Untitled Quiz

Network Characteristics and Introduction

• Purpose: enables end devices to exchange data
• Protocols: IPv4 and IPv6 are primary communication protocols
• Basic Operations: addressing end devices, encapsulation, routing, de-encapsulation

IP Encapsulation

• IP encapsulates the transport layer segment
• Addressing remains unchanged throughout the journey

Connectionless Nature of IP

• No connection established prior to sending packets
• IP does not require control information
• Best Effort Delivery: no guarantee of packet delivery, reduces overhead, no resending of lost packets

Media Independence

• IP operates independently of media types (copper, fiber, wireless)
• Works without concern for data link layer frames

Maximum Transmission Unit (MTU)

• Established by the network layer based on data link layer control information

IPv4 Packet Header

• Purpose: directs packets to correct destinations and processes for routing
• Fields include Source/Destination IPv4 addresses, Version, TTL (Time-To-Live)
• Version: 4 for IPv4
• Total Length: Size of packet including header
• Protocol: Identifies next level protocol (TCP, UDP, etc.)

IPv6 Overview

• Limitations of IPv4: address depletion, end-to-end connectivity issues, increased network complexity caused by NAT usage
• Benefits of IPv6: large address space (128 bits), improved packet handling, no need for NAT, facilitates direct communication

IPv6 Packet Header Fields

• Simplified header includes fewer fields
• Significant fields similar to IPv4 with enhancements

Host Routing Decisions

• Packets created at the source device
• Host maintains its routing table for local, LAN, and remote destinations
• Default gateway is required for routing outside the local network

Packet Routing Basics

• Fragmentation occurs when IPv4 packets are split for transmission

Routing Table Types

• Directly Connected: Automatically added by active interfaces
• Remote: Learned through static or dynamic routing
• Default Route: Used when no matching route is found

Static vs Dynamic Routes

• Static Routes: Manually configured, adjusted during topology changes
• Dynamic Routes: Automatically discover and maintain routing information

Module 9: Address Resolution

• Devices use MAC addresses for Layer 2 communication
• IP addresses (Layer 3) are used for routing packets between different networks
• Address Resolution Protocol (ARP): maps IPv4 addresses to MAC addresses, resolves local or gateway MAC addresses for communication
• ARP Vulnerabilities: ARP spoofing can cause security threats like ARP poisoning

IPv6 Neighbor Discovery Protocol

• Replaces ARP in IPv6
• Uses ICMPv6 messages like Neighbor Solicitation (NS) and Neighbor Advertisement (NA)

Module 10: Basic Router Configuration

• Initial Router Settings: set hostname, secure access (password), configure banners, save configuration to NVRAM
• Interface Configuration: assign IP addresses, activate interfaces with no shutdown
• Verification Commands: show ip interface brief, show ipv6 interface brief, show ip route, show ipv6 route

Module 11: IPv4 Addressing

• IPv4 Structure: composed of network and host portion defined by a subnet mask, logical ANDing is used to determine network addresses
• Address Types:
  • Unicast: one-to-one communication
  • Broadcast: one-to-all on the same network
  • Multicast: one-to-many group addresses
• Subnetting: divides networks into smaller, efficient subnets using CIDR and VLSM techniques

Module 12: IPv6 Addressing

• IPv6 Basics: 128-bit address space, represented in hexadecimal, supports larger address spaces and better security than IPv4
• Address Types:
  • Unicast: unique to a single device
  • Multicast: communicates to multiple devices
  • Anycast: routes to the nearest device
• Dynamic Addressing: methods like SLAAC, stateless DHCPv6, and stateful DHCPv6
• Subnetting in IPv6: uses a 16-bit subnet ID field between the Global Routing Prefix and Interface ID, subnet IDs allow efficient allocation and management

Module 13: ICMP Messages and Connectivity Tests

• ICMP Overview: provides error messaging and operational checks (IPv4 and IPv6)
• Key messages: echo (ping), destination unreachable, time exceeded
• Ping and Traceroute Tests: tests connectivity, identifies the path and routers

Module 14: Transport Layer

• TCP and UDP:
  • TCP: reliable, stateful, ensures data order with features like retransmissions and flow control
  • UDP: lightweight, connectionless, suitable for latency-sensitive applications

Module 15: Application, Presentation, and Session Layers

• Key Application Layer Protocols: HTTP, FTP, SMTP, DNS, DHCP, IMAP
• Presentation Layer: formats, compresses, and encrypts data
• Session Layer: manages dialog creation and maintenance
• P2P Networks and Applications: facilitates decentralized resource sharing

Module 16: Network Security Fundamentals

• Threats: physical damage, environmental issues, malware (viruses, worms, ransomware), access attacks (password cracking), DoS/DDoS
• Mitigation Strategies: defense-in-depth, backups and updates, AAA (Authentication, Authorization, and Accounting), endpoint security

Module 17: Small Network Management

• Network Design: redundancy, traffic management (QoS), scaling considerations, connectivity verification