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

Lecture Overview

• This lecture focuses on implementing a network design for a small network.
• Key points include:
  • Devices in a small network (router, switch, end devices)
  • Small network applications and protocols
  • Scaling small networks to larger ones
  • Verifying connectivity
  • Host and ISO commands
  • Troubleshooting methodologies and scenarios
• This is the final lecture in the ITN course.

Key Concepts

Small Network Topologies

• Small networks are simple, often with a single WAN connection (DSL, cable, or Ethernet).
• Managed by a local IT technician or contracted out.
• Small network design considerations:
  • Cost, speed, port types, expandability, OS features
  • High-speed internal networks may use fiber optics for large files.

Network Planning

• Importance of planning: addresses requirements, cost, and deployment options.
• Device selection factors: cost and user needs.
• Example: High-speed needs (fiber optics) for engineering vs. basic needs (Cat5 cable) for accounting.
• IP Addressing: Unique addresses for all devices. Use VLSM and subnetting.
• Redundancy: Provides reliability by eliminating single failure points.

Traffic Management

• Use of QoS to prioritize traffic (e.g., voice and video).
• Implement quality of service to manage traffic efficiently.

Applications and Protocols

Common Network Applications

• Network applications and application layer services are essential.
• Common protocols:
  • Remote access: Telnet, SSH
  • Web: HTTP, HTTPS
  • Email: SMTP, POP3, IMAP
  • File Transfer: FTP, SFTP
  • Dynamic IP: DHCP
  • DNS: Resolves domain names

Real-time Applications

• Use of IP telephony and streaming media for remote work.
• Network requirements for supporting real-time applications (QoS, RTP, RTCP).

Scaling to Larger Networks

• Network growth aligned with business growth.
• Key elements:
  • Network documentation
  • Device inventory
  • Budget
  • Traffic analysis
• Capture traffic during peak times for accurate analysis.
• Use protocol analyzers to evaluate source, destination, and type of traffic.

Verifying Connectivity

Ping Command

• Verifies Layer 3 connectivity using ICMP (types 8 and 0).
• Default ping settings:
  • Windows: 4 ICMP messages
  • Cisco IOS: 5 ICMP messages

Traceroute Command

• Identifies path and problem areas in connectivity.
• Command syntax differs between operating systems (e.g., tracert on Windows, traceroute on iOS).
• Extended traceroute allows parameter adjustments.

Network Baseline

• Create baselines by recording ping, traceroute, and other command outputs.
• Baseline helps in monitoring and troubleshooting network performance.

Host Configuration Commands

Windows

• Use ipconfig, ipconfig /all, ipconfig /release, ipconfig /renew, ipconfig /displaydns.

Linux

• Use ifconfig, ip address, ip -a.

Mac

• Use ifconfig and network setup commands.
• GUI access through Network Preferences.

ARP Commands

• ARP -A to list current ARP cache.
• Clear ARP cache with netsh interface ip delete arpcache.

IOS Commands

Common Commands

• show running-config
• show interfaces
• show ip interface brief
• show arp
• show ip route
• show protocols
• show version

CDP Neighbors

• Use show cdp neighbors for device info.

Troubleshooting Methodologies

Basic Steps

1. Identify the problem
2. Establish a theory of probable causes
3. Test the theory to determine the cause
4. Establish a plan of action and implement a solution
5. Verify solution and implement preventive measures
6. Document findings and outcomes

Common Issues

• Duplex mismatches
• IP addressing errors
• Default gateway and DNS issues

Conclusion

• This lecture caps off the course by integrating all previous modules.
• Emphasis on planning, documenting, verifying, and troubleshooting small networks.
• Upcoming lecture series and additional resources are available for students.