Free CCNA | CDP & LLDP | Day 36 | CCNA 200-301 Complete Course

Introduction

In this tutorial, we will explore Layer 2 discovery protocols, specifically the Cisco Discovery Protocol (CDP) and the Link Layer Discovery Protocol (LLDP). These protocols are essential for network management, allowing devices to discover information about directly connected devices. This guide is based on Day 36 of Jeremy's IT Lab's free CCNA 200-301 complete course, providing practical steps for configuration and verification of CDP and LLDP.

Step 1: Understand Layer 2 Discovery Protocols

• Layer 2 discovery protocols allow network devices to communicate information about themselves and their capabilities.
• The two primary protocols discussed are:
  • CDP: Cisco proprietary protocol.
  • LLDP: Open standard protocol supported by multiple vendors.

Step 2: Learn About CDP

Introduction to CDP

• CDP enables Cisco devices to share information such as device ID, IP address, and capabilities.
• It operates at Layer 2 of the OSI model and does not require IP configuration.

Verification of CDP

1. Use the command show cdp neighbors to view directly connected devices.
2. For detailed information, use show cdp neighbors detail.

Configuration of CDP

1. Access the device's command line interface (CLI).
2. Enter global configuration mode:

   configure terminal
   

3. Enable CDP:

   cdp run
   

Step 3: Learn About LLDP

Introduction to LLDP

• LLDP is an industry-standard protocol that provides similar functionality as CDP but is vendor-agnostic.
• It allows devices to advertise themselves and their capabilities.

Configuration of LLDP

1. Access the device's CLI.
2. Enter global configuration mode:

   configure terminal
   

3. Enable LLDP:

   lldp run
   

Verification of LLDP

1. Use the command show lldp neighbors to list neighboring devices.
2. For detailed information, use show lldp neighbors detail.

Step 4: Analyze Protocols Using Wireshark

• Wireshark can capture and analyze CDP and LLDP packets for deeper insights.
• To capture packets:
  1. Start Wireshark.
  2. Select the appropriate network interface.
  3. Use filters to focus on CDP and LLDP packets:
     • For CDP: cdp
     • For LLDP: lldp

Conclusion

In this tutorial, we covered the fundamentals of CDP and LLDP, including their configuration and verification. Understanding these protocols is crucial for effective network management and troubleshooting. Next steps may include hands-on practice in a lab environment or further study of network management protocols in preparation for the CCNA exam.