About Snmp and the Digi One/PortServer TS 2/4 Agent

About SNMP and the Digi One/PortServer TS 2/4 Agent

This section introduces SNMP and network management in TCP/IP networks, and it describes the Digi One/PortServer TS 2/4 agent. It discusses the following:

•Network management components

•The SNMP agent

•SNMP traps

•The Digi One/PortServer TS 2/4 agent’s MIB support

•The Digi One/PortServer TS 2/4 agent’s supported traps

Network Management Components

The TCP/IP network management architecture contains the following components:

•Managed nodes such as host systems, routers, terminal and communications servers (such as Digi One/PortServer TS 2/4) and other network devices

•One or more network managers (also called network management stations), which are the points from which the network is managed

•Agents that reside on managed nodes and retrieve management information and communicate this information to network managers

•The network management protocol, SNMP, which governs the exchange of information between the nodes and stations

•Management information, which is the database of information about managed objects. This database is called the management information base (MIB).

SNMP Management Agent

Each managed node contains at least one agent—a component that responds to requests from the network manager—that retrieves network management information from its node and notifies the manager when significant events occur.

SNMP Traps

A mechanism defined by SNMP is called a trap, which is a report or “alarm” from a managed node to an SNMP manager that a significant event has occurred.

MIB Support

The agent supports the following MIBs:

•Read-write for MIB II (RFC 1213), which is an Internet-standard MIB, consisting of managed objects from the systems, interfaces, IP, ICMP, TCP, UDP, transmission, and SNMP group

•Read-write for the character-stream devices using SMIv2 MIB (RFC 1658)

•Read-write for the RS-232-like hardware devices MIB (RFC 1659)

•Read-write for the Digi One/PortServer TS 2/4 IP Network Control Protocol of the Point-to- Point Protocol MIB (RFC 1473)

Message Support

The SNMP agent supports the Set, Get, GetNext, and Trap messages as defined in RFC 1157. These messages are used as follows:

•Set, which means set the value of a specific object from one of the supported MIBs

•Get, which means retrieve the value of a specific object form one of the supported MIBs

•GetNext, which means retrieve the value of the next object in the MIB

•Trap, which means send traps to the manager when a particular type of significant event occurs

Supported Traps

The agent can send traps when any of the following occur:

•Cold starts (Digi One/PortServer TS 2/4 initializes)

•Authentication failures

14-2	About SNMP and the Digi One/PortServer TS 2/4 Agent