Transport Layer Functions: TCP vs UDP Explained
The Transport Layer is the fourth layer of the OSI Model and plays a vital role in providing end-to-end communication between source and destination systems. It ensures that data is delivered reliably, accurately, and in the correct sequence.
Core Functions of the Transport Layer
- Segmentation and Reassembly: Large messages are divided into smaller units called segments and reassembled at the receiver’s end.
- Flow Control: Regulates the speed of data transmission so the receiving device is not overwhelmed.
Computer Networking Fundamentals: Protocols and Security
Unit 1: Basics and Topology
Computer Network
A computer network is a system of interconnected devices that communicate and share data using communication protocols.
Basic Terms
- Node: Any device connected in a network.
- Protocol: Rules for communication (e.g., TCP/IP, HTTP).
- IP Address: Unique number assigned to each device.
- DNS: Converts domain names into IP addresses.
- Firewall: Protects the network from unauthorized access.
Types of Networks
- PAN: Connects personal devices within a short range.
- LAN: Small area
Networking, Control Systems, DNS, and Cryptography Basics
IPv4 Header Structure
The IPv4 header is essential for routing packets across networks.
- Version: 4 bits (IP version 4)
- IHL: 4 bits (Header length in 32-bit words, min=5)
- TOS/DSCP: 8 bits (Type of service / QoS priority)
- Total Length: 16 bits (Header + Data, max 65535 bytes)
- Identification: 16 bits (Unique ID for fragmentation)
- Flags: 3 bits (DF: don’t fragment, MF: more fragments)
- Fragment Offset: 13 bits (Position of fragment in original datagram)
- TTL: 8 bits (Hop count limit; decremented at each router)
Computer Networks: Course Logistics and Core Concepts
Course Logistics and Structure
- Grading Breakdown: Quizzes (10%), Assignments (30%), Midterm (25%), Final (35%).
- Pass Requirement: You must pass the Midterm and Final Exam in the aggregate (≥ 50%) to pass the course. If you miss the midterm with an official absence, the final exam weight shifts to 60%, and you must score at least 50% on the final to pass.
- Assignments: There are 3 programming assignments. You receive 4 total late days for the entire term, tracked daily (e.g., 1 minute late = 1 day
Computer Networking Fundamentals and OSI Model
Purpose of Layered Architecture
- Divides complex network tasks into layers
- Easier design and troubleshooting
- Standardization across vendors
- Independent development of layers
OSI Model Layers and Functions
- Physical Layer
- Transmits raw bits
- Deals with cables, voltage, and signals
- Data Link Layer
- Error detection
- Framing and MAC addressing
- Network Layer
- Logical addressing (IP)
- Routing of packets
- Transport Layer
- End-to-end delivery
- Error and flow control
- Session Layer
- Session establishment and termination
- Presentation Layer
- Data
Network Fundamentals: Protocols, Streaming, and Reliable Data Transfer
Core Networking Concepts
Circuit Switching Fundamentals
In circuit switching, first maximize the smallest link, then proceed to maximize the subsequent links.
Total Network Delay Components
Total delay is calculated as the sum of:
- Processing/Nodal Delay
- Queue Delay
- Transmission Delay (Trans)
- Propagation Delay (Prop)
Bandwidth-Delay Product (BDP)
The Bandwidth-Delay Product (BDP) represents how much data fits within the “pipe” (where delay is the length and bandwidth is the width). To find the number of pipes,
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