Sherif Mohamed Saber (Layer 2 vs Layer 3).pptx

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1. Data Link Layer (2) vs Network Layer (3)

2. Layer 2 (Data Link Layer) The Data Link Layer is the second layer in the OSI (Open Systems Interconnection) model and is responsible for node-to-node data transfer between two directly connected nodes. OSI Model (Data Link Layer )

3. Functions of the Data Link Layer (Layer 2) Functions Framing : It breaks the data received from the Network Layer into frames and ensures that the message is delivered without any errors. Error Control : It provides error detection and correction mechanisms to ensure that data is transferred accurately. Flow Control : It manages the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Physical Addressing : It handles the addressing of devices using MAC (Media Access Control) addresses to ensure that data is delivered to the correct device on a network. Access Control : It determines which device has control over the communication channel at any given time.

4. Addressing / Error Detection and Correction Addressing MAC Address : A unique identifier assigned to network interfaces for communications on the physical network segment. It consists of 48 bits and is usually represented as a sequence of 12 hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E). Error Detection and Correction Cyclic Redundancy Check (CRC) : A method used to detect errors in transmitted frames. Acknowledgements and Retransmissions : Mechanisms to ensure that frames are delivered reliably.

5. Network Layer (Layer 3) The Network Layer is the third layer in the OSI (Open Systems Interconnection) model and is responsible for the delivery of packets between devices across different networks. It manages the routing of data from the source to the destination through intermediate routers and is essential for internetworking.

6. Network Layer

7. OSI Model

8. Functions of Network Layer Functions Routing : Determines the best path for data to travel from the source to the destination across multiple networks. Logical Addressing : Uses IP addresses to identify devices on a network and ensures that data is sent to the correct destination. Packet Forwarding : Moves packets from the source to the destination based on the routing table. Fragmentation and Reassembly : Splits large packets into smaller ones for transmission and reassembles them at the destination. Error Handling and Diagnostics : Provides mechanisms for detecting and reporting errors in data delivery.

9. Key Concepts IP Addressing : The Network Layer uses IP (Internet Protocol) addresses to identify devices on a network. IPv4 addresses are 32 bits long, while IPv6 addresses are 128 bits long. Subnets : Networks are divided into smaller sub-networks (subnets) to manage and optimize routing. Routing Table : Contains information about the routes to different network destinations, which helps routers make forwarding decisions. Packet Switching : Data is broken into packets that are sent independently over the network and reassembled at the destination.

10. Protocols Several protocols operate at the Network Layer, including: IPv4 (Internet Protocol version 4) : The most widely used protocol for addressing and routing data packets. IPv6 (Internet Protocol version 6) : The successor to IPv4, designed to address the limitations of IPv4, such as the limited address space. ICMP (Internet Control Message Protocol) : Used for error messages and operational information queries. IGMP (Internet Group Management Protocol) : Manages the membership of IP multicast groups. IPsec (Internet Protocol Security) : Provides security for IP communications by authenticating and encrypting each IP packet.