General Lldp Operation; Packet Boundaries In A Network Topology - ProCurve 6400cl Management And Configuration Manual

PSAP (Public Safety Answering Point): PSAPs are typically emergency
telephone facilities established as a first point to receive emergency (911) calls
and to dispatch emergency response services such as police, fire and
emergency medical services.
PSE (Power-Sourcing Equipment): A PSE, such as a PoE module installed
in a Series 5300xl switch, provides power to IEEE 802.3af-compliant PDs
directly connected to the ports on the module.
TLV (Type-Length-Value): A data unit that includes a data type field, a data
unit length field (in bytes), and a field containing the actual data the unit is
designed to carry (as an alphanumeric string, a bitmap, or a subgroup of
information). Some TLVs include subelements that occur as separate data
points in displays of information maintained by the switch for LLDP
advertisements. (That is, some TLVs include multiple data points or
subelements.)

General LLDP Operation

An LLDP packet contains data about the transmitting 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. (LLDP is a one-way protocol and does not include any
acknowledgement mechanism.) An LLDP-enabled port receiving LLDP
packets inbound from neighbor devices stores the packet data in a Neighbor
database (MIB).
LLDP-MED
This capability is an extension to LLDP and is available on 5300xl switches
running software release E.10.02 or greater, and on 4200vl switches. Refer to
"LLDP-MED (Media-Endpoint-Discovery) for the 5300xl and 4200vl Switches"
on page 15-44.

Packet Boundaries in a Network Topology

Where multiple LLDP devices are directly connected, an outbound LLDP
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packet travels only to the next LLDP device. An LLDP-capable device does
not forward LLDP packets to any other devices, regardless of whether
they are LLDP-enabled.
Configuring for Network Management Applications
LLDP (Link-Layer Discovery Protocol)
15-27