CSCI 2700 midterm review

what are the layers of the osi model in order?

Application (7)
Transport (4)
Network (3)
Data link (2)
physical (1)

How does data flow through the OSI model when sending from one person to another?

starts at the Application Layer, moves down the OSI layers, travels across the Internet, then moves back up the OSI layers in reverse, and reaches the receiving person back at their Application Layer.

what is forwarding?

To move traffic from one router to another

How is network bandwidth measured?

By the transmission rateWh

What are the main sources of delay in sending data from one point to another?

Transmission delay, Propogation delay, and Queing delay

What is network congestion?

When there is too much traffic on a network

Why do we define protocols?

To manage and control the network

What is Ethernet?

A family of wired connection devices used in home and commercial buildingsH

How many outcomes are there of excessive packets being sent over a network? and what are they?

Two. Buffer packets and/or drop packets

Does UDP have a strategy for excessive packets being sent over a network.

No

True or False: In a client-server model, servers need to have a static IP address

True

What different types of IP addresses can clients use

Static or dynamic

How do computers communicate

IP adresses

How do humans communicate with computers over the internet

Domain names

How do you translate a domain name into an IP address?

DNS server

What is the hierarchy for a DNS server

root, top level domain, and authoritative

What server usually hosts query first

Local DNS server

What is TCP?

A full-duplex point to point connection

True or False: TCP supports multiple objects and multiple ACKs between client and server

True

what does an internet protocol is stateless mean?

that they don’t remember anything between calls from point-to-point

What is a strategy for recalling the state between calls

cookies

What are the two main protocols

TCP and UDP

What does data pass through when data is sent from one machine to another

A socket

idk

idk

what does TCP send

packets

what does UDP send

datagrams

What is the data called that TCP and UPD send

A message

What is UPD also refered to as?

“Fire and Forget”

Describe UDP and what it does

sends data as fast as possible from one point to another. There are no guarantees in UDP that the data will be transferred at all or if the data will arrive in order. There is a checksum feature in UDP to check for corrupted packets, but this checksum feature is prone to errors and is optional to use.

What four pieces of info does UDP need?

source port, destination port, checksum, and length of the payload

How many bytes per packet does all the info in UDP send

8 bytes

When is it okay for someone to use UDP for an application?

If they are okay with some data being lost in transit

Describe TCP.

it is an attempt at creating a protocol for reliably sending data over an unreliable network.TCP uses the same checksum features as UDP, but unlike UDP, the checking the packet for corrupt data is required. TCP provides guarantees that all packets arrive in the correct order and if packets are ever lost or delayed in transit, those packets are resent.

How many bytes per header information does TCP need

20 bytes

When should one use TCP?

When they need 100% of your data reaching its destination and are willing to wait

What is a 3-way handshake?

first, the client sends a SYN packet to the server. Second, the server sends a packet that is both an ACK of the first packet and a SYN to establish a connection with the client. Third, the client sends back an ACK packet to the server in response to the server’s SYN. Only then will data begin to freely transmit between client and server over TCP.

true or false: TCP does not use 3-way handshake.

False