BRCM-CM-MGMT-EXT-MIB

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Organization: Broadcom Corporation

Last Updated: 2005-04-18

Category: Cable/DOCSIS

Description: Extends cable modem management with Broadcom-specific DOCSIS configuration and diagnostics.

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What Is BRCM-CM-MGMT-EXT-MIB?

BRCM-CM-MGMT-EXT-MIB is a Broadcom vendor extension MIB for DOCSIS cable modems that use a Broadcom chipset, adding management objects not covered by the standard DOCSIS cable modem MIBs. It exposes downstream channel scanning configuration and results, a scan frequency list and per-entry scan table, along with base status objects such as a standby switch status flag. Its monitoring purpose is largely diagnostic/software status of the modem's RF front end: confirming which frequencies the modem has scanned or is configured to scan, and detecting standby/redundancy switch state on modems that support it, both useful for troubleshooting slow or failed registration to the DOCSIS network. It explicitly depends on and augments the standard DOCSIS cable modem MIB set (e.g., DOCS-CABLE-DEVICE-MIB) rather than standing alone. Deployment context is residential or SMB DOCSIS cable modems/gateways built on Broadcom silicon, managed by an MSO's provisioning and monitoring systems. Engineers can download the BRCM-CM-MGMT-EXT-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in BRCM-CM-MGMT-EXT-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

Broadcom-chipset DOCSIS cable modem / residential gateway

Monitoring Examples

An operator would poll cmScanTable/cmScanEntry by cmScanIndex to read cmScanFrequency values and compare them against the expected downstream plan, revealing if the modem is scanning the wrong frequency range. Checking cmMgmtExtBaseStandbySwitchStatus helps confirm whether a modem with redundant tuners has failed over. A modem stuck cycling through cmScanPushFrequency without locking onto a downstream channel points to an RF signal or plant issue at that location.

What Can Be Monitored

downstream scan frequency list
per-frequency scan results
standby/redundant tuner switch status
modem RF scanning configuration

Imported Objects

From BRCM-CABLEDATA-MGMT-MIB

broadcomCableDataMgmt

OBJECT-IDENTITY

From SNMPv2-SMI

MODULE-IDENTITY
OBJECT-TYPE

OIDs

OID symbolic	OID numeric	Type	Access	Description
cmMgmtExt	1.3.6.1.4.1.4413.50.1.1.99.4413.2			Broadcom CM management extension MIB. This MIB is supported only for products implementing the Broadcom CM vendor extension.
cmMgmtExtBase	1.3.6.1.4.1.4413.50.1.1.99.4413.2.1
INT cmMgmtExtBaseStandbySwitchStatus	1.3.6.1.4.1.4413.50.1.1.99.4413.2.1.1	INTEGER	read-write	Reports/Sets the position of the standby switch. A GET on this object returns the current state of the standby switch. A SET to a value of 'on(1)' enables standby mode for the device. A SET to a value of 'off(2)' disables standby mode for the device. When standby-mode is enabled 'on(1)', the device blocks WAN data traffic to/from the CPEs.
cmMgmtExtScan	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2
I32 cmScanPushFrequency	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2.1	Integer32	read-write	Setting this object will add a new entry to the cmScanTable. The new entry will be at index 1, and all existing entries will be re-indexed starting at 2. If the table is full, the last entry in the table will be dropped. If the value set here already exists in the table, it will be moved from its current position in the table to become entry 1 (a duplicate entry will not be added). Setting this object to a value of 0 will flush the cmScanTable. When read, this object always returns 0.
cmScanTable	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2.2		not-accessible	A table of the most recent known good frequencies to which the CM has registered. The most recent good frequency will be at index 1, with subsequent entries being in chronological order from newest to oldest. Note that the table will not grow unbounded. Once the maximum number of entries is reached, the oldest entries will be discarded.
cmScanEntry	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2.2.1		not-accessible	An entry which identifies a downstream frequency to which the CM has recently successfully registered.
I32 cmScanIndex	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2.2.1.1	Integer32	not-accessible	Identifies the instance of this scan entry.
I32 cmScanFrequency	1.3.6.1.4.1.4413.50.1.1.99.4413.2.2.2.1.2	Integer32	read-only	A downstream frequency to which the CM has recently successfully registered, or which has been provisioned by way of a set to cmScanPushFrequency.

RFC description

Broadcom cable modem management extension for runtime CM operations and monitoring.

Start monitoring Broadcom-based cable modems/gateways 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 BRCM-CM-MGMT-EXT-MIB

What Is BRCM-CM-MGMT-EXT-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

RFC description