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Everything You Need To Know About LLDP and LLDP-MED Protocols

Everything You Need To Know About LLDP and LLDP-MED Protocols

As technology has advanced, so too have the protocols used to manage your networks. While most people are familiar with the more popular protocols like TCP/IP and BGP, there are also some lesser-known ones that can be incredibly useful for managing local area networks. One such protocol is Link Layer Discovery Protocol (LLDP). It was developed by the IEEE in 2005 and is used to allow devices on a network to advertise their capabilities, as well as automatically detect and configure connections between them. In addition to LLDP, there is also LLDP-MED (Media Endpoint Device), which adds additional features specifically related to VoIP phones, printers, and other media-related devices. In this blog post, we’ll take an in-depth look at both these protocols and how they can benefit you when managing your networks.

What are LLDP and LLDP-MED protocols?

LLDP and LLDP-MED are protocols that enable a network device to discover information about other devices on the same network. Devices that support these protocols can exchange information such as their device type, capabilities, and software version. This information helps ensure that devices are properly configured and allows administrators to troubleshoot problems more easily.

LLDP is an industry standard protocol, while LLDP-MED is an extension of LLDP that is specific to VoIP applications. Both protocols are supported by a wide range of networking equipment, including routers, switches, and IP phones.

In order for two devices to exchange information using LLDP or LLDP-MED, they must first be configured to do so. Once configuration is complete, the devices will periodically send out messages containing the requested information. These messages are typically sent every 30 seconds.

The Difference Between LLDP and LLDP-MED

LLDP and LLDP-MED are both network protocols that can be used to manage Ethernet networks. They each have their own advantages and disadvantages.

LLDP is a standards-based protocol that is widely supported by vendors. It is simple to configure and easy to use. However, it does not have any mechanisms for managing QoS or bandwidth constraints.

LLDP-MED is an extension of LLDP that adds support for managing QoS and bandwidth constraints. It is more complex to configure than LLDP, but it provides more granular control over the network.

How do LLDP and LLDP-MED Work?

The LLDP and LLDP-MED protocols work together to allow for the discovery and configuration of networked devices. LLDP is used to discover devices on the network, while LLDP-MED is used to configure those devices. Both protocols use a simple, standardized set of messages that are exchanged between devices.

LLDP begins with a device sending out an initial announcement, called an advertisement. This announcement contains information about the device, such as its capabilities and identity. Other devices on the network receive this advertisement and can use it to determine what type of device it is and how it can be configured.

LLDP-MED extends the functionality of LLDP by adding support for media-specific configuration parameters. These parameters are used to optimize the operation of audio and video applications on the network. For example, LLDP-MED can be used to configure Quality of Service (QoS) settings on switches and routers to ensure that voice and video traffic are given priority over other types of traffic.

Benefits of Using LLDP and LLDP-MED

LLDP and LLDP-MED are two industry-standard protocols that offer a number of benefits for networking professionals. Here are some of the key benefits of using these protocols:

  1. They simplify network management: LLDP and LLDP-MED make it easier to manage and configure networks, as they allow devices to be automatically discovered and configured.
  2. They improve network security: By allowing devices to be automatically identified and authenticated, LLDP and LLDP-MED can help improve security in networks.
  3. They reduce costs: The automation offered by LLDP and LLDP-MED can help reduce the cost of managing networks, as less manual intervention is required.
  4. They improve network uptime: By simplifying device configuration and reducing the need for manual intervention, LLDP and LLDP-MED can help improve network uptime.
  5. They offer better visibility into networks: The increased visibility into networks offered by LLDP and LLDP-MED can help identify issues and potential problems sooner, allowing for quicker resolution.

Deploying LLDP and LLDP-MED

LLDP is a layer 2 protocol that allows network devices to discover one another and exchange information about their configuration and capabilities. LLDP-MED is an extension of LLDP that adds support for media-specific information exchange, making it ideal for use in VoIP networks.

Deploying LLDP and LLDP-MED can be done in a number of ways, depending on the needs of your network. If you only need basic discovery and information exchange between devices, deploying LLDP alone may be sufficient. However, if you need to exchange media-specific information (such as codecs and jitter buffers), deploying LLDP-MED will be necessary.

The process of deploying LLDP and LLDP-MED is relatively straightforward. First, you’ll need to enable the protocol on each device that will be participating in the discovery process. This can usually be done via the device’s web interface or management console. Once LLDP or LLDP-MED is enabled, the devices will begin exchanging information automatically – no further configuration is required.

If you’re using LLDP-MED, you may also need to configure your devices to use the correct media type for your network. For example, if you’re using VoIP, you’ll need to configure your devices to use audio codecs that are compatible with each other. Failure to do this could result in poor call quality or dropped calls.


LLDP and LLDP-MED protocols are essential tools for any network administrator, providing an easy way to identify local connected devices, as well as allowing for configuration of the network. With their use becoming increasingly common in today’s networks, understanding how the two protocols work is a must if you want to keep your systems running smoothly. We hope this article has helped shed some light on these important protocols and given you a better idea of how they can be used in your environment.

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