, making sure data sent to the broadcast address is only sent to the ones that can receive it.
What is a router?
An intelligent networking device. It can filter data, block it, and ensures data is only sent to the correct destination.
What is the most common network topology today?
Star topology.
What is a ring topology?
A ring of devices connected together. Each computer passes all signals along, and it is not fault-tolerant.
What is a mesh topology?
Every node is connected to every other node. Very fault-tolerant but requires lots of cabling.
What is a star topology?
A central hub or switch that sends traffic to all outer node. It is fault-tolerant unless the central hub fails.
What is a bus topology?
All computers are connected to the bus, and if a connection is broken the entire network fails. Not fault tolerant, but is used in some network backbones.
What is a hybrid network topolgy?
A topology that combines multiple topologies.
What are characters of a wired network?
Device physically limited by a cable
Relatively easy to troubleshoot
Fast data speeds
Very secure
What are the characteristics of a wireless network?
Device can move freely within range
Can be difficult to troubleshoot
Medium data speeds
Easy to intercept (hack) the signal)
Only requires a wireless access point (and wireless support on the device)
What is the IEEE?
Institute of Electrical and Electronics Engineers. An organization providing technical standardization for wireless networks among other things.
What is IEE 802.11?
The standard for WiFi. Going up to 802.11ac which allows up to 3Gbps speeds over 2.4 and 5GHz frequencies.
How many layers are in the OSI model?
Seven
What is OSI layer 1?
P – Physical Layer is the physical devices and electrical signals. Hubs, switches, routers, cabling.
Wireless frequencies, bit rate control
What is OSI layer 2?
D – Data Link Layer responsible for formatting electrical signals into data, local network error checking including collisions (collision detection).
MAC (Medium Access Control), Logical Link Control (LLC), PPP (Point-to-Point Protocol)
What is OSI layer 3?
N – Network Layer responsible for routing data via IP-address. Data is organized into packets.
What is OSI layer 4?
T – Transport Layer sends and receives data using protocols and settings.
TCP/UDP are in layer 4. TLS is partly in Layer 4, partly in layer 6.
What is OSI layer 5?
S – Session Layer maintaining and communication for sessions (e.g. ports)
DNS, name resolution protocols, user logon, session management.
What is OSI layer 6?
P – Presentation Layer containing data formatting (e.g. Unicode) and encryption.
What is OSI layer 7?
A – Application Layer containing user interface and applications.
