ZyXEL Communications NWA3560-N User Manual page 197

one ( SNMPv1) , version t wo ( SNMPv2c) , and version t hree ( SNMPv3) . The next figure illust rat es an
SNMP m anagem ent operat ion.
Figure 97 SNMP Managem ent Model
An SNMP m anaged net work consist s of t wo m ain t ypes of com ponent : agent s and a m anager.
An agent is a m anagem ent soft ware m odule t hat resides in a m anaged device ( t he device) . An
agent t ranslat es t he local m anagem ent inform at ion from t he m anaged device int o a form
com pat ible wit h SNMP . The m anager is t he console t hrough which net work adm inist rat ors perform
net work m anagem ent funct ions. I t execut es applicat ions t hat cont rol and m onit or m anaged
devices.
The m anaged devices cont ain obj ect variables/ m anaged obj ect s t hat define each piece of
inform at ion t o be collect ed about a device. Exam ples of variables include such as num ber of
packet s received, node port st at us et c. A Managem ent I nform at ion Base ( MI B) is a collect ion of
m anaged obj ect s. SNMP allows a m anager and agent s t o com m unicat e for t he purpose of accessing
t hese obj ect s.
SNMP it self is a sim ple request / response prot ocol based on t he m anager/ agent m odel. The
m anager issues a request and t he agent ret urns responses using t he following prot ocol operat ions:
• Get - Allows t he m anager t o ret rieve an obj ect var i able from t he agent .
• Get Next - Allows t he m anager t o ret rieve t he next obj ect variable from a t able or list wit hin an
agent . I n SNMPv1, when a m anager want s t o ret rieve all elem ent s of a t able from an agent , it
init iat es a Get operat ion, followed by a series of Get Next operat ions.
• Set - Allows t he m anager t o set values for obj ect variables wit hin an agent .
• Trap - Used by t he agent t o inform t he m anager of som e event s.
NWA3000-N Series User's Guide
Chapter 15 System
197