Enterasys G3G170-24, Cli Reference Manual

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Configuring Link Layer Discovery Protocol and LLDP-MED
Enterasys G-Series CLI Reference 3-13
Configuring Link Layer Discovery Protocol and LLDP-MED
Overview
The Link Layer Discovery Protocol (LLPD) is similar to the Enterasys Discovery Protocol and the
Cisco Discovery Protocol in that it provides an industry standard, vendor ‐ neutral way to allow
network devices to advertise their identities and capabilities on a local area network, and to
discover that information about their neighbors.
LLDP ‐ MED is an enhancement to LLDP that provides the following benefits:
• Extended and automated power management of Power over Ethernet endpoints
• Inventory management, allowing network administrators to track their network devices and
to determine their characteristics, such as manufacturer, software and hardware versions, and
serial or asset numbers
The information sent by an LLDP ‐ enabled device is extracted and tabulated by its peers. The
communication can be done when information changes or on a periodic basis. The information
tabulated is aged to ensure that it is kept up to date. Ports can be configured to send this
information, receive this information, or both send and receive.
Either LLDP or LLDP ‐ MED, but not both, can be used on an interface between two devices. A
switch port uses LLDP ‐ MED when it detects that an LLDP ‐ MED ‐ capable device is connected to it.
LLDP information is contained within a Link Layer Discovery Protocol Data Unit (LLDPDU) sent
in a single 802.3 Ethernet frame. The information fields in LLDPDU are a sequence of short,
variable ‐ length, information elements known as TLVs — type, length, and value fields where:
• Type identifies what kind of information is being sent
• Length indicates the length of the information string in octets
• Value is the actual information that needs to be sent
The LLDP standard specifies that certain TLVs are mandatory in transmitted LLDPDUs, while
others are optional. You can configure on a port ‐ specific basis which optional LLDP and LLDP ‐
MED TLVs should be sent in LLDPDUs.
Purpose
To review and configure LLPD and LLPD ‐ MED.
Commands
The commands used to review and configure the CDP discovery protocol are listed below.
For information about... Refer to page...
show lldp 3-14
show lldp port status 3-15
show lldp port trap 3-16
show lldp port tx-tlv 3-16
show lldp port location-info 3-17
show lldp port local-info 3-17