Chapter 43 Access Control
GS2210 Series User’s Guide
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43.7.1 About SNMP
Sim ple Net wor k Managem ent Pr ot ocol ( SNMP) is an applicat ion layer pr ot ocol used t o m anage and
m onit or TCP/ I P- based devices. SNMP is used t o exchange m anagem ent inform at ion bet w een t he
net wor k m anagem ent syst em ( NMS) and a net w ork elem ent ( NE) . A m anager st at ion can m anage
and m onit or t he Swit ch t hr ough t he net w or k via SNMP ver sion 1 ( SNMPv1) , SNMP ver sion 2c or
SNMP ver sion 3. The next figur e illust rat es an SNMP m anagem ent operat ion. SNMP is only available
if TCP/ I P is configur ed.
Figure 263
SNMP Managem ent Model
An SNMP m anaged net w or k consist s of t w o m ain com ponent s: agent s and a m anager.
An agent is a m anagem ent soft war e m odule t hat r esides in a m anaged Sw it ch ( t he Sw it ch) . An
agent t ranslat es t he local m anagem ent infor m at ion fr om t he m anaged Swit ch int o a for m
com pat ible w it h SNMP. The m anager is t he console t hr ough which net w or k adm inist rat or s perfor m
net wor k m anagem ent funct ions. I t execut es applicat ions t hat cont r ol and m onit or m anaged
devices.
The m anaged devices cont ain obj ect var iables/ m anaged obj ect s t hat define each piece of
infor m at ion t o be collect ed about a Swit ch. Ex am ples of var iables include num ber of packet s
r eceived, node por t st at us and so on. A Managem ent I nfor m at ion Base ( MI B) is a collect ion of
m anaged obj ect s. SNMP allow s a m anager and agent s t o com m unicat e for t he pur pose of accessing
t hese obj ect s.
SNMP it self is a sim ple r equest / r esponse pr ot ocol based on t he m anager / agent m odel. The
m anager issues a r equest and t he agent r et ur ns r esponses using t he follow ing pr ot ocol operat ions:
SNMP v3 and Security
SNMP v3 enhances secur it y for SNMP m anagem ent . SNMP m anagers can be required t o
aut hent icat e w it h agent s befor e conduct ing SNMP m anagem ent sessions.
Table 188
SNMP Com m ands
LABEL
DESCRIPTION
Get
Allow s t he m anager t o r et r ieve an obj ect var iable fr om t he agent .
Get Nex t
Allow s t he m anager t o r et r ieve t he nex t obj ect var iable from a t able or list w it hin an agent .
I n SNMPv 1, w hen a m anager want s t o r et r ieve all elem ent s of a t able from an agent , it
init iat es a Get operat ion, follow ed by a ser ies of Get Next operat ions.
Set
Allow s t he m anager t o set values for obj ect var iables w it hin an agent .
Trap
Used by t he agent t o inform t he m anager of som e event s.
