Physical Layer
The most common forms of copper twisted pair cables used in networking.
Cat5, Cat5e and Cat 6 cables.
These cables allow for duplex communication (full-duplex). Data flows in both directions.
The way networking cables ensure that duplex communication is possible is by reserving one or two pairs for communicating in one direction.
They then use the other one or two pairs for communicating in the other direction.
The protocol data unit that is used in this layer.
What are ethernet frames?
A highly structured collection of information presented in a specific order.
A device that knows how to forward data between independent networks.
What is a router?
The protocols at this layer.
What are TCP/UDP?
TCP - Transmission Control Protocol:
UDP - User Datagram Protocol:
One of the applications that allows you to search the internet, operates at the application layer.
What is a web browser?
A device that allows for connections from many computers at once.
What is a hub?
A data link layer device.
What is a switch?
A switch can inspect the contents of the ethernet protocol data being sent around the network. Determine which system the data is intended for and then only send that data to that one system.
This reduces or even completely eliminates the size of collision domains on the network.
If you guess that this will lead to fewer re-transmissions and
higher overall throughput, you're right.
The protocol that is used at this layer.
What is IP?
IP - Internet Protocol
The protocol data unit called at this layer.
What is TCP segment?
TCP Segment: At the transport layer, TCP splits all of this data up into many segments.
The protocols at this layer.
What are HTTP, SMTP, FTP?
HTTP: HyperText Transfer Protocol
SMTP: Simple Mail Transfer Protocol
FTP: File Transfer Protocol
The the smallest representation of data that a computer can understand.
What are bits?
A bit is the smallest representation of data that a computer can understand. It's a one or a zero.
A MAC address has how many octets.
What are 6?
A MAC address is a unique, 48-bit hexadecimal number consisting of 6 octets.
It's usually six sets of two digits or characters, separated by colons. An example MAC address would be 00:00:5e:00:53:af.
The protocol data unit called at this layer.
What are datagrams?
Datagrams:
The order of the TCP flags that make up the Three-way Handshake.
What is SYN, SYN/ACK, ACK?
The protocol used to send and receive emails.
What is SMTP?
Simple Mail Transfer Protocol, SMTP − Protocol used for sending and receiving electronic mails (e-mails) via the internet.
The type of modulation used by twisted pair cable computer networks?
What is line coding?
Line coding allows devices on either end of a link to understand that an electrical charge in a certain state is a zero, and in another state is a one.
The protocols that are used in this layer.
What are Ethernet and Wi-Fi?
This field of an IP datagram is decremented by one.
What is the TTL field?
TTL - Total Time to Live: The number of routers (hops) it can pass through before the packet is discarded
At every router hop, the TTL field is decremented by one until it reaches zero, causing the datagram to be discarded.
Video companies use this protocol to stream videos.
What is UDP?
UDP: User Datagram Protocol
The main purpose of UDP is for fast and reliable internet applications usage and data transfer and don't require data verification and security services. UDP has very less bandwidth and latency which makes it work even in terrific network connections.
The protocol used to transfer files between client and servers over the network.
What is FTP?
File Transfer Protocol, FTP − It is a client-server based protocol for transfer of files between client and server over the network.
Allows for communication in two directions at the same time.
What is Full duplex?
Used to determine when the communications channels are clear and when the device is free to transmit data.
What is CSMA/CD?
CSMA/CD - Carrier-sense multiple access with collision detection.
Basic routing tables contain 4 columns.
What are the destination network, next hop, total hops and interface columns?
Destination network, this column would contain a row for each network that the router knows about, this is just the definition of the remote network, a network ID, and the net mask.
Next hop, this is the IP address of the next router that should receive data intended for the destination networking question or this could just state the network is directly connected and that there aren't any additional hops needed.
Total hops, this is the crucial part to understand routing and how routing tables work, on any complex network like the Internet, there will be lots of different paths to get from point A to point B. Routers try to pick the shortest possible path at all times to ensure timely delivery of data but the shortest possible path to a destination network is something that could change over time, sometimes rapidly, intermediary routers could go down, links could become disconnected, new routers could be introduced, traffic congestion could cause certain routes to become too slow to use.
Interface, the router also has to know which of its interfaces it should for traffic matching the destination network out of.
The 6 TCP Control flags.
What are URG, ACK, PSH, RST, SYN, and FIN?
URG - Urgent
ACK - Acknowledged
PSH - Push
SYN - Synchronize
RST - Reset
FIN - Finish
The protocol that web traffic (web browsers) use to communicate to web servers?
What is HTTP/HTTPS?
Hypertext Transfer Protocol Secure
All of these different web browsers and web servers have to communicate using the same HTTP protocol specifications in order to ensure interoperability.