CSET2200 Final

Transport layer(4)

-Multiple applications at once (multiplexing)

-segmentation of data

Segmentation of data?

by ports

sections of ports

Well-known 0-1023

registered

Private

Registered is private

65536 ports with 0 unusable

TCP vs UDP

TCP - Reliable and connection orientation, 3 way handshake

UDP - Unreliable and connectionless

TCP dump

Raw data

First IP source

port

Second IP source

port

IANA

They assign the ports to the applications

What is DNS

DNS - Domain Name System,

DNS resolves IP address from domain name

look at local DNS cashe

Send/request questions to DNS server

if respond in last 24 reply w/ address

if not try to resolve

Talks to authority server

Browser Cashe

Brings text from data file and pushes up

Host File

these can't be removed unless told to

all must match to resolve DNS

rightmost lable until \

.com/,org top-level domain

answer from cashe?

Unauthoritative- probably from IP address

Answer from DS?

Authoritative

Session Layer

tracks segments of session

protects data by keeping sessions separate

specific port = socket

Presentation Layer(6)

Presents to layer above and below

has to massage data with encryption and compression

Encryption an compression direction

the direction is down the OSI model

Application layer(7)

asks input from user

not all protocols ask for input(DHCP)

IOT

Internet of things - anything remotely controlled

IIOT

Industrial Internet of Things

reliable

acknowledgments

can take a lot of beating

deal with harsher conditions

Difference between Ethernet and Industrial Ethernet

Ethernet is for the office

Industrial Ethernet is for the plant setting

When ARP is sent out does everything have to respond?

No

What is a virtual LAN

Different broadcast domains(limits broadcast messages)

How to communicate between Vlans

Router

No vlan?

Flat Network

Number Scheme for Wi-fi

802.11

Who controls Wi-fi

IEEE

what s Wi-fi?

RadioWaves

Radiowaves are broken into? and what are they

Bands, group of frequency's

what is a channel

center of group of frequency

Two types of channels

- overlapping - shared frequency between channels

-Non Overlapping - not shared

Wi-fi bands?

2.4

2.5

6E

all in gigahertz

Repeater versus Extender

Repeater - takes signal, strengthens and sends out stronger, but it takes away half of bandwidth

Extender - another access point

WPA, WPA2, WPA3, WEP

Encryption of data

Encryption from client to router

WEP weakest

Strongest Strongest

WPA2 - mostly used

Wifi 6E

supports WPA2 and WPA3

PLC devices

Programable logic controller

all over the place

use Industrial ethernet to communicate

more bulky

How to protect PLC with communication

isolate Industrial ethernet

treat network as border

firewall between Ethernet and IE

a socket is made up of

port and IP address