TCP IP Model Explained | TCP IP Model Animation | TCP IP Protocol Suite | TCP IP Layers | TechTerms
Summary
TLDRThis script explores the fundamentals of communication in computer networks, emphasizing the importance of shared protocols like TCP/IP for successful data exchange. It explains the layered structure of network communication, detailing each layer's role from the physical to the application layer. The script clarifies the distinction between TCP and UDP, highlighting TCP's reliability and UDP's efficiency. It also delves into concepts like MAC and IP addressing, routing, and the significance of the OSI model in networking research.
Takeaways
- 🌐 For successful communication, both parties must share a common language or message format, which in computer networks, is referred to as a protocol.
- 💬 In computer networks, the message format includes information such as message length, data content, and sender/receiver addresses to ensure successful communication.
- 🔠 If computers use different character encodings like ASCII and Unicode, translations are necessary for successful communication unless a common standard is agreed upon.
- 📚 TCP/IP is a set of protocols that facilitate network communication, including the transmission of various digital forms such as files, voice, and video.
- 🔄 TCP breaks messages into segments and IP handles routing these segments to their destination, with the receiver's TCP module reassembling them into the original message.
- 🔄 TCP stands for Transmission Control Protocol, ensuring reliable communication, while UDP (User Datagram Protocol) is less reliable but faster.
- 🌐 The OSI model and TCP/IP model are network models; the former is for research, and the latter is practical and used in the Internet.
- 🔀 The TCP/IP protocol suite includes multiple layers, each with specific functions, from the physical layer that deals with actual signal transmission to the application layer that generates messages.
- 🔌 The physical layer is responsible for converting binary data into signals suitable for the transmission medium, such as electrical, light, or radio signals.
- 🔗 The data link layer, including MAC and LLC sublayers, manages data encapsulation, media access, flow control, and error detection using Ethernet frames.
- 🛣️ The network layer, also known as the internetworking layer, is in charge of logical addressing, routing, and path determination using IP addresses.
- 🔒 The transport layer uses TCP for reliable, ordered data transfer with features like error checking, retransmission of lost data, and congestion control, while UDP is used for less reliable but faster communication without these features.
- 🌟 The application layer interacts with user applications, providing protocols for accessing network information and services such as HTTP, FTP, and SMTP.
Q & A
What is the fundamental requirement for successful communication between two people?
-For successful communication between two people, they must share a common language and be able to understand each other.
Why is a common message format necessary in computer networks?
-A common message format is necessary in computer networks to ensure that computers can understand the length of the message, the data part, and the sender's and receiver's addresses, leading to successful communication.
What is the role of protocols in computer networks?
-Protocols in computer networks are the agreed-upon set of ground rules that facilitate communication by establishing standards for data exchange and addressing.
How does the TCP/IP protocol suite support network communication?
-The TCP/IP protocol suite supports network communication by providing a set of protocols that handle various aspects of data transmission, including message segmentation, routing, and ensuring reliable data delivery.
What is the main difference between TCP and UDP protocols?
-TCP is highly reliable but slower, ensuring in-order delivery and error checking, while UDP is less reliable but generally faster, lacking some of the reliability features of TCP.
What is the purpose of the OSI model in network communication?
-The OSI model, or Open System Interconnection reference model, is primarily used for research and provides a framework for understanding and designing communication systems, different from the practical TCP/IP model.
What is the significance of the Application layer in the TCP/IP model?
-The Application layer is the topmost layer in the TCP/IP model, responsible for generating messages and interacting with user applications to perform network-related activities.
How does the Physical layer in the TCP/IP model contribute to communication?
-The Physical layer is responsible for converting binary sequences into signals suitable for transmission over various types of media, such as copper cables, optical fibers, or air for wireless communication.
What is the function of the Data Link layer in the TCP/IP model?
-The Data Link layer is responsible for data encapsulation, accessing the media, error detection, and flow control, ensuring reliable transmission of data within a network.
What are the key functions of the Network layer in the TCP/IP model?
-The Network layer is responsible for logical addressing, routing, and path determination, ensuring that IP packets are directed to their correct destination across different networks.
How does the Transport layer ensure reliable data transfer using TCP?
-The Transport layer ensures reliable data transfer using TCP through features like connection establishment, error-free data transfer via checksums, ordered-data transfer with sequence numbers, retransmission of lost data, discarding duplicate packets, and congestion throttling.
What are some common protocols used by the Application layer for accessing network information?
-Some common protocols used by the Application layer include DNS for translating IP addresses and domain names, DHCP for assigning IP addresses, FTP for file transfers, HTTP for web page transfers, and SMTP for email messaging.
Outlines
🗣️ Communication and Protocols in Computer Networks
This paragraph discusses the fundamental concept of communication, emphasizing the need for a common language or protocol in both human interaction and computer networking. It explains that for successful communication, computers must share a common message format and understand various aspects of the message, such as length, data, and addresses. The paragraph introduces the TCP/IP protocol suite as a set of rules that facilitate network communication, contrasting it with the OSI model, which is more theoretical. It also touches on the basic concept of a network and communication, describing how data is sent in digital form and broken into smaller units for transmission.
🔌 The Physical Layer and Data Link Layer Basics
The second paragraph delves into the physical layer of networking, which is responsible for the actual transmission of digital messages as signals over various media. It mentions Ethernet as a common protocol and discusses different types of cables used for transmission. The paragraph then transitions to the data link layer, highlighting its two sublayers: MAC and LLC. The MAC sublayer is described as handling data encapsulation and media access, with CSMA/CD as its access method. The LLC sublayer is responsible for flow control and error control, ensuring that data transmission is managed without overwhelming the receiver and that errors are detected and corrected through ARQ.
🌐 Understanding Routing and the Network Layer
This paragraph explains the network layer's role in logical addressing, routing, and path determination. It describes how IP addresses are assigned to ensure correct delivery and how routing is essential for moving packets between different networks. The paragraph also illustrates the process of routing with an example involving two networks and a router, explaining how ARP is used to resolve MAC addresses within the same network and how routers forward IP packets to their destination. Path determination is discussed as the process of choosing the best route for data delivery, with protocols like OSPF, BGP, and IS-IS being mentioned.
🚀 Transport Layer Functions and TCP/UDP Protocols
The fourth paragraph focuses on the transport layer, detailing the functions of TCP and UDP protocols. It explains that TCP provides reliable, ordered data transfer with features like error checking, retransmission of lost data, and congestion control, while UDP is faster and less reliable, lacking these features. The paragraph outlines the three phases of data transmission via TCP: connection establishment, data transfer, and connection termination. It also describes the process of the TCP three-way handshake for establishing a connection and the four-way handshake for termination. The paragraph concludes by mentioning the role of the transport layer in segmenting messages and the use of UDP for protocols like DNS, DHCP, SNMP, and RIP.
🌐 Application Layer and Internet Protocols
The final paragraph discusses the application layer of the TCP/IP model, which interacts with user applications to facilitate network communication. It describes the layer as providing access to network information and lists several protocols associated with it, such as DNS, DHCP, FTP, HTTP, IMAP, IRC, POP3, and SMTP. Each protocol is briefly explained in terms of its function, such as DNS for translating IP addresses to domain names, DHCP for assigning IP addresses, and SMTP for email transfer. The paragraph concludes by encouraging viewers to like and share the video for educational purposes.
Mindmap
Keywords
💡Communication
💡Protocols
💡TCP/IP
💡Network
💡Data Units
💡Ethernet Frame
💡MAC Address
💡IP Address
💡Routing
💡ARP
💡UDP
💡TCP
💡Application Layer
Highlights
Communication between two parties requires a common language or protocol.
In computer networks, a common message format is essential for successful data exchange.
Protocols are the agreed-upon rules that facilitate communication in computer networks.
TCP/IP is a set of protocols that support network communication, including the internet.
A network is formed by two computers connected via LAN Cable using Network Interface Cards.
Messages are broken into small data units for transmission and reassembled at the receiver.
TCP segments messages into small units called segments, while IP handles routing to the destination.
TCP is reliable but slower, while UDP is faster but less reliable.
TCP/IP is a practical model developed for the original Internet design, unlike the OSI model used for research.
The TCP/IP model consists of multiple protocols layered at different levels.
The Application layer generates messages that are passed down to lower layers for encapsulation.
The Physical layer is responsible for converting binary data into signals for transmission.
The Data Link layer manages data encapsulation and media access with protocols like Ethernet.
The Network layer handles logical addressing, routing, and path determination with protocols like IP.
Transport layer protocols like TCP and UDP provide services such as flow control, error control, and packet sizing.
TCP ensures reliable data transfer through a three-way handshake, error checking, and congestion control.
The Application layer uses protocols like HTTP, FTP, and SMTP for various internet services.
Transcripts
Suppose two persons are to communicate with one another.
To communicate successfully, they should be sharing a common language.
Therefore, both ends should be able to understand what the other person is saying.
Similarly, in computer networks, the computers should be sharing a common message format.
They should know how long the message is? Which part of the message is the
actual data? Which part of the message is the sender's and receiver's address?
Such information will result in successful communication between computers.
If one computer speaks ASCII and the other speaks Unicode, successful communication
will not occur unless they are prepared to perform the translations back and forth.
So, some ground rules are required to communicate successfully.
In computer networks, the agreed-upon set of ground rules that make communication
possible are called protocols. TCP/IP is a set of protocols that
support network communication, but what is a network and what is communication?
In the most basic form, two computers connected via LAN Cable sharing data with
the help of Network Interface Cards (hardware present in each computer) forms a network,
and the process of sending messages from one place to another through a wired or
wireless medium is called communication. The message can be a file, a voice conversation,
a streaming video or anything which can be communicated in digital form.
These messages are not sent as a single unit; instead,
they are broken into small data units. These data units are transmitted through the network
and restored at the receiver into the original message.
In TCP/IP protocol suite, TCP breaks messages into small data units called segments and hands
them off to IP, which deals with routing segments through the networks to their final destination.
TCP module in the receiver combines the segments to form the original message.
Note that TCP stands for Transmission Control Protocol and IP stands for Internet Protocol.
An alternative to TCP is UDP. It stands for User Datagram Protocol. The main difference is that TCP
is highly reliable, but it is slow, whereas UDP is less reliable but generally faster. Both TCP
and UDP are a part of the protocol suite. However, due to heavy dependence on TCP,
and for historical reasons, the entire set of protocols is referred to as TCP/IP.
TCP/IP is a network model designed to support network communication, even if the computers are
from different manufacturers. There is one more network model called the OSI model or
Open System Interconnection reference model. It is primarily used for research. On the other hand,
TCP/IP is a practical model developed to meet the needs of the original Internet design.
As per the name, TCP/IP seems to be a set of two protocols only – TCP and IP. However,
it consists of numerous protocols bundled at different layers.
The topmost layer is the Application layer which generates a message. The message is passed to the
lower layers at the sending node, where each layer encapsulates the message from the above layer.
So, the message sent becomes larger and larger as it passes down the chain.
The data unit in the data link layer is called an Ethernet frame;
in the network layer, it is called an IP packet; if it is in the transport layer,
it is called TCP segment in case of TCP protocol, and UDP datagram in case of UDP protocol.
In the application layer, it is called an application message.
The peer layer removes the header at the receiving node and passes the remainder
upwards layer-by-layer till the message finally reaches the application layer.
Let us discuss each layer one-by-one in more detail.
We are starting with the bottom-most layer – the physical layer.
The physical layer is the place where actual communication takes place.
We know that a sequence of 0s and 1s digitally represents the messages.
The physical layer converts this binary sequence into signals and transmits them over local media.
The signal can be electrical if the local media is Copper Cable or LAN cable,
the Light signal in case of Optical Fiber and a Radio signal in case of Air/Vacuum.
So, the signal generated by the Physical Layer
depends on the type of media used to connect two devices.
The most common protocol used at the physical layer is Ethernet.
The protocol also specifies the type of cables that can be used for data transmission.
For example, if the protocol used is Ethernet, then twisted pair cable, coaxial cable, or fiber
optic cable can be used for data transmission. If the protocol used is fast Ethernet or gigabit
ethernet, then twisted pair or fiber optic cable can be used as local media.
Next is - THE DATA LINK LAYER The data unit in the data link
layer is called an Ethernet frame. The data link layer is divided into two sublayers:
· Medium-access control or MAC sublayer, and · Logical link control or LLC sub-layer
The MAC sublayer is responsible for · Data encapsulation, and
· Accessing the media In data encapsulation,
the MAC sublayer adds a header and a trailer to the IP packet received from the network layer.
The header contains the MAC addresses of the sender and receiver. The trailer
contains 4 bytes of error checking data used to detect errors in the received Ethernet frame.
What is the MAC address? It is a unique 6-byte address embedded in the NIC of
a device by its manufacturer. For accessing the media, the access
method Ethernet uses is called Carrier Sense Multiple Access/Collision Detection or CSMA/CD.
In this method, each computer listens to the cable before sending data through the network.
If the network is clear, the computer will transmit. If the first computer is already
transmitting on the cable, the second computer will wait and try again when the line is clear.
Sometimes, two computers attempt to transmit at the same instant. When this happens,
a collision occurs. Each computer then stops transmission and waits a random amount of time
before attempting to retransmit. Please note, with this access method;
it is normal to have collisions. However, the delay caused by collisions and retransmitting
is very small and does not normally affect the speed of transmission on the network.
The next is the LLC sub-layer. It offers · flow control, and
· error control Flow control is a technique that restricts
the amount of data that a sender can send without overwhelming the receiver. The receiving devices
have a limited processing speed and a limited memory to store the incoming data. If these limits
are exceeded, then the incoming data will be lost. To avoid this, the receiver should inform the
sender to slow down the transmission rate before these limits are met. In the data link layer, flow
control restricts the number of frames the sender can send without overwhelming the receiver.
Error control in the data link layer primarily refers to error detection and retransmission.
Error detection is done by using the error checking bytes added in the trailer of the frame.
The frame retransmission is done using Automatic Repeat Request
or ARQ. The receiver sends an ACK to the sender when a frame is received.
When the ACK is not received, the sender sends the frame again. So, if a frame gets lost or damaged,
then the ACK is not sent. As a result, the sender sends the frame again. This process
is called Automatic Repeat Request (ARQ). LLC layer can also re-size the IP packets
received from the network layer to fit them in the data link layer frames.
The transport layer provides most of the services of the LLC sublayer,
including flow control, error control, and sizing of packets; therefore, the services
of the LLC layer are usually bypassed. The remaining three layers of the TCP/IP
protocol stack, including network, transport, and application layers,
are implemented as software programs within the computer's operating system.
Starting with the NETWORK LAYER The transport layer passes TCP segments
or UDP datagrams to the Network Layer. The network layer adds logical addresses or IP
addresses to the TCP segments or UDP datagrams to form IP packets and then uses routers to send the
IP packets to other networks. The network layer also determines the best path for data delivery.
So the functions of the network layer are: 1. Logical Addressing
2. Routing 3. Path determination
IP is the single standard protocol for this layer. The TCP/IP network layer is also
called the internetworking layer or IP layer. Logical Addressing: Every computer in a network
has a unique IP address. The network layer assigns sender and receiver's IP addresses
to each segment or datagram to form an IP Packet. IP addresses are assigned to ensure
that each IP packet can reach the correct destination present in different networks.
Routing Routing is
a method of moving an IP packet from source to destination present in different networks. Routing
is not needed if the source and destination computers are present in the same network.
For communications within a network, the task is usually simple.
The ARP module takes the destination IP address from the IP packet and returns the MAC address
of the destination computer. It is then used to create an Ethernet frame which is delivered
directly to the destination as it is present in the same network, . no routing is needed.
However, when the message is being sent to a node outside a network, for example, to the Internet,
the network layer moves the message from sender to receiver through routers. Consider two networks
connected with a router. Computer A needs to send data to computer B. Please note that both
computers are present in different networks. Hence, in this case, routing is needed.
To create an Ethernet frame, we need the MAC address of the destination computer.
However, in this case, the destination is present in a different network. So, the ARP module cannot
provide us with the destination's MAC address because it can provide the MAC address only if
the computers are present in the same network. So, the ARP module in network one cannot provide the
MAC addresses of the computers present in network two and vice-versa. Since the intermediate to the
networks is the router R, the destination MAC address is kept as the router's MAC address, and
the frame is forwarded to the router. Router finds that the MAC address in the frame matches its
address. So, it extracts the IP packet from the frame and forwards it to the network layer. The
network layer finds a mismatch for the destination IP address. So it sends the IP packet down to
the data link layer and updates the destination MAC address with the MAC address of computer B.
But how router knows the MAC address of computer B? Simple, by using the ARP module. It is one
network, so the ARP module works here. Finally, the ethernet frame is delivered to computer B.
Please note that the destinations IP address never changes for inter-network communication,
but the physical address or the MAC address changes with every hop.
So, IP addresses are a must to transfer data among multiple networks.
Now Path determination: A computer can be connected
to an internet server or a computer in several ways. Choosing the best possible path for data
delivery from source to destination is called Path Determination. Layer 3 devices use protocols
such as OSPF (Open Shortest Path First), BGP (Border Gateway Protocol), IS-IS (Intermediate
System to Intermediate System) to determine the best possible path for data delivery.
Because routing takes place at the network layer or layer 3, routers and gateways
are sometimes called layer three switches. IP is unreliable. It does not guarantee delivery
nor check for errors. These tasks are the responsibility of the transport layer.
Let us start discussing the transport layer At the sending node, the transport layer
receives the message from the application layer. When the message reaches the transport layer,
one of the transport layer protocols, i.e., TCP or UDP, is selected.
TCP supports segmentation. So, if the message is large, TCP divides it into smaller pieces
and adds a header to form a TCP segment. On the other hand, UDP does not support
segmentation, so the applications using UDP should send messages
short enough to fit into one UDP datagram. Note that the data unit in TCP is called
TCP segment, and the data unit in UDP is called UDP datagram.
UDP datagrams are considered unreliable because there is no guarantee that all datagrams sent
will be received in the destination and in the correct order. So, if reliability is needed,
UDP should not be used. UDP lacks error checking and
correction. It makes UDP fast and efficient for DNS, DHCP, SNMP, and RIP protocols.
UDP is also suited for streaming videos. When the application layer invokes the UDP
protocol, UDP encapsulates the application message into UDP datagrams. The datagram is then
passed to the network layer for transmission. At the receiving end, the network layer sends
the UDP datagram to the transport layer. UDP then extracts the application message from the datagram
and passes it to the application layer. TCP, on the other hand, is reliable and
guarantees in-order delivery of data from the sender to the receiver. The data transmission
via TCP has three phases: · Connection establishment
· Data transfer, and · Connection termination
In the Connection Establishment phase, the sender TCP or client sends a packet to the receiver TCP
or server requesting a connection. The server then sends an acknowledgement to the client. The client
further acknowledges the server. It completes the process of connection establishment. Since a
connection is set up before data transmission, TCP is a connection-oriented protocol,
and the connection establishment process is called Three-Way TCP Connection Handshake.
Once the connection is established, the next phase is the Data Transfer.
During data transfer, TCP offers some key features which UDP does not provide, and it includes
• Error-free data transfer • Ordered-data transfer
• Retransmission of lost data • Discarding duplicate packets, and
• Congestion throttling Let us discuss each feature one-by-one.
Error-Free Data Transfer is provided by using the field Checksum. The sender calculates and
enters a value in this field. At the receiving end, the receiver performs the same process
and calculates the checksum value. If it does not match with the value present in the checksum
field, the TCP segment is discarded, and no ACK is sent to the sender. Because the sending
side does not receive an acknowledgement of the discarded packet, it is retransmitted.
Ordered-Data Transfer TCP adds a sequence number in the TCP segments.
At the receiving end, the TCP module uses the sequence numbers to reconstruct the application
message in the correct order. Retransmission of Lost segments
For reliable data transfer, the receiver TCP sends an acknowledgement to the sender TCP for each TCP
segment it receives. If an acknowledgement is not received, the TCP segment is retransmitted.
Therefore, if a TCP segment is lost, the receiver will not send an ACK message to the sender.
As a result, the sender TCP sends the lost segment again.
Discarding Duplicate segments The TCP client retransmits packets that
it determines to be lost. However, the receiver TCP may receive segments that were considered to
be lost after the sending side has retransmitted the segments. As a result, the receiving end will
have two or more copies of the same segment. In such cases, the unique sequence numbers in the TCP
header of every segment helps to determine the duplicate segments, which are then discarded.
Congestion Throttling or flow control The goal for TCP is to send segments to
the receiving end as fast as possible without losing them. When TCP first sends the segments,
it sets a timer. If the segments are acknowledged before the timer expires, TCP increases the
transmission speed until the segments begin to become unacknowledged. Since the ACK for some
segments is not received within the time, the sending TCP module retransmits the segments.
When a significant number of packets have to be retransmitted, TCP slows down the
data transfer rate. In this way, TCP handles congestion throttling or flow control.
The last phase in the data transmission is Connection Termination.
When an endpoint wishes to stop its connection, it sends a finished message to the other endpoint.
The other end acknowledges the message. Both ends do this two-phase handshake process.
Therefore, the connection termination follows a four-way handshake process.
The Top Most Layer in the TCP/IP protocol suite is the
Application layer
The application layer is used by user applications that pass messages from one computer to another in
layer protocols to perform their activities. For example, web browsers use HTTP
or HTTPS – to do web surfing. Email programs, such as Microsoft Outlook, use
post office protocol (POP) or the Simple Mail Transfer Protocol (SMTP) for transferring emails.
So, the application layer provides means to access information on the network.
This is a list of protocols provided by the application layer
DNS - Domain Name System translates IP addresses into Domain Names and vice-versa.
DHCP - Dynamic Host Configuration Protocol automatically assign IP addresses to
computers present in the network. FTP - File Transfer Protocol is used
to transfer files on the Internet HTTP - HyperText Transfer Protocol
is used for sending and receiving webpages IMAP - Internet Message Access Protocol is used
for email messages on the Internet IRC - Internet Relay Chat protocol
is used for Internet chat. POP3 - Post Office Protocol
Version 3 is used by email clients to retrieve messages from remote servers
SMTP - Simple Mail Transfer Protocol is used for email messages on the Internet
It completes the TCP/IP protocol suite. If you have learnt something from this video, then
please like this video. Share this video so that more people can learn. Thanks for watching.
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