Monitoring Modem Devices

IPNetwork Monitor enables you to test and track the performance metrics of network modems. A built-in MIB browser lets you choose which parameters to monitor, providing access to all variables supported by the modem, along with their current values and descriptions from the MIBs.

A modem (short for modulator-demodulator) is a piece of hardware that modulates a carrier wave signal to convey information. On the receiving end, another modem demodulates this signal. The most prevalent types of modems utilize phone lines for digital information transmission. Early modems were constrained by the telephone’s voiceband audio frequencies, resulting in very slow data transfer speeds.

Today, there’s a broad range of broadband, cable, and power line modems available, achieving speeds approaching the limits of standard twisted pair cables and other media like fiber optics, radio, and cellular phone networks.

Modems are primarily used to provide internet access; connection speed can fluctuate significantly depending on the transmission medium. Because different media might be available simultaneously, various modem types can offer redundant internet connectivity should the primary connection fail.

Mobile broadband modems enable reliable internet access on the go, assuming adequate cellular coverage in the area.

Many modems are hybrid network devices, incorporating the functionality of network switches and/or routers. For instance, ADSL modems connected to a high-quality (low-noise) phone line can function as bridges, connecting geographically separated locations into a unified network.

Based on the modem type, additional features may be included (such as firewall, router, WiFi access point, DHCP, and other services), transforming it into an all-in-one solution suitable for small networks. Power line modems can be utilized to manage in-home devices (e.g., providing access to “smart home” or IoT functionality).

Common Modem Monitoring Scenarios

Besides collecting general health status data, monitoring modems allows you to:

  • Verify connection quality and switch to a backup if the current connection deteriorates.
  • Conduct traffic analysis (categorize traffic by user and protocol).
  • Identify potentially malicious traffic or other security-related activity.

MIBs for Modem Device Monitoring

The following MIBs are commonly used for monitoring modem devices:

  • ADSL-DMT-LINE-MIB

    Managed object descriptions for ADSL DMT line interfaces.
  • CISCO-ADSL-CAP-LINE-MIB

    This MIB module is a vendor-specific extension of ADSL-LINE-MIB, mirroring its structure.
  • CISCO-ADSL-DMT-LINE-MIB

    This MIB module is a Cisco-specific extension of ADSL-LINE-MIB, mirroring its structure.
  • CISCO-CALL-TRACKER-MODEM-MIB

    This MIB provides modem call data for monitoring call progress and status. It expands upon tables in ciscoCallTrackerMIB (CISCO-CALL-TRACKER-MIB).
  • CISCO-IDSL-LINE-MIB

    This MIB describes IDSL (ISDN Digital Line Subscriber) line interfaces. Its structure is similar to ADSL-LINE-MIB (RFC-2662). Note that its tables do not necessarily extend those defined in ADSL-LINE-MIB.
  • CISCO-IETF-VDSL-LINE-MIB

    This MIB defines objects for managing VDSL modem pairs. Each VDSL line has an ifTable entry.
  • CISCO-MODEM-MGMT-MIB

    This MIB contains modem management information.
  • CISCO-SDSL-LINE-MIB

    This MIB describes symmetric DSL line interfaces. Its structure is similar to and consistent with ADSL-LINE-MIB, ADSL-DMT-LINE-MIB, CISCO-ADSL-DMT-LINE-MIB, and CISCO-ADSL-CAP-LINE-MIB.
  • CISCO-XDSL-LINE-MIB

    The tables in this MIB contain general managed objects applicable to various modem types. Its structure resembles ADSL-LINE-MIB, CISCO-SDSL-LINE-MIB, ADSL-DMT-LINE-MIB, and CISCO-ADSL-CAP-LINE-MIB.
  • DOCS-BPI2-MIB

    MIB for DOCSIS Baseline Privacy Plus Interface (BPI+) on cable modems and CMTSs.
  • DOCS-BPI-MIB

    MIB for the DOCSIS Baseline Privacy Interface (BPI) on cable modems and CMTSs. Its implementation is required for DOCSIS 1.0 cable modems using BPI.
  • DOCS-CABLE-DEVICE-MIB

    MIB for MCNS-compliant cable modems and CMTSs.
  • DOCS-CABLE-DEVICE-TRAP-MIB

    This MIB extends RFC2669 (CABLE DEVICE MIB). It defines trap objects for cable modems and CMTSs.
  • DOCS-IF-EXT-MIB
    Extension module for rfc2670 DOCS-IF-MIB.
  • DOCS-IF-MIB

    MIB for DOCSIS 2.0 RF interfaces in cable modems and CMTSs.
  • MODEM-MIB
    MIB for dial-up modem management.

Start monitoring your modems with a free 30-day trial of IPNetwork Monitor. IPNetwork Monitor enables network performance monitoring, network usage auditing, fault detection, and identification of unauthorized access. It can communicate with any SNMP-enabled device.

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IPNetwork Monitor 1.0 build 141 of March 11, 2024. File size: 112MB