Appendix E: Lldp-Med - HP ProCurve 3500-24 Reference Manual

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Appendix E: LLDP-MED

IEEE 802 . 1 AB Link Layer Discovery Protocol (LLDP) provides a standards-based method that enables devices
such as HP ProCurve switches to advertise themselves to adjacent devices and to learn about adjacent LLDP
devices . An LLDP packet transmitted by an HP ProCurve switch contains data about the switch and port .
The switch advertises itself to adjacent (neighbor) devices by transmitting LLDP data packets out all ports on
which outbound LLDP is enabled, and reading LLDP advertisements from neighbor devices on ports that are
inbound LLDP-enabled . An LLDP-enabled port receiving LLDP packets inbound from neighbor devices stores
the packet data in a neighbor database (MIB) .
LLDP provides the base capabilities for network devices, but was not considered sufficient for IP telephony
devices . As a result, in 2004, an initiative by Mitel, HP ProCurve, Avaya, and Enterasys was undertaken to
enhance LLDP so that it could better support IP telephony devices . The development of LLDP-Medium Endpoint
Discovery (LLDP-MED) (ANSI/TIA-1057/D6) extended the LLDP standard to support advanced features on
the network edge for VoIP endpoint devices with specialized capabilities and LLDP-MED standards-based
functionality . The extensions to LLDP include the specification of additional TLV (type, length, and value)
entries specifically for VoIP management .
LLDP-MED benefits include:
• Plug-and-play provisioning for MED-capable, VoIP endpoint devices
• Simplified, vendor-independent management, enabling different IP telephony systems to interoperate on one
network
• Automatic deployment of convergence network policies that include voice VLANs, Layer 2/CoS priority,
and Layer 3/QoS priority
• Configurable endpoint location data to support the Emergency Call Service (ECS) such as Enhanced 911,
999, and 112
• Detailed VoIP endpoint data inventory readable via SNMP from the switch
• Power over Ethernet (PoE) status and troubleshooting support via SNMP
• Support for IP telephony network troubleshooting of call quality issues via SNMP
Figure A5.