Table of Contents

Link Layer Discovery Protocol (LLDP): What is it used for?

LLDP (Link Layer Discovery Protocol) is a popular networking protocol used to discover and collect information from other nearby devices. It's an essential tool for any network administrator, as it provides a direct line of communication between two systems over the same local area network segment (LAN). If you're interested in gaining more insight into how this protocol works, then continue reading to learn more about the LLDP protocol and its primary uses.

So Let's Get Started: What Is LLDP Protocol and What Is It Used For?

LLDP (Link Layer Discovery Protocol) is a network protocol that allows network devices to advertise their identity and capabilities on a local area network. This enables other devices on the network to discover information about their neighbors, such as the device's type, manufacturer, and capabilities. LLDP protocol is a standards-based protocol, which means it is designed to work with various network devices from different manufacturers. Using LLDP, network administrators can easily see what devices are connected to the network and their capabilities without manually configuring each device. This can save a lot of time and effort when setting up or maintaining a network.

LLDP protocol is often used in conjunction with other network protocols, such as Spanning Tree Protocol (STP) and VLAN tagging, to help manage and control a network. For example, STP can use information from LLDP frames to determine the best path for network traffic. In contrast, VLAN tagging can use LLDP information to automatically assign devices to the correct VLAN. This allows for efficient and automated management of large networks.

LLDP is a valuable protocol for network administrators, as it provides a simple and effective way to discover information about the devices on a network. By using the LLDP protocol, network administrators can quickly and easily see what devices are connected to the network, what their capabilities are, and how they are connected. This information can be used to optimize network performance, troubleshoot problems, and ensure that the network is running smoothly.

How Does It Work?

LLDP works by sending out periodic messages, called LLDP frames, which contain information about the device that is sending them. The protocol uses a management information base (MIB) to define the information exchanged between devices, which is typically accessed using the Simple Network Management Protocol (SNMP).

When a device sends out an LLDP frame, it includes information from its MIB, such as the device's type, manufacturer, and capabilities. Other devices on the network can receive and process these frames to gather information about their neighbors. This information is stored in a database on each device, which can then be accessed using SNMP to view and manage the network.

SNMP allows network administrators to access and manipulate the information in a device's MIB using a set of standardized commands. This makes it easy to monitor the performance of network devices, troubleshoot problems, and configure the network.

In short, LLDP protocol and SNMP work together to provide a simple and effective way for network devices to advertise their identity and capabilities and for other devices on the network to discover and manage this information. This allows for efficient and automated management of large networks.

CDP vs. LLDP: What Are the Differences?

CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol) are both protocols that allow network devices to advertise their identity and capabilities on a local area network. Both protocols are designed to work with a wide range of network devices from different manufacturers, and both can be used to gather information about the devices on a network.

One key difference between CDP and LLDP protocol is that CDP is proprietary to Cisco, while LLDP is an open standard. This means CDP is only supported on Cisco devices, while LLDP is supported on a wider range of devices from different manufacturers. This can make LLDP more flexible and interoperable than CDP in some cases.

Another key difference is the type of information that is exchanged between devices. CDP typically provides more detailed information about a device's capabilities, such as its IOS version and IP address. LLDP protocol provides less detailed information but is standardized across different manufacturers, making it easier to process and use.

Overall, both CDP and LLDP can be useful for network administrators, as they provide a way to discover information about the devices on a network. The choice between the two protocols will depend on the specific needs and requirements of the network.

Common Use Cases for LLDP Protocol:

Some common use cases for LLDP protocol include:

  1. Automatically assigning devices to VLANs: LLDP information can automatically assign devices to the correct VLAN based on their type and capabilities. This can make managing and controlling network traffic on large networks easier.
  2. Determining the best path for network traffic: Network protocols like STP can use LLDP information to determine the best path for network traffic based on the devices and connections on the network.
  3. Troubleshooting network problems: LLDP information can be used to help identify the source of network problems, such as connectivity issues or slow performance.
  4. Inventory management: Network administrators can use LLDP information to keep track of the devices on a network, including their type, manufacturer, and capabilities. This can be useful for inventory management and planning.
  5. Monitoring network performance: LLDP information can be used to monitor the performance of network devices and connections and to identify potential bottlenecks or other issues that may need to be addressed.

LLDP-MED: An Enchanted Version of LLDP

LLDP-MED (Media Endpoint Discovery) is an extension to the LLDP (Link Layer Discovery Protocol) that is specifically designed for use in voice-over IP (VoIP) networks. LLDP-MED provides a way for network devices to advertise their identity and capabilities and information specific to VoIP, such as the device's power source, Quality of Service (QoS) settings, and VLAN assignment.

LLDP-MED is based on the same principles as LLDP and uses the same MIB and SNMP standards for exchanging information. However, LLDP-MED defines a specific set of MIB objects that are relevant to VoIP networks, such as the device's power source, VLAN assignment, and QoS settings. This allows network devices to advertise this information to their neighbors and for other devices on the network to discover and use it.

LLDP-MED is often used with other network protocols, such as VLAN tagging and QoS, to help manage and control a VoIP network. By using LLDP-MED, network administrators can easily see what devices are connected to the network, what their capabilities are, and how they are connected. This can help optimize network performance and ensure that VoIP calls are delivered reliably and with high quality.

Final Words

To learn more about how LLDP protocol works and how you can use it in your own projects, check out our online courses at orhanergun.net. We provide comprehensive training on all networking aspects, from basic concepts to advanced techniques. With our help, you’ll be able to put LLDP protocol to work in your business and see improved performance and efficiency across your entire network.

Created by
Stanley Avery

I am a certified network engineer with over 10 years of experience in the field. I have a deep understanding of networking and IT security, and I am always looking for new challenges.

View profile