DOCS-IFEXT2-MIB

All MIBs › DOCS-IFEXT2-MIB

Organization: Cable Television Laboratories, Inc

Last Updated: 2010-10-08

Category: Domain: CATV/Cable, Standard: DOCSIS

Description: Provides second-generation extensions to DOCSIS cable interface management for enhanced CMTS features.

Start monitoring vendor-neutral, standards-based MIB, any SNMPv3-capable network device (SNMP engine identity/boot/clock status) 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.

What Is DOCS-IFEXT2-MIB?

DOCS-IFEXT2-MIB is a CableLabs/IETF vendor-neutral standards MIB, part of the DOCSIS MIB family, that provides second-generation extensions to DOCSIS cable-interface management, specifically adding DOCSIS 2.0 SCDMA (Synchronous Code Division Multiple Access) capabilities such as Maximum Scheduled Codes (MSC) limiting for cable modems. It exposes per-cable-modem status objects covering MSC state, code ratio, power headroom/shortfall, and effective transmit power, along with a CMTS-side global enable and a per-modem status mirror table. Its monitoring focus is on cable-modem RF performance and DOCSIS upstream channel health — operators use power headroom and power shortfall to detect modems running low on available transmit power, a common sign of a marginal cable plant, and use the code ratio/state objects to see how SCDMA code allocation is constraining a modem's throughput. It directly depends on, and extends, the base DOCS-IF-MIB (DOCSIS Interface MIB) and the broader DOCSIS 2.0 specification from CableLabs. It is deployed on cable modems (CMs) and Cable Modem Termination Systems (CMTSs) in HFC (hybrid fiber-coax) cable broadband access networks. Engineers implementing or auditing this functionality typically reference the DOCS-IFEXT2-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in DOCS-IFEXT2-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 DOCSIS MIB — cable modems (CM) and Cable Modem Termination Systems (CMTS)

Monitoring Examples

A cable operator would poll docsIfExt2CmMscStatusTable/docsIfExt2CmMscStatusEntry on a subscriber cable modem to check docsIfExt2CmMscStatusPowerHeadroom and docsIfExt2CmMscStatusPowerShortfall, identifying modems close to their maximum transmit power, indicating a noisy or long cable run needing plant maintenance. On the CMTS side, docsIfExt2CmtsMscGlobalEnable confirms whether MSC limiting is active system-wide, while docsIfExt2CmtsCmMscStatusTable lets the CMTS aggregate per-modem MSC status across all modems on a channel to spot a cluster of modems with degraded docsIfExt2CmMscStatusCodeRatio, suggesting a shared upstream noise problem.

What Can Be Monitored

cable modem MSC (Maximum Scheduled Codes) status
transmit power headroom/shortfall
SCDMA code allocation ratio
CMTS-wide MSC enable state

Imported Objects

From CLAB-DEF-MIB

clabProjDocsis

OBJECT-IDENTITY

From DOCS-IF-MIB

TenthdB
TenthdBmV
docsIfCmtsCmStatusIndex	OBJECT-TYPE

From IF-MIB

ifIndex

OBJECT-TYPE

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Gauge32
MODULE-IDENTITY
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

TruthValue

How to Use in IPNetwork Monitor

Example using docsIfExt2CmtsUpChannelMSCTotalCMs OID:

Select a DOCSIS cable modem/CMT (SCDMA/MSC extension, vendor-neutral CableLabs standard) 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 docsIfExt2CmtsUpChannelMSCTotalCMs 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 CMs with docsIfCmtsCmStatusValue of registrationComplete with MSC active. 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 Gauge32-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

OID symbolic	OID numeric	Type	Access	Description
docsIfExt2Mib	1.3.6.1.4.1.4491.2.1.5			This MIB module contains the management objects that enhance DOCSIS 2.0 feature set. It includes SCDMA capability of limiting the number of codes assigned to a CM over the total active codes, referred as Maximum Scheduled Codes (MSC).
docsIfExt2Notifications	1.3.6.1.4.1.4491.2.1.5.0
docsIfExt2MibObjects	1.3.6.1.4.1.4491.2.1.5.1
docsIfExt2BaseObjects	1.3.6.1.4.1.4491.2.1.5.1.1
docsIfExt2CmObjects	1.3.6.1.4.1.4491.2.1.5.1.2
docsIfExt2CmMscStatusTable	1.3.6.1.4.1.4491.2.1.5.1.2.1		not-accessible	This table extends the docsIfUpstreamChannelTable to report the CM MSC status.
docsIfExt2CmMscStatusEntry	1.3.6.1.4.1.4491.2.1.5.1.2.1.1		not-accessible	As an extension of docsIfUpstreamChannelTable this table has entries for each ifEntry with an ifType of docsCableUpstream(129) This entry is instantiated by the CM only if the CM is currently in SCDMA mode.
INT docsIfExt2CmMscStatusState	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.1	INTEGER	read-only	Indicates the current state of the Maximum Scheduled Codes feature on the CM. channelEnabled(1) S-CDMA Maximum Scheduled Codes is enabled in the UCD TLV-17. channelDisabled(2) S-CDMA Maximum Scheduled Codes is disabled in the UCD TLV-17 or a UCD has been received that does not contain that TLV. Active(3) The CM has received a Ranging Response that contains a non-zero TLV-10 and therefore has MSC activated. This state overrides the channelEnabled(1) state. Inactive(4) The CM has received a Ranging Response that does not contain TLV-10 or has it set to 0. This state overrides the channelEnabled(1) state. Unknown(5) CM has not yet received a UCD to determine if MSC is enabled or disabled on that channel.
TEN docsIfExt2CmMscStatusPowerShortfall	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.2	TenthdB	read-only	Indicates the Power Shortfall at the CM, in units of tenth dB. The value is provided by the CM and is sent in the RNG-REQ message. It is internally calculated in units of quarter dB and is rounded upward for this MIB object to the nearest tenth dB. A value of zero indicates that the CM has no power shortfall.
U32 docsIfExt2CmMscStatusCodeRatio	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.3	Unsigned32	read-only	Indicates the maximum ratio of number of active codes to Maximum Scheduled Codes that the CM can support, as reported in the Ranging Request.
U32 docsIfExt2CmMscStatusMaximumScheduledCodes	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.4	Unsigned32	read-only	Indicates the Maximum Scheduled Codes in use by the CM. The value is provided by the CMTS through a TLV value in the RNG-RSP message. Note that not all values from 4..128 are valid. A value of zero when docsIfExt2CmMscStatusSate is active(3) indicates there is no maximum scheduled codes value. This object should remain at zero when docsIfExt2CmMscStatusState is not active(3).
TEN docsIfExt2CmMscStatusPowerHeadroom	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.5	TenthdB	read-only	Indicates the Maximum Scheduled Codes Power Headroom in use by the CM, in units of tenth dB. The value is provided by the CMTS in units of quarter dB through TLV-11 in the RNG-RSP message and is rounded upward for this MIB object to the nearest tenth dB. A value of zero indicates the CMTS provided no Power Headroom. This object should remain at zero when docsIfExt2CmMscStatusState is not active(3).
TEN docsIfExt2CmMscStatusEffectivePower	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.6	TenthdBmV	read-only	Indicates the Effective Transmit Power of the CM. This is the power that would result hypothetically if, in a spreader-on frame, the CM were to transmit on all active codes with 64QAM modulation. This object should be equal to docsIfCmStatusTxPower when docsIfExt2CmMscStatusState is not active(3).
INT docsIfExt2CmMscStatusIUC2Control	1.3.6.1.4.1.4491.2.1.5.1.2.1.1.7	INTEGER	read-write	The CM usage of IUC2 when MSC is enabled: noIUC2(1): CM usage of IUC2 is prohibited limitedIUC2(2): CM is allowed to use IUC2 as long as the CM does not exceed MSC freeIUC2(3): CM is allowed to use IUC2 without regard for MSC. With limitedIUC2(2), there may be cases where a CM cannot ensure that the use of IUC2 would not exceed MSC. In these cases, the CM MUST NOT use IUC2.
T/F docsIfExt2CmClearLearnedMacAddresses	1.3.6.1.4.1.4491.2.1.5.1.2.2	TruthValue	read-write	If set to 'true', the CM clears all entries in the CM forwarding database for all learned MAC addresses that are not eSAFE or provisioned MAC addresses. Reading this object always returns 'false'.
docsIfExt2CmtsObjects	1.3.6.1.4.1.4491.2.1.5.1.3
T/F docsIfExt2CmtsMscGlobalEnable	1.3.6.1.4.1.4491.2.1.5.1.3.1	TruthValue	read-write	Indicates the global state of the Maximum Scheduled Code feature on the CMTS. The value true(1) indicates that this feature can be enabled on individual logical channels on the CMTS. The value false(2) indicates that the feature is not in operations on the CMTS. Note that the MIB object docsIfExt2CmtsUpChannelMscState exists to enable or disable Maximum Scheduled Codes on a per logical channel basis.
docsIfExt2CmtsCmMscStatusTable	1.3.6.1.4.1.4491.2.1.5.1.3.2		not-accessible	This table extends the docsIfCmtsCmStatusTable to report CM MSC status.
docsIfExt2CmtsCmMscStatusEntry	1.3.6.1.4.1.4491.2.1.5.1.3.2.1		not-accessible	An entry for MSC CM status report. Only CMs allocated to SCDMA upstream channels are included in this table.
TEN docsIfExt2CmtsCmMscStatusPowerShortfall	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.1	TenthdB	read-only	Indicates the Power Shortfall at the CM, in units of tenth dB. The value is provided by the CM and is sent in the RNG-REQ message. It is internally calculated in units of quarter dB and is rounded upward for this MIB object to the nearest tenth dB. A value of zero indicates that the CM has no power shortfall.
U32 docsIfExt2CmtsCmMscStatusCodeRatio	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.2	Unsigned32	read-only	Indicates the maximum ratio of number of active codes to Maximum Scheduled Codes that the CM reported in the Ranging Request.
U32 docsIfExt2CmtsCmMscStatusMaximumScheduledCodes	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.3	Unsigned32	read-only	Indicates the Maximum Scheduled Codes value in use by the CM. The value is provided by the CMTS through a TLV in the RNG-RSP message. Note that not all values from 4..128 are valid. A value of zero indicates there is no Maximum Scheduled Codes, or that the CM does not support the Maximum Scheduled Codes feature.
TEN docsIfExt2CmtsCmMscStatusPowerHeadroom	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.4	TenthdB	read-only	Indicates the Maximum Scheduled Codes Power Headroom in use by the CM, in units of tenth dB. The value is provided by the CMTS in units of quarter dB through a TLV value in the RNG-RSP message and is rounded upward for this MIB object to the nearest tenth dB. A value of zero indicates the CMTS provided no Power Headroom.
TEN docsIfExt2CmtsCmMscStatusMeasuredSNR	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.5	TenthdB	read-only	The signal to noise ratio perceived for this cable modem on the upstream logical channel as of the last station maintenance.
TEN docsIfExt2CmtsCmMscStatusEffectiveSNR	1.3.6.1.4.1.4491.2.1.5.1.3.2.1.6	TenthdB	read-only	The signal to noise ratio estimated for this cable modem on the upstream logical channel, referenced to 64QAM modulation. It is defined as the measured SNR at the last station maintenance, minus the CM power shortfall, plus the Power Headroom, minus the constellation gain of the station maintenance burst. Note that the value of the object docsIfCmtsCmStatusSignalNoise will be identical to the value of this object when Maximum Scheduled Codes is enabled.
docsIfExt2CmtsUpChannelMscTable	1.3.6.1.4.1.4491.2.1.5.1.3.3		not-accessible	This table extends the docsIfUpstreamChannelTable to report CM MSC status.
docsIfExt2CmtsUpChannelMscEntry	1.3.6.1.4.1.4491.2.1.5.1.3.3.1		not-accessible	An entry for MSC upstream status report. Only SCDMA logical upstream channels (i.e., ifType=docsCableUpstreamChannel(205) and docsIfUpChannelType=scdma(3)) are included in this table.
INT docsIfExt2CmtsUpChannelMscState	1.3.6.1.4.1.4491.2.1.5.1.3.3.1.1	INTEGER	read-write	Indicates the state of the Maximum Scheduled Codes feature for an individual logical channel on the CMTS. The state will transition automatically from dormant(5) to ChannelEnabled(1) and vice-versa when the feature is globally enabled by the object docsIfExt2CmtsMscGlobalEnable. channelEnabled(1) S-CDMA Maximum Scheduled Codes is enabled in the UCD TLV-17. channelDisabled(2) S-CDMA Maximum Scheduled Codes is disabled in the UCD TLV-17 or a UCD has been sent that does not contain that TLV. Dormant(3) The CMTS channel is being set to channelEnabled(2) but MSC is globally disabled (docsIfExt2CmtsMscGlobalEnable is false(2) ). This value is explicitly read-only.
G32 docsIfExt2CmtsUpChannelMSCTotalCMsEx	1.3.6.1.4.1.4491.2.1.5.1.3.3.1.2	Gauge32	read-only	Total number of CMs with docsIfCmtsCmStatusValue of registrationComplete with MSC active.
U32 docsIfExt2CmtsUpChannelMSCLimitIUC1	1.3.6.1.4.1.4491.2.1.5.1.3.3.1.3	Unsigned32	read-only	Indicates that, in order to prevent CMs from exceeding MSC, the CMTS will limit the scheduling of broadcast IUC1 to at most this many SCDMA codes per SCMDA frame.
U32 docsIfExt2CmtsUpChannelMSCMinimumValue	1.3.6.1.4.1.4491.2.1.5.1.3.3.1.4	Unsigned32	read-write	When Maximum Scheduled Codes is enabled, instructs the CMTS to assign cable modems MSC values no less than this value.
docsIfExt2CmtsUpChannelTable	1.3.6.1.4.1.4491.2.1.5.1.3.4		not-accessible	This table extends the docsIfUpstreamChannelTable to report additional upstream status information.
docsIfExt2CmtsUpChannelEntry	1.3.6.1.4.1.4491.2.1.5.1.3.4.1		not-accessible	An entry for upstream status information.
G32 docsIfExt2CmtsUpChannelTotalCMs	1.3.6.1.4.1.4491.2.1.5.1.3.4.1.1	Gauge32	read-only	Total number of CMs with docsIfCmtsCmStatusValue of registrationComplete.
docsIfExt2Conformance	1.3.6.1.4.1.4491.2.1.5.2
docsIfExt2Compliances	1.3.6.1.4.1.4491.2.1.5.2.1
docsIfExt2Compliance	1.3.6.1.4.1.4491.2.1.5.2.1.1			The compliance statement for DOCSIS 20 enhanced features.
docsIfExt2Groups	1.3.6.1.4.1.4491.2.1.5.2.2
docsIfExt2CmGroup	1.3.6.1.4.1.4491.2.1.5.2.2.1			Group of objects implemented in Cable Modems.
docsIfExt2CmtsGroup	1.3.6.1.4.1.4491.2.1.5.2.2.2			Group of objects implemented in Cable Modem Termination Systems.

RFC description

Enhances DOCSIS 2.0 management with SCDMA code allocation and Maximum Scheduled Codes (MSC) configuration.

Start monitoring DOCSIS cable modem/CMTS (SCDMA/MSC extension, vendor-neutral CableLabs standard) 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 DOCS-IFEXT2-MIB