The Bits and Bytes of Computer Networking: Week 1 Flashcards
What is the TCP/IP Five-Layer Network Model
Physical Layer > Data Link > Network > Transport > Application
What is the 5th layer (bottom) of the TCP/IP Network Model and what does it achieve?
Physical Layer - Represents the physical devices that interconnect computers, includes specifications for networking cables and how signals are sent.
What is the 4th layer of the TCP/IP Network Model and what does it achieve?
Data Link Layer - Responsible for defining a common way of interpreting these signals so network devices can communicate.
Lots of protocols exist on this layer, the most common being ethernet. The ethernet standards also define a protocol responsible for getting data to nodes on the same network or link.
What is the 3rd layer of the TCP/IP Network Model and what does it achieve?
Network(Internet) Layer - Allows different networks to communicate with each other through routers.
The network layer is responsible for getting data delivered across a collection of Networks.
IP is the heart of the internet & most smaller networks, it resides in this layer.
What is the 2nd layer of the TCP/IP Network Model and what does it achieve?
Transport Layer - Sorts out which client and server programs are supposed to get data. Ensures that data gets to the right place. (TCP)
What is the 1st layer (top) of the TCP/IP Network Model and what does it achieve?
Application - What the user interacts with. The application layer is used by end-user software such as web browsers and email clients. It provides protocols that allow software to send and receive information and present meaningful data to users.
What is Internetwork?
A collection of networks connected together through routers. The most famous of these being the internet.
What do cables do in networking?
Connect different devices to each other, allowing data to be transmitted over them.
What are the most common copper-twisted pair cables used in networking?
Cat5 - Oldest iteration.
Cat5e - Replaced Cat5 due to having cross talk. Cat5e eliminated it.
Cat6 - Strict specifications to avoid crosstalk. Can transfer data faster and more reliably, but because of internal arrangement, a shorter distance at max speeds.
What is crosstalk?
When an electrical pule on one wire is accidentally detected on another wire
What are Fiber Cables?
Contain individual optical fibers,. which are tiny tubes made out of glass about the width of a human hair. Uses pulses of light instead of electricity.
Can transport data quicker, and at higher distances without data loss than copper wires can.
What is a hub?
A physical layer device that allows for connections from many computers at once.
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.
What is a Network Switch?
Data link devices instead of physical like a hub. The switch can inspect what’s being sent with the Ethernet protocol. It determines which system it’s instead for and only sends it to that one system. Reduces/completely eliminates collision on the network which increases higher overall throughput.
Hubs + switches are the primary devices used to connect computers on a single network, usually referred to as a LAN. (Local Area Network)
What is a router?
A device that knows how to forward data between independent networks.
Routers operate on the network (3rd) layer.. Routers inspect IP data to determine where to send things.
A core router is used by ISP’s which deals with many connections and where to send the traffic they’re receiving.
Internet
^
ISP
^
PC > Router < Laptop
