OSI Physical Layer: http://learn-networking.com/network- design/the-difference-between-straight-through- crossover-and-rollover-cables The Physical Layer is the copper, fiber, or wireless that connects network devices. The bits that arrive here are encoded according to the protocols that govern their type of end device. The control code is added to indicate the beginning and ending of each frame of bits. The encoded bits are transformed into signals (voltage, light, or radio waves) and sent to the destination device.
The Physical Layer is the copper, fiber, or wireless that connects network devices. The bits that arrive here are encoded according to the protocols that govern their type of end device. The control code is added to indicate the beginning and ending of each frame of bits. The encoded bits are transformed into signals (voltage, light, or radio waves) and sent to the destination device.
The Data-Link layer arranges the bits it receives into frames and provides synchronization, error control and flow control. It has two sub layers that are the logical link control and media access control. It begins the process of encapsulation and adds a trailer and header. The source and destination addresses are included along with frame check sequence values, quality of service, and type of protocol for whatever media is present. It links the hardware and software layers together.
Network Layer
Translates addresses from logical to physical and visa-versa the other way. This is where addressing the networks and subnetting comes into play.
Encapsulation of frames: IP header, source IP address, destination IP address.
All available common network layer protocols.
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Type of service determines the priority of the packet and looks for the Quality of Service to decide who goes first. EX: Voice transmits faster than e-mail.Time to Live ensures a packet can’t get stuck looping in to infinity.Protocol determines which type of data packet it is: ICMP, TCP, UDPThe header checksum provides a security measure to make sure the data is exactly how it was from origination to destination.Packet Length is between
Routing:
Carrying Data end to end:
Transport Layer: Visual Version
Source Port Address or name of remote host
destination PortConnection State
The top three layers
Application Layer: Is the first step to getting data onto the network.
Three primary functions:1. Coding and conversion of application layer data to
ensure that data from the source device can be interpreted by the appropriate application on the destination device.
2. Compression of the data so that it can be decompressed by the destination device.
3. Encryption of the data for transmission and decryption of data by the destination device.
Applications are computer programs with which the user interacts and that initiate the data transfer process at the user’s request.Services are background programs that provide the connection between the application layer and the lower layers of the networking model.
The most widely-known TCP/IP Application layer protocols are those that provide for the exchange of user information. These protocols specify the format and control information necessary for many of the common Internet communication functions. Among these TCP/IP protocols are:
