Back to Networking Essential Course Part-1
Networking Essential Notes – Section 2
How a Network Functions
The 802 Project Model
- Defines Standard for the Data Link and Physical Layers.
- Network Adapter Cards (NAC)
- WAN Components
- Component used to create twisted-pair and coaxial cable networks.
- A crazy mnemonic for this table, but it works
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OSI Model Enhancements
The bottom two Layers – Data Link and Physical – define how multiple computers can simultaneously use the network without interfering with each other.
- Divided the Data-Link layer into the Logical Link Control and Media Access Control Sublayers.
- Logical Link Control
a. Manages error and flow control
b. Defines logical interface point called Service Access Points (SAP’s). These SAP’s are used to transfer information to upper layers
- Media Access Control
a. Communicates directly with the network adapter card and
b. is responsible for delivering error-free data between two computers
3. 802.5 and
4. 802.12 define standards for both this sublayer and the physical layer
- A device driver is software that tells the computer how to drive or work with the device so that the device performs the job it’s supposed to.
- Drivers are called
- Provide communication between a network adapter card and the redirector in the computer.
- Resides in the Media Access Control sublayer of the Data Link layer. Therefore, the NIC driver ensures direct communication between the computer and the NIC
- the Media Access Control driver is another name for the network card device driver
- When installing a driver, you need to know these things
- I/O Port Address
- Memory Mapped (Base Memory Address)
- Data is broken down into smaller more manageable pieces called packets.
- Special control information is added in order to:
- disassemble packets
- reassemble packets
- check for errors
Types of Data Sent Includes
- Can contain information such as messages or files.
- Computer control data and commands and requests.
- Session control codes such as error correction and re-transmission requests
- Original block of data is converted to a packet at the Transport layer.