CHARACTER-MIB

MIB Reference — IPNetwork Monitor · Updated September 14, 2026

All MIBsCHARACTER-MIB

Organization: IETF Character MIB Working Group

Last Updated: 1994-05-26

Category: Hardware and Environment, Network Interfaces

Description: Defines managed objects for character stream devices and their sessions, covering terminal servers and similar character-oriented port hardware.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring CHARACTER-MIB with a free 30-day trial of IPNetwork Monitor.

What Is CHARACTER-MIB?

CHARACTER-MIB is a vendor-neutral IETF standards-based MIB (RFC 1316) defining managed objects for character-oriented stream devices and their sessions, historically covering terminal servers, async port concentrators, and similar RS-232/character-stream port hardware. It exposes objects describing device/port identity and configuration along with per-session information for character-stream connections. Its monitoring focus is on connectivity and session/software status for character-oriented ports rather than classic environmental sensors: tracking active sessions per port and port configuration to confirm terminal-server ports are functioning and sessions are not hanging or failing to establish. As a foundational IETF MIB it is commonly used alongside the RS-232-like MIB and standard interface MIBs (IF-MIB) for full port/session visibility on character-stream devices. It is deployed on terminal servers, console servers, and async port-concentrator devices found in legacy data-center and lab console-access environments. Engineers implementing or auditing this functionality typically reference the CHARACTER-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in CHARACTER-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

  • vendor-neutral, standards-based MIB (RFC 1316), not tied to a specific manufacturer
  • terminal servers / async port concentrators / character-stream console devices

Monitoring Examples

No sample objects were provided in the metadata for this module; based on RFC 1316's known structure, an admin would typically poll a character device table and an associated session table (indexed by device/port) to check session state and duration per character port, but specific object names cannot be confirmed from the given sample_objects.

What Can Be Monitored

  • character port configuration
  • active session count per port
  • session state/duration (inferred from RFC 1316 structure, not confirmed via sample_objects)
Imported Objects

From IF-MIB

InterfaceIndex

From RFC1213-MIB

mib-2
transmission

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Gauge32
Integer32
MODULE-IDENTITY
NOTIFICATION-TYPE
OBJECT-TYPE
TimeTicks

From SNMPv2-TC

AutonomousType
DisplayString
InstancePointer
TEXTUAL-CONVENTION

How to Use in IPNetwork Monitor

Example using charPortInCharacters OID:

Select a Terminal servers / async port concentrator (character-stream devices) as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type charPortInCharacters into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. It reports the total number of characters detected as input from the port since system re-initialization and while the port operational state was 'up', 'active', or 'maintenance', including, for example, framing, flow control (i.e. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.
OIDs

RFC description

Standard IETF MIB module for character stream device and serial port management.

Start monitoring Terminal servers / async port concentrators (character-stream devices) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download CHARACTER-MIB