ZyXEL Communications P-334WT Support Notes page 141

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:
1. Reads
Read is used to monitor the managed devices, NMSs read variables that are maintained by the
devices.
2. Writes
Write is used to control the managed devices, NMSs write variables that are stored in the
managed devices.
3. 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.
4. Traps
The managed devices to asynchronously report certain events to NMSs use trap.