GS2210 Series User’s Guide
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Link Layer Discovery Protocol (LLDP)
33.1 LLDP Overview
The LLDP ( Link Layer Discover y Pr ot ocol) is a layer 2 pr ot ocol. I t allow s a net w or k device t o
adver t ise it s ident it y and capabilit ies on t he local net wor k. I t also allow s t he device t o m aint ain and
st or e infor m at ion fr om adj acent devices w hich ar e dir ect ly connect ed t o t he net w or k device. This
helps an adm inist rat or discover net w or k changes and per for m necessar y net wor k r econfigurat ion
and m anagem ent . The device infor m at ion is encapsulat ed in t he LLDPDUs ( LLDP dat a unit s) in t he
form of TLV ( Type, Lengt h, Value) . Device inform at ion car r ied in t he r eceived LLDPDUs is st or ed in
t he st andard MI B.
The Swit ch support s t hese basic m anagem ent TLVs.
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End of LLDPDU ( m andat or y )
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Chassis I D ( m andat or y)
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Por t I D ( m andat or y)
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Tim e t o Live ( m andat or y)
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Por t Descr ipt ion ( opt ional)
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Sy st em Nam e ( opt ional)
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Syst em Descr ipt ion ( opt ional)
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Syst em Capabilit ies ( opt ional)
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Managem ent Addr ess ( opt ional)
The Swit ch also suppor t s t he I EEE 802.1 and I EEE 802.3 or ganizat ionally- specific TLVs.
I EEE 802.1 specific TLVs:
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Por t VLAN I D TLV ( opt ional)
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Por t and Pr ot ocol VLAN I D TLV ( opt ional)
I EEE 802.3 specific TLVs:
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MAC/ PHY Configurat ion/ St at us TLV ( opt ional)
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Pow er via MDI TLV ( opt ional, For PoE m odels only)
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Link Aggr egat ion TLV ( opt ional)
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Maxim um Fram e Size TLV ( opt ional)
The opt ional TLVs ar e inser t ed bet w een t he Tim e To Live TLV and t he End of LLDPDU TLV.
The next figur e dem onst rat es t hat t he net w or k devices Swit ches and Rout er s ( S and R) t ransm it
and r eceive device infor m at ion via LLDPDU and t he net w or k m anager can quer y t he infor m at ion
using Sim ple Net w or k Managem ent Pr ot ocol ( SNMP) .
