In addition to specific protocols, important general topics such as redistribution, default routes and on- demand routing, route filtering, and route maps are covered.
Data link layer 1. This layer includes applications or processes that use transport layer protocols to deliver the data to destination computers.
At each layer there are certain protocol options to carry out the task designated to that particular layer. So, application layer also has various protocols that applications use to communicate with the second layer, the transport layer.
Some of the popular application layer protocols are: Transport Layer This layer provides backbone to data flow between two hosts. This layer receives data from the application layer above it. There are many protocols that work at this layer but the two most commonly used protocols at transport layer are TCP and UDP.
TCP is used where a reliable connection is required while UDP is used in case of unreliable connections. TCP divides the data coming from the application layer into proper sized chunks and then passes these chunks onto the network. So, the protocol used for this type of connection must provide the mechanism to achieve this desired characteristic.
For example, while downloading a file, it is not desired to loose any information bytes as it may lead to corruption of downloaded content.
UDP provides a comparatively simpler but unreliable service by sending packets from one host to another. UDP does not take any extra measures to ensure that the data sent is received by the target host or not.
For example while streaming a video, loss of few bytes of information due to some reason is acceptable as this does not harm the user experience much. Network Layer This layer is also known as Internet layer.
The main purpose of this layer is to organize or handle the movement of data on network. By movement of data, we generally mean routing of data over the network. The main protocol used at this layer is IP. Data Link Layer This layer is also known as network interface layer.
This layer normally consists of device drivers in the OS and the network interface card attached to the system. Both the device drivers and the network interface card take care of the communication details with the media being used to transfer the data over the network.
In most of the cases, this media is in the form of cables. Client requests for a service while the server processes the request for client. Now, since we have discussed the underlying layers which help that data flow from host to target over a network.
Lets take a very simple example to make the concept more clear. Consider the data flow when you open a website.
As seen in the above figure, the information flows downward through each layer on the host machine. At the first layer, since http protocol is being used, so an HTTP request is formed and sent to the transport layer.
Here the protocol TCP assigns some more information like sequence number, source port number, destination port number etc to the data coming from upper layer so that the communication remains reliable i.
At the next lower layer, IP adds its own information over the data coming from transport layer. This information would help in packet travelling over the network.
Here again the communication done at the data link layer can be reliable or unreliable. This information travels on the physical media like Ethernet and reaches the target machine. Now, at the target machine which in our case is the machine at which the website is hosted the same series of interactions happen, but in reverse order.
The packet is first received at the data link layer. At this layer the information that was stuffed by the data link layer protocol of the host machine is read and rest of the data is passed to the upper layer. Similarly at the Network layer, the information set by the Network layer protocol of host machine is read and rest of the information is passed on the next upper layer.
Same happens at the transport layer and finally the HTTP request sent by the host application your browser is received by the target application Website server. One would wonder what happens when information particular to each layer is read by the corresponding protocols at target machine or why is it required?
Well, lets understand this by an example of TCP protocol present at transport layer. At the host machine this protocol adds information like sequence number to each packet sent by this layer.
Now, if the host TCP does not receive the acknowledgement within some specified time, it re sends the same packet.
So this way TCP makes sure that no packet gets lost.Jan 28, · As the packets go up to the destination, then layer 1 is the physical data, 2 is the MAC of the eventual destination, Layer 3 is the same destination IP as picked at the beginning (remember that MAC addresses change hop to hop, IP addresses do not).
So, if a TCP/IP address needs to comunicate with another, is just uses the TCP/IP address. But the network devices need to know to which network card that message is going, so they, somehow, translate the TCP/IP address with to the MAC address. Organ Sales: Legalize for the Greater Good Every day, numerous people across the world stop their lives for four hours to get hooked up to a dialysis machine at a hospital arteensevilla.com machine helps to remove harmful wastes, toxins, excess salt, and water from their body because unfortunately their body cannot do so .
Yesterday, after receiving the question that every parent is afraid of, I spent 40 minutes explaining the answer to my 4 year old daughter Nathalie, the answer to .
Transmission Control Protocol (TCP) and Internet Protocol (IP) are the two main protocols that the internet uses. A protocol is a rule that governs how data moves through the internet and how network connections are established and terminated. Chapter 5 Planning Your TCP/IP Network.
This chapter describes the issues you must resolve in order to create your network in an organized, cost-effective manner.