What is the Client Server Model? | System Design Concepts
Summary
TLDRThis video script delves into the client-server model, a fundamental concept for developers. It explains the roles of clients, which request information, and servers, which provide it, often through APIs using HTTP. The script also contrasts this centralized model with the decentralized peer-to-peer model, exemplified by torrent networks. The video aims to educate viewers on how information is exchanged over the internet.
Takeaways
- đ **Client-Server Model Definition**: The client-server model is a fundamental concept for understanding how machines communicate and exchange information over the internet.
- đ» **Client Roles**: Clients can be web browsers, mobile devices, or programs that request information from servers, similar to customers ordering in a restaurant.
- đ **Server Functions**: Servers act as providers of information, which can be stored locally or accessed from other systems, such as databases.
- đĄ **Communication Protocol**: Clients and servers communicate using network protocols, with HTTP being the most common.
- đ± **Client Diversity**: Clients are diverse, including browsers, devices, and programs, all of which interact with servers to request data.
- đ **Server-Database Connection**: Servers are often connected to databases, retrieving data from them in response to client requests.
- đ **APIs as Contracts**: Application Programming Interfaces (APIs) serve as contracts between clients and servers, defining how information is requested and provided.
- đ **Request-Response Cycle**: The client-server interaction involves clients making requests and servers responding with the requested data or performing operations.
- đ **Centralized vs Decentralized**: The client-server model is centralized, with servers holding authoritative information and clients being decentralized requesters.
- đ **Peer-to-Peer Alternative**: The peer-to-peer (P2P) model contrasts with the client-server model by having each participant act as both a consumer and producer of information, without a central server.
Q & A
What is the client-server model?
-The client-server model is a concept in computing where a client, which can be a web browser, a mobile device, or a program, requests information from a server, which is the provider of information. This model is fundamental to how machines communicate and exchange data over the internet.
What are the common examples of clients in the client-server model?
-Common examples of clients include web browsers like Firefox, Chrome, or Safari, mobile devices such as iPhones or iPads, and programs written in languages like Python, Java, or C++ that run on a computer.
How does a client communicate with a server?
-A client communicates with a server using a network protocol language, with HTTP (Hypertext Transfer Protocol) being the most common one. The client makes a request to the server, which then responds with the requested information.
What is the role of a server in the client-server model?
-In the client-server model, the server acts as the provider of information. It may have access to information stored locally or it may know how to retrieve it from another source, such as a database. The server also exposes APIs (Application Programming Interfaces) that define the contract for how clients can request information or services.
What is an API in the context of the client-server model?
-An API (Application Programming Interface) in the client-server model is a set of rules and protocols for building and interacting with software applications. It defines how clients can request information or services from a server, and what data the server will return in response.
How does the client-server model facilitate the exchange of data over the internet?
-The client-server model facilitates data exchange by allowing clients to make HTTP requests to servers. The server then retrieves the requested data, possibly from a database or another server, and returns it to the client via APIs, fulfilling the contract established by the API.
What is the centralized approach in the client-server model?
-The centralized approach refers to the concept where servers act as the single source of authoritative information in the client-server model. Clients are decentralized and exist anywhere on the internet, but they rely on centralized servers to provide data and functionality.
What is the difference between the client-server model and the peer-to-peer model?
-In the client-server model, there is a clear distinction between clients that request information and servers that provide it. In contrast, the peer-to-peer model is decentralized, with each participant acting as both a consumer and a producer of information, sharing equally in the network.
How does the peer-to-peer model work?
-In a peer-to-peer model, each participant in the network can both request and provide data to other participants. There is no central server; instead, participants share resources and information directly with each other, as seen in networks like BitTorrent.
Why is the client-server model essential for developers?
-Developers need to understand the client-server model because it is fundamental to building applications that communicate over the internet. Whether they are building client components, server components, or something in between, this model is crucial for how applications interact and exchange data.
What are some alternatives to the client-server model mentioned in the video?
-The video mentions peer-to-peer (P2P) as an alternative to the client-server model. In a P2P model, there is no central server; instead, each participant acts as both a client and a server, sharing resources and information directly with others in the network.
Outlines
đ Introduction to the Client-Server Model
The paragraph introduces the concept of the client-server model, which is fundamental to how machines communicate and exchange information over the internet. It emphasizes its importance for developers and those aspiring to be developers, as it is integral to building applications. The video's agenda includes defining the roles of clients and servers, explaining their relationship and how they work together, and discussing alternatives to the client-server model. Clients are described as entities that request information, such as web browsers, mobile devices, or programs, while servers are the providers of information. The paragraph uses the analogy of a restaurant to explain the client-server relationship and mentions HTTP as the common protocol for communication between clients and servers.
đ How Client-Server Interaction Works
This paragraph delves into the mechanics of the client-server interaction. It explains that when a client calls an API, the server retrieves information, possibly from a database or another server, and then returns it to the client. The client can then display this information to the user, who can take actions that lead to further requests. The paragraph highlights the internet's reliance on this model for information exchange and contrasts it with a centralized approach, where servers hold authoritative information and clients are decentralized. It also introduces the peer-to-peer (P2P) model as an alternative, where each participant acts as both a consumer and a producer of information, without a centralized server. The paragraph concludes by summarizing the client-server model's role in providing internet functionality through API calls and data exchange.
Mindmap
Keywords
đĄClient-Server Model
đĄClient
đĄServer
đĄAPI (Application Programming Interface)
đĄHTTP Request
đĄCentralized Approach
đĄDecentralized
đĄPeer-to-Peer (P2P)
đĄDatabase
đĄInformation Exchange
đĄNetwork Protocol
Highlights
The client-server model is essential for understanding how machines communicate and exchange information over the internet.
Developers need to know the client-server model to build applications with client or server components.
Clients in the client-server model are entities that request information, like web browsers, mobile devices, or programs.
Servers provide information and can be physical machines, virtual servers, or a concept representing data providers.
Servers are often tied to databases and retrieve information from them when requested by clients.
Servers expose APIs, which are application programming interfaces that define how clients can request information or actions.
Clients make HTTP requests to servers to get information, using protocols like HTTP.
The client-server model involves a client making a request and a server responding with the requested information.
Clients don't need to know the details of how servers operate; they just need to know how to request what they want.
Servers can communicate with other servers or databases to fulfill client requests.
The client-server model is centralized, with servers as the authoritative source of information.
Centralized servers are key to the client-server model because they provide the data necessary for rich functionality.
The peer-to-peer (P2P) model is a decentralized approach where each participant acts as both a client and a server.
In P2P networks, participants can request data from and provide data to each other, unlike the centralized client-server model.
The client-server model enables the internet to have rich functionality by allowing data exchange through APIs.
The video provides a comprehensive overview of the client-server model and its importance in modern computing.
Transcripts
what is going on everyone in this video
we are going to be talking about the
client server model and the client
server model is an extremely important
concept in terms of
how machines communicate with each other
and how they exchange
information over the internet if you're
in it
or if you're a developer or you're
looking to become a developer
the client server model is an essential
concept that you need to know about
because you're going to be using it when
you're building your applications you're
either going to be building client
components or server components
or perhaps something in between so in
terms of the agenda for this video
first we're going to briefly just define
what the client and server
are in the context of the client server
model then i'm going to go over the
relationship between these two
components and how the client server
model works
and then finally we're going to talk
about some of the alternatives to the
client server model
towards the end of the video so that's
what we're going to be talking about so
let's get right into it
and over here on the left i already have
kind of the icons that are
giving you a clue as to what i'm talking
about here but as you can imagine
all of these things on the left hand
side of your screen over here these are
all
clients so clients can be in this case
web browser so you know firefox browser
chrome or safari they can be
something like an iphone or an ipad or
some kind of tablet device
or they can be a program such as a
python java or c
plus plus program that is running on
your computer
so clients in in this context in the
client server model
are the ones that are requesting
information they need
they want information they want to get
it from somewhere and that's how they
get the name the client you know like if
you go into a restaurant and you order
something you want something you're the
client
and the restaurant is the resource and
that's where the the server kind of
comes in
so in the client server model the
clients are any of these three things
they could be browsers devices or even
programs that are running on other
computers
but the common thing between them all is
that generally they speak to servers
in some kind of network protocol
language http is probably the most
common one these days so these are some
different examples of
clients in the client server model so
just to reiterate they want to
get information from somewhere else now
the next obvious question
in this is where is that something else
or what is that something else
and that's where the server comes in the
server
and the server doesn't necessarily have
to be a
single physical machine it's more of a
concept
so if it helps you you can imagine it as
like a physical
machine like a physical computer that's
that's receiving traffic but it doesn't
necessarily have to be that it could be
different virtual servers that are
within a certain machine
but generally in the client server model
we're just kind of thinking about the
concepts here
uh so the server in this relationship is
the provider of information
so let me just write that out for you so
the server is often called
the provider provider
and it's called the provider because it
has access to some kind of information
it doesn't necessarily need to have that
information stored locally it could just
know how to get it or where to get it
from
that's basically the role of the server
so typically what you see these days is
that a server usually
is tied to some kind of database
somewhere that may exist on some other
system
and then say this this blue icon here is
your database and then when a request
comes into the server it just goes and
retrieves that from the database
and then grabs that data the database
responds and then the server kind of
responds with that information back to
the client but we're going to go over
that whole relationship in just a moment
uh so that server exposes a set of apis
also known as application programming
interfaces
uh think of this like the contract in
which if you give me something i'll give
you something back
uh that's what an api essentially is if
you want more detail on an api i have a
whole video on that
i'll put that in the description section
below but in the
client server model i think we're moving
on to the next section now
um in the client server model the server
provides the client wants something
and you have this kind of dance that
goes on between them
the client requests information
generally through what's called a http
request
http request which stands for hyper text
transfer protocol so the general theme
is that you have these clients over here
and these clients make requests to a
server and the server receives that
request goes out and grabs it maybe from
a database
it's also possible that this server here
talks to another server and it goes and
gets some information
from that server and then maybe this
server queries a different database
but the general idea is that this server
through its apis just put a little box
here
to denote that it exposes apis uh
it knows how to go and get information
or perform some kind of operation
that is agreed upon or known by the
client
and the client doesn't necessarily need
to know how the server works or how it
does its job or where it stores its
information
or any of the details here the client
just needs to know who do i call to do
what i want to do
and what do i get back from the server
now now completing this example when the
client calls this api
the server is going to get that
information it's going to maybe query
some database call another server like i
already said
and return that information back to the
client
and then the client can observe that
information it can show some uis or some
user interfaces or some buttons on the
screen
and then the client or the user can
perform some other kind of action that
makes another request to a different
server
so this is generally how the client
server model works you have your clients
which are usually browsers programs or
some kind of input devices you have
servers that are listening
for traffic on certain ports they have a
contract or an api
associated with them and when that api
is called
the server knows how to perform a
certain job and return
results back to the client and this is
how the internet works it's how
information travels between
you know the the device in your pocket
and a server sitting somewhere
in the internet it could be anywhere in
the world but as long as your client
knows how to talk to a server
you know it doesn't matter where that
server is located as long
as this contract is being upheld and a
term that usually goes hand in hand with
a client server model
is what's called the centralized
approach or
centralized framework and they're called
centralized because these servers
are the kind of single source where all
this information this authoritative
information
is located and the clients are kind of
decentralized in this relationship
they are existing anywhere on the
internet but the servers are the ones
that are really the
the key to this relationship because
they are the data providers and without
data you can have rich functionality
i mean if you think about it if you're
logging into your bank's website through
you know your firefox browser or
something
your browser itself doesn't allow you to
do that much the only way that you get
rich information you get rich
functionality out of using your browser
is by interacting with servers on the
banking systems network
so that you can go and get the account
balance and pay bills and do all these
different things
so in this way it makes sense to think
of the server as the centralized
component in this relationship
and the opposing concept or the opposing
philosophy in contrast with the
centralized approach
is what's called the p2p or peer-to-peer
peer to peer
and let me just scroll down a little bit
maybe make a little bit more room here
and the peer-to-peer approach is what
you would think of
in terms of like a bittorrent network or
a torrent network so
you have different folks that all
download a torn file and if you don't
know how torrents works like this is
essentially how it works i'm going to
explain it to you right now
so there's multiple people that download
this torrent file so maybe there's like
three actors in this story
so each person in this relationship that
has downloaded this file
acts as both a consumer and a producer
so they
are in our client server model both a
client and a server of information
so with every other participant in this
relationship you
can request data from a different
participant and you can also receive
requests for data that you have
and this is why it's kind of a
peer-to-peer relationship everyone else
that is in this network
can kind of feed off of each other so
that there's no
centralized approach one there's no one
key player in this relationship
that holds all the goods and that's what
we saw in the server model
so this is how it's different the
peer-to-peer model is decentralized
everyone shares an equal role everyone
is both a producer and a consumer
um so this is the idea of the client
server model
and just to recap we have the clients
like your browser your phone or just
programs in general
that are the requesters of information
we have these servers which are the
resources or the providers of
information
and data is exchanged through apis in
which the client
calls a particular api on a server that
is listening on a particular port
and the server responds with that
information and that's how the internet
gets awesome functionality
so i hope you enjoyed this video i have
another great one on apis which you
should check out on the right
here and as always if you like this
please don't forget to like and
subscribe and i'll see you next time
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