welcome to the Cisco netacad introduction to networks video series by
Jason Johnson this video is module three part 1 of 2 module 3 protocols and
models what we're gonna be covering in this module is the rules describe the
type of rules that are necessary to successfully communicate protocols
explain why protocols are necessary in a network communication setting protocol
Suites standard organizations reference models data encapsulation and data
access the rules Network scans vary in size and complexity it's not enough to
have a connection devices must also agree on how they're going to
communicate there are three elements to any type of communication there's gonna
be a sender there's gonna be a receiver and then there's gonna be some type of
medium so if we look here if we have two people trying to communicate and let's
say that one person's trying to speak French and one person is trying to speak
English they won't necessarily understand each other unless they have a
common language unless they say let's say for example they both speak German
then they could communicate with each other or they both speak English so they
have to have a common communication and then they have to be within distance of
each other on the communication so all
communications are governed by protocols when we're talking about the network
setting protocols or the rules that communications will follow and those
rules will vary depending upon which protocol so you have a message here you
get a signal as the transmitter you get the medium which is the copper line or
you have you know Wireless or fiber optics you have a receiver on the other
end and then you have the message destination and just like humans
communicating you have to be able to speak loud enough so you can hear each
other you have to speak in a common language and you have to agree upon a
set of rules you know what language you're going to speak you know how far
away are from each other are you gonna stand so that you can hear each other
and the same way with with devices so if
you gonna have to be connected and then
you're gonna have to speak a common language now when we establish rules
individuals must use established rules or agreements to govern the conversation
the first message is difficult to read because it's not formatted properly the
second one shows the message formatted properly
so if we say humans communication between govern rules it is very
difficult if ace in there so we've written something out but it's not
grammatically correct so if you've ever had an English paper or a paper that
you've tried to write and it doesn't make sense it's because we're not
following a governing set of rules like we do in the English language so if we
said rules govern communication between humans we've got the proper spacing
we've got capitalization we've got punctuation we've got a structure to
everything and we can understand it the same thing happens in networks so
protocols must account for the following requirements an identified sender and
receiver common language speed and timing of delivery in the confirmation
or acknowledgement requirements so common computer protocols must be an
agreement and include the following message encoding how's it going to be
encoded message formatting and encapsulation the size of it the timing
of it and the message delivery options so let's take a look at encoding first
encoding is the process of converting information into another acceptable form
for transmission decoding reverses that process to interpret the information so
we encode it we transmit it we decode it very simple message formatting and
encapsulation so just like we send a letter we write a letter and we put it
in an envelope and we address it so we have the sender we have the receiver and
we have postage to be able to deliver that which is our timing or how fast
it's going to get there so when a message is sent it must use a specific
format or structure message formats depend on the type of the message and
the channel that's used to deliver the message so here we have a packet and so
we say how many bytes it's going to be what it's going to include and then we
can see how the packet is broken down so we have our version our traffic class or
flow layer we have our source in our destination
sender receiver and we have our size now the message size that encoding between
hosts must be an appropriate format for the medium so messages sent across the
network are converted to bits ones and zeros
the bits are encoded into a pattern of light sound or electrical impulses light
it's gonna be bursts of light sound it's gonna be wavelengths or electrical
impulse is gonna be pulses of electricity so the destination host must
decode the signals to interpret the message if it's not being able to decode
that you just won't get the signal so the packets won't go through and that's
where we get to timing so a timing message timing includes the following
flow control response timeout and access method flow control manages the rate of
data transmission and defines how much information can be sent and the speed at
which it can be delivered response time out just means that is how long a device
waits if it doesn't hear a reply from the destination then it stops and what
stops waiting for it and then access method determines when someone can send
a message there may be various rules governing issues like collisions this is
when more than one device since traffic at the same time and the messages become
corrupt a collision is you have multiple devices trying to send and the packets
get bumping into each other so some protocols are proactive and attempt to
prevent collisions and other protocols are reactive and establish a recovery
method after the collision occurs message delivery options message
delivery may use one of the following methods unicast multicast or broadcast
and I'll show an image here on the next slide that helps a little bit with that
broadcast are used in ipv4 networks but are not an option in v6 and later on
we'll also see any cast as an additional delivery option for ipv6 so let's look
at the next delivery here so when we're talking about a unicast unicast is and
this is the way the easiest way for me to remember it unicast one goes from one
sender to one receiver one sender to one receiver all the rest of them getting
node so this is gonna multicast these are going to go to mall
or multiple receivers so you have one sender of multiple receivers and then
broadcast means it's a broad area so it broadcast to everything that's in my
mind how I remember those three unicast one multicast mini and broadcast
everybody protocols network protocol overview is network protocols define a
common set of rules they can be implemented on devices and software
hardware are both areas and protocols have their own function format and rules
so if you have a protocol type that's network communication that enables
network communications it enables two or more devices to communicate over one or
more networks network security is another type that secures data to
provide authentication data integrity and data encryption and routing enables
routers to exchange route information compare path information and select best
paths and then we have service discovery that's used for the automatic detection
of devices or services network protocol functions devices use agreed-upon
protocols to communicate and protocols may have one or more function they can
address they identify the sender and receiver reliability provides guaranteed
delivery flow control that ensures the data flows at an efficient rate
sequencing labels each transmitted segment of data error detection
determines if data become corrupted during a transmission let's say you lost
some packets or you had an interference that's what error detection does for you
an application interference is the process to process communications
between Network applications here we have the example of this users gonna
send the message across the network using v4 they can forward the message
because they understand the v4 header and it fords it on through and they can
accept the message because they understand the v4 method now protocol
interaction networks require the use of several protocols and each protocol has
its own function and format so hypertext protocol or hypertext Transfer Protocol
HTTP you're most familiar probably with HTTP because that's a web page HTTP
would be hyper Transfer Protocol secure this one governs the way a web server or
web client interacts transmission control protocol manages
the individual conversations provides guaranteed delivery and manages flow
control internet protocol delivers messages globally from the sender to the
receiver and Ethernet that layer one you can start seeing the layers here
delivers messages from one NIC to another neck on the same Ethernet local
area network protocol Suites network protocol Suites protocols must be able
to work with one with each other so a protocol suite is a group of
interrelated protocols necessary to perform a communication function sets of
rules that work together to help solve a problem and the protocols are viewed in
terms of layers so you have higher layers and lower layers so you have your
content layer and you have your rules layer and then your physical layer now
let's take a look at this on the evolution of protocol Suites here so you
have Internet Protocol suite or tcp/ip that's the most common protocol suite
and it's maintained by the IETF the internet Engineering Task Force you have
the open systems interconnection protocol or the OSI and that's where
most likely you hear the OSI model the seven layers you know layer one through
you know please do not you know physical layer and on up open systems internet
connection but it's maintained by the ISO the international organizations for
Standardization and the ITU the International Telecommunications Union
appletalk is a proprietary suite released by Apple and Novell was by
Novell there was Microsoft had their own proprietary suite at one point most of
these aren't used anymore back in the 90s I use Novell quite a bit I was
working on Novell networks and but those have went by the wayside here's we have
the layer here you have our tcp/ip layer name so you have your HTTP DNS DHCP at
this location layer ISO governs these appletalk was aft AFP so you really
don't need to memorize these over here you might see these on some legacy exams
or just kind of be familiar that there was Apple talk in Novell and some
Microsoft protocols but the main ones we're using today or tcp/ip and iso
tcp/ip protocol example so tcp/ip protocols operate at the application
transport and internet layer internet layers the most common network access
layer LAN protocols are Ethernet and W and wireless LAN so Ethernet that's a
cable cables that you plug in and your wireless LAN that you connect from your
devices and if we look at this packet here so we have a packet being sent from
a web server to a end host across the internet and we look at that the
application is our HTTP that's letting us know that it's a web page the
transmission control protocol is TCP the internet protocols IP and we're sending
that across a cable Ethernet copper tcp/ip is the protocol suite used by the
internet and it includes many different protocols it's open standard it's freely
available to the public and can be used by any vendor so anybody that wants to
start creating new hardware and start sending things on the internet you know
connecting devices can use the tcp/ip open source a standards-based protocol
suite that is endorsed by the networking industry and approved by the standards
organization to ensure interoperability let me say that again interoperability
that just means that they can work together devices if you have a tcp/ip
device and somebody else has a TCP ID bot tcp/ip device you should be able to
connect them together and have them communicate so the process here a
webserver encapsulating and sending a web client example here and a client D
encapsulating the web page so you have a web client that requests a web page the
web server grabs the Ethernet information IP TCP and data information
it encapsulates that in a packet and then sends it across the wire as ones
and zeros the host picks that up and D encapsulates that and it reconstructs
based on the ones and zeros what the Ethernet IP TCP and data information was
and then it reconstructs that web page standards organizations there are a lot
of different standards organizations I encourage you to go out on the internet
and research these be a little bit familiar with some of them the I trip
the internet assigned numbers Authority I am a if you've ever looked into
getting website names the IAEA controls a lot of that IETF itu-t ia I can I I do
encourage you to go out on the internet and look these up and look at what they
control as far as what they oversee they do have open standards they encourage
that because of interoperability competition innovation there
vendor-neutral there's no one company that owns the standard they are
nonprofit organizations and they are established to develop and promote the
concept of open standards now when we look at internet standards the Internet
Society in the internet architecture board and how they're broken down and
they have working groups they have research groups and there are engineers
there's different types of scientists and engineers and different people that
work on these boards and they write out the governing documents for these
standards you have the Internet Society I Sauk internet architecture board IAB
the ATF the IRT F internet research task force and what each one of those does
promotes open development folks don't long-term research and again I encourage
you to read a little bit more about the organizations there ICANN is the
internet corporations of Assigned Names and numbers so your web names come
originally from ICANN then you have the I am a and then they give out IP
addresses domain names and TCP and UDP port numbers and the internet assigned
numbers Authority IAA and I can a few more here are the I
Triple E Institute of Electrical and Electronics Engineers electronics
industry alliance the telecommunications industry association and the ITU Dashti
International Telecommunications Union telecommunication standardization sector
that's a big one and what each one of these does and what each one areas are
on here this has been module three protocols and models part one of two I
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below I hope you have a great day