The Physical Layer (TCP/IP) Flashcards
The physical layer (1st layer of the TCP/IP 5 Layer Network Model)
What are the two categories for cables?
Copper and Fiber-optic cables
How is data communicated through copper cables?
Different voltages represent different binary bits
What is the physical makeup of Copper cables?
Copper cables have strands of copper twisted inside them
What are the most common forms of copper twisted-pair cables used in networking?
Cat5, Cat5e, and Cat6
What is Crosstalk with respect to cables?
Crosstalk is when an electrical pulse on one wire is accidently detected on another wire
What is the physical makeup of Fiber-optic cables?
Fiber cables contain individual optic cables, which are tiny tubes made of glass about the width of a human hair
How is data communicated through fiber cables?
Pulses of light represent binary values
What is a network Hub?
A physical layer device that allows for connections from many computers at once
How do network Hubs operate?
All the devices connected to a hub will end up talking to all other devices at the same time. It’s up to each system connected to the hub to determine if the incoming data was meant for them, or to ignore it if it isn’t
What is a Collision Domain?
A network segment where only one device can communicate at a time. If multiple systems try sending data at the same time, the electrical pulses sent across the cable can interfere with each other. This causes these systems to have to wait for a quiet period before they try sending their data again
What is a network Switch?
A data link (layer 2) device that allows for connections from many computers at once
How do network Switches operate?
Switches can inspect the Ethernet protocol data being sent around a network, determine which system its for and sent it only to that system
What is a single network referred to as?
Local Area Network (LAN)
What is a network Router?
A Layer 3 device that knows how to forward data between independent networks
How do network Switches operate?
A Router can inspect IP data to determine where to send it to. Routers store internal tables containing information about how to route traffic between lots of different networks all over the world
What are Core ISP Routers?
When your home/office Router connects to an ISP, the data reaches a Core ISP Router, which is vastly more sophisticated and figures out where to send your data
What is BGP (Border Gateway Protocol)?
A protocol routers use to share data with each other, letting them learn the most optimal paths to forward traffic
Why are Nodes called Nodes?
Nodes can be either a Server or a Client, and can alternate between the two although they usually act primarily as one or the other
What is Modulation?
A way of varying the voltage of a charge moving across a cable
What is Line Coding?
When devices on either end of a physical link understand that an electrical in a certain state is a zero, and in another state a one
What is Duplex Communication?
The concept that info can flow in both directions across a cable
What is Simplex Communication?
The concept that info flows in only one direction across a cable
What is Full Duplex Communication?
The concept that info can flow in both directions across a cable at the same time
What is Half Duplex Communication?
The concept that info can flow in both directions across a cable, but once at a time
What is the most common networking port/plug?
Registered Jack 45 (RJ45)
Describe what the lights on a RJ45 plug mean
There are two LEDS, a Link LED and a Activity LED. The Link LED blinks when two devices are connected and powered on, while the Activity LED blinks when data is being sent across the cable.
What is a Patch Panel? Where are they in a house?
A Patch Panel is a device containing many network ports, and are usually in a wall
