Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring SNMP (Rev. 03)
Simple Network Management Protocol
© 2008 Foundry Networks, Inc.
Page 4 of 48
Structure of Management Information (SMI)
Management information is a collection of managed objects, residing in a virtual information store,
termed the Management Information Base (MIB). Collections of related objects are defined in MIB
modules. Each type of object has a name, a syntax, and an encoding. The name is represented
uniquely as an OBJECT IDENTIFIER. An OBJECT IDENTIFIER is an administratively assigned
name for identifying one object, regardless of the semantics associated with the object. The
encoding of an object type is the way the instances of that object type are represented using the
object type syntax. Names are used to identify managed objects.
SNMP Manager
An SNMP Manager is a software module in a management system responsible for managing part
or the entire configuration on behalf of network management applications and users.
Management Information Base (MIB)
A Management Information Base (MIB) consists of a collection of objects organized into groups.
Objects hold values that represent managed resources. All managed objects in the SNMP
environment are arranged in a hierarchical or tree structure. A MIB is the repository for
information about device parameters and network data.
SNMP Engine-ID
The SNMP Engine ID is a 5 to 32 byte long administratively unique identifier of a participant in
SNMP communication within a single management domain. The SNMP Manager and SNMP
Agent must be configured by an administrator to have unique SNMP Engine IDs.
SNMP View Records
With the community-based authentication defined in SNMPv1, an authorized user is granted
access to the whole MIB tree for reading or for reading/writing. With SNMPv1, it is not possible to
allow diverse authorized users access to different portions of the MIB database.
This deficiency is overcome in SNMPv3 with the introduction of
views
. A view is a set of rules
that define which portion of the MIB database should be “visible” to a specific user. The rules are
defined by the Object Identifier (OID) of a node in the MIB tree, and the type of rule:
included
or
excluded
. The OID defines a
view family –
a set of object identifiers that have a common prefix. A
single rule (included or excluded) in the view is applied to view family, not only to a single OID.
SNMP Notifications
The SNMP notification messages allow devices to send asynchronous messages to the SNMP
Managers. Devices can send notifications to SNMP Managers when particular events occur. For
example, an agent might send a message to a Manager when the agent experiences an error
condition.
NOTE
All traps except the ones that are sent with SNMPv1 have a request ID as part of
the PDU.
SNMP notifications can be sent as traps or Inform requests. Traps are unreliable because the
receiver does not send any acknowledgment when it receives a trap. However, an SNMP Manager