Filter
Top Products
Prestige 2802HW(L)-Ix Support Notes
All contents copyright (c) 2007 ZyXEL Communications Corporation.
42
For example, the encoding of a text string includes an indication that the data unit is a string, along with its
length and value. ASN.1 is a flexible way of defining protocols, especially for network management protocols
where nodes may support different sets of manageable variables.
The net of variables that each node supports is called the
Management Information Base
(MIB). The MIB is
made up of several parts, including the Standard MIB, specified as part of SNMP, and Enterprise Specific MIB,
which are defined by different manufacturer for hardware specific management.
The current Internet-standard MIB, MIB-II, is defined in RFC 1213 and contains 171 objects. These objects are
grouped by protocol (including TCP, IP, UDP, SNMP, and other categories, including 'system' and 'interface.'
The Internet Management Model is as shown in figure 1. Interactions between the NMS and managed devices
can be any of four different types of commands:
6. Reads
Read is used to monitor the managed devices, NMSs read variables that are maintained by the devices.
7. Writes
Write is used to control the managed devices, NMSs write variables that are stored in the managed
devices.
8. Traversal operations
NMSs use these operations to determine which variables a managed device supports and to sequentially
gather information from variable tables (such as IP routing table) in managed devices.
9. Traps
The managed devices to asynchronously report certain events to NMSs use trap.