Networking Fundamentals: Models, Protocols, and Topologies

Core Networking Concepts Summarized

Here are short notes on four fundamental topics in computer networking:

  1. OSI Model: The Open Systems Interconnection (OSI) model is a conceptual framework that standardizes network communication into seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. It aids in understanding and troubleshooting network protocols.
  2. TCP/IP Model: The Transmission Control Protocol/Internet Protocol (TCP/IP) model is a practical networking model
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Python Code Snippets for Data Science and AI

# **Program 1:

NumPy

Array Operations**
import numpy as np
arr=np.Array([[1,2,3],[4,5,6],[7,8,9]])
print(“Sum of all columns:”,np.
sum(arr,axis=0))
print(“Product of all rows:”,np.Prod(arr,axis=1))
print(“Last two rows and columns:\n”,arr[1:,1:])
arr2=np.Array([[9,8,7],[6,5,4],[3,2,1]])
print(“Element-wise addition:\n”,arr+arr2)
.
.

# **Program 2: Vowel Frequency in Each Word**
sentence=input(“Enter a sentence in lowercase: “)
vowels=’aeiou’
for w in sentence.Split():
    print(f”{w}: {sum(w.Count(v) for v in

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Java Implementation of DSS Signing and Cipher Cryptanalysis

Digital Signature Standard (DSS) Client Implementation

This Java class, DssClient, demonstrates the generation of a Digital Signature Standard (DSS) signature and subsequent transmission of the parameters to a verification server via a socket connection.

1.1. DssClient Class Structure and Signature Generation

The dssSign method calculates the signature components r and s, along with the public key y, based on input parameters (primes p, q, generator g, private key x, message hash H(m), and random nonce

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Artificial Intelligence Search Algorithms and Agent Fundamentals

AI Agents and Architecture

Agents perceive their environment using sensors and act rationally upon that environment using effectors.

Agent Architecture

Agent → Actions (with effectors) → Environment → Percepts → Agent

Key Agent Features

  • Situatness: The agent’s direct connection to its environment through percepts and effectors.
  • Autonomy: The agent acts without intervention by humans or other agents. (Preprogramming does not count.)
  • Adaptivity: The ability to react flexibly to changes in its environment.
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Wireless Communication Protocols and Mobile Network Architecture

Wireless Application Protocol (WAP) Fundamentals

WAP (Wireless Application Protocol) is a set of protocols designed for wireless devices (like mobile phones and PDAs) to access internet services. It uses a client-server model, with the mobile device acting as the client and a WAP gateway/web server as the server. WAP optimizes content for low bandwidth, small screens, and limited processing power.

WAP Protocol Stack Layers

The WAP model is structured into several distinct layers:

  • Application Layer:
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Digital Modulation Techniques in Python: Pulse Shaping and QPSK

import numpy as np

T = 1 #time period

Fs = 100 #sampling frequency

t = np.
arange(-3*T, 3*T, 1/Fs)

g = lambda t: np.Sinc(t) * np.Cos(np.Pi*0.5*t) / (1-(2*0.5*t)**2) #Defining a lambda function g(t) that represents a raised cosine filter with a roll-off factor of 0.5.

plt.
Figure(figsize=(8,3))

plt.Plot(t, g(t))

binary_sequence = np.Array(np.Random.Randint(2,size=50))

d = 2 * np.Array(binary_sequence) – 1 #making the binary sequence NRZ

def get_signal(d): #to get transmitted signal

    t = np.Arange(-2*T,

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