ZyXEL Communications XS1920 Series, User Manual

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Chapter 40 Access Control
XS1920 Series User’s Guide
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An agent is a management software module that resides in a managed Switch (the Switch). An
agent translates the local management information from the managed Switch into a form
compatible with SNMP. The manager is the console through which network administrators perform
network management functions. It executes applications that control and monitor managed
devices.
The managed devices contain object variables/managed objects that define each piece of
information to be collected about a Switch. Examples of variables include number of packets
received, node port status and so on. A Management Information Base (MIB) is a collection of
managed objects. SNMP allows a manager and agents to communicate for the purpose of accessing
these objects.
SNMP itself is a simple request/response protocol based on the manager/agent model. The
manager issues a request and the agent returns responses using the following protocol operations:
SNMP v3 and Security
SNMP v3 enhances security for SNMP management. SNMP managers can be required to
authenticate with agents before conducting SNMP management sessions.
Security can be further enhanced by encrypting the SNMP messages sent from the managers.
Encryption protects the contents of the SNMP messages. When the contents of the SNMP messages
are encrypted, only the intended recipients can read them.
Supported MIBs
MIBs let administrators collect statistics and monitor status and performance.
The Switch supports the following MIBs:
• SNMP MIB II (RFC 1213)
• RFC 1157 SNMP v1
• RFC 1493 Bridge MIBs
• RFC 1643 Ethernet MIBs
• RFC 1155 SMI
• RFC 2674 SNMPv2, SNMPv2c
• RFC 1757 RMON
• SNMPv2, SNMPv2c or later version, compliant with RFC 2011 SNMPv2 MIB for IP, RFC 2012
SNMPv2 MIB for TCP, RFC 2013 SNMPv2 MIB for UDP
Table 185
SNMP Commands
LABEL DESCRIPTION
Get Allows the manager to retrieve an object variable from the agent.
GetNext Allows the manager to retrieve the next object variable from a table or list within an agent.
In SNMPv1, when a manager wants to retrieve all elements of a table from an agent, it
initiates a Get operation, followed by a series of GetNext operations.
Set Allows the manager to set values for object variables within an agent.
Trap Used by the agent to inform the manager of some events.