7

What is the difference between LLDP and LLDP-MED? Is LLDP-MED an add-on to LLDP or something completely different?

14

Media Endpoint Discovery is an enhancement of LLDP, known as LLDP-MED, that provides the following facilities:

  • Auto-discovery of LAN policies (such as VLAN, Layer 2 Priority and Differentiated services (Diffserv) settings) enabling plug and play networking.
  • Device location discovery to allow creation of location databases and, in the case of Voice over Internet Protocol (VoIP), Enhanced 911 services.
  • Extended and automated power management of Power over Ethernet (PoE) end points.
  • Inventory management, allowing network administrators to track their network devices, and determine their characteristics (manufacturer, software and hardware versions, serial or asset number).

The LLDP-MED protocol extension was formally approved and published as the standard ANSI/TIA-1057 by the Telecommunications Industry Association (TIA) in April 2006.

6

Link Layer Discovery (IEEE-802.1AB-2005) provides the base capabilities for discovery, but was seen as insufficent for IP Telephony and Real Time Video. So the LLDP-MED initiative was formed by HP, Mitel and Avaya in 2004. What does LLDP-MED provide?

  • Interoperability > provide vendor independent management capabilities, enabling different convergence endpoints to interoperate on one network.
  • Automatic deployment of convergence network policies > voice VLAN, Layer 2 and DSCP QoS policies.
  • Location Services, including Emergency Call Services > enablement of E-911, 999, 112for IP Telephony through physical location.
  • Detailed Inventory Management Capabilities > location information and accurate topology is made available. Switch acts as proxy to collect inventory, as few endpoints support SNMP.
  • Advanced PoE > Fine grain power management to support more phones per switch. Backup power conservation to extend UPS battery life during disasters.
  • IP Telephony network troubleshooting > detect incorrect voice VLAN, QoS and duplex mismatch.

Further, LLDP-MED provides a fast start behaviour which is very important for IP telephony, this means at Startup the endpoints will initially advertise at a faster rate for a limited time.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.