CCNA Cisco Netacad: Introduction to Networks - Build a Small Network (Module 17)

Overview

• Objective: Implement a network design for a small network using a router, a switch, and end devices.
• Focus: Devices in the small network, network applications and protocols, scaling networks, verifying connectivity, host and ISO commands, and troubleshooting methodologies.

Small Network Topologies

• Design: Simple, typically with a single WAN connection (DSL, cable, or Ethernet).
• Management: Often by a local IT technician or contracted professional.

Device Selection for Small Networks

• Considerations: Cost, speed, types of ports/interfaces, expandability, OS features.
• Example: High-speed internal networks for engineering offices may use fiber optics, while accounting may use Cat5 cables.

Implementing a Network

• IP Addressing Scheme: Unique addresses for all devices.
• VLSM (Variable Length Subnet Mask): Important for efficient IP allocation.

Redundancy

• Importance: Eliminates single points of failure.
• Methods: Duplicate equipment and network links.

Traffic Management

• QoS (Quality of Service): Important for real-time traffic like voice and video.
• Priority Queuing: Ensures high-priority traffic (e.g., voice) is processed first.

Small Network Applications and Protocols

• Common Applications: Network applications and application layer services.
• Common Protocols: Telnet, SSH, HTTP/HTTPS, SMTP, POP3, IMAP, FTP/SFTP, DHCP, DNS.

Scaling Small Networks

• Growth: Requires documentation, inventory, budget, and traffic analysis.
• Traffic Flow Monitoring: Essential for understanding and managing network traffic efficiently.

Verify Connectivity

• Ping Command: Tests layer 3 connectivity using ICMP.
• Extended Ping: Allows parameter adjustments.
• Trace Route: Identifies where connectivity issues occur in a network.

Network Baseline

• Importance: Helps in monitoring and troubleshooting network performance.
• Method: Save results from ping, trace route, etc., and compare over time.

IP Configuration on Hosts

• Windows: Ipconfig, ipconfig /all, /release, /renew, /displaydns.
• Linux: ifconfig, ip address.
• Mac: Network preferences, ifconfig, networksetup commands.

ARP Command

• Function: Lists devices in ARP cache.
• Command: arp -a (Windows).

Common iOS Commands

• Commands: show running-config, show interfaces, show ip interface, show arp, show ip route, show protocols, show version.

Troubleshooting Methodologies

• Steps:
  1. Identify the problem.
  2. Establish a theory of probable causes.
  3. Test the theory.
  4. Establish a plan of action.
  5. Verify solution and implement preventive measures.
  6. Document findings.

Debugging in iOS

• Use: Display messages in real time for analysis.
• Caution: Debugging can overload system resources.

Troubleshooting Scenarios

• Duplex Mismatch: Causes performance issues.
• IP Addressing Issues: Manual mistakes or DHCP problems.
• Default Gateway and DNS Issues: Can cause network communication failures.

Final Thoughts

• Preparation for Exams: Review all modules and labs thoroughly.
• Resources: Utilize Cisco Netacad labs and practice scenarios where possible.