FAST-ETHERNET-MIB

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Category: Network Interfaces, Technology: Switching/L2

Description: MIB defining management objects for Fast Ethernet (100BASE-T) interfaces, extending standard Ethernet MIB with 100Mbps-specific attributes.

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What Is FAST-ETHERNET-MIB?

This MIB defines management objects for Fast Ethernet (100BASE-T) interfaces, extending the base Ethernet-like interface model with attributes specific to 100 Mbps auto-negotiation and port-group organization; the ct-prefixed object names point to a Cabletron/Enterasys-style private implementation rather than a formal IETF standard. It exposes per-port configuration and negotiation data organized by port group and port, including locally supported technology abilities, the currently negotiated operational mode, and the technology abilities advertised to and received from the link partner. Its monitoring value is centered on link negotiation health — ctFastEthernetCurrentOperationalMode reveals whether a port has actually negotiated full-duplex 100Mbps versus falling back to a lower/half-duplex mode, and comparing ctFastEthernetAdvertisedTechnologyAbility against ctFastEthernetReceivedTechnologyAbility helps diagnose auto-negotiation mismatches between two connected devices. It complements (and is expected to be used alongside) the standard IETF Ethernet-like MIB (dot3) and IF-MIB, since it only adds Fast-Ethernet-specific negotiation detail rather than duplicating basic interface counters. It is typically deployed on managed Ethernet switches with 100BASE-T ports where administrators need to confirm auto-negotiation outcomes and diagnose duplex mismatches. Engineers can download the FAST-ETHERNET-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in FAST-ETHERNET-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

managed Ethernet switch with 100BASE-T (Fast Ethernet) ports, likely Cabletron/Enterasys-derived implementation

Monitoring Examples

An admin would poll ctFastEthernetCtlTable/ctFastEthernetCtlEntry, indexed by ctFastEthernetCtlPortGroup and ctFastEthernetCtlPort, to read ctFastEthernetCurrentOperationalMode and confirm whether a given port is running at 100Mbps full-duplex as expected. Comparing ctFastEthernetAdvertisedTechnologyAbility against ctFastEthernetReceivedTechnologyAbility on a suspect port reveals an auto-negotiation mismatch — a common cause of unexpected half-duplex operation. ctFastEthernetCtlTableNumEntries gives a quick count of managed Fast Ethernet ports, and ctMMACFENBCfgTable/Entry covers related multi-MAC configuration for those ports.

What Can Be Monitored

current operational (speed/duplex) mode
locally supported technology abilities
advertised technology abilities
received technology abilities from link partner
Fast Ethernet port count

Imported Objects

From CTRON-MIB-NAMES

ctFastEthernet

OBJECT-IDENTITY

From RFC-1212

OBJECT-TYPE

OIDs

OID symbolic	OID numeric	Type	Access	Description
ctFastEthernetCtl	1.3.6.1.4.1.52.4.1.2.9.1
ctFastEthernetCtlTable	1.3.6.1.4.1.52.4.1.2.9.1.1		not-accessible	Provides a list of definitions and control objects over 100Base-X ports.
ctFastEthernetCtlEntry	1.3.6.1.4.1.52.4.1.2.9.1.1.1		not-accessible	Defines a particular entry containing objects pertaining to definition and control over 100Base-X ports.
INT ctFastEthernetCtlInterface	1.3.6.1.4.1.52.4.1.2.9.1.1.1.1	INTEGER	read-only	The interface for which this fast ethernet information pertains.
INT ctFastEthernetCtlPortGroup	1.3.6.1.4.1.52.4.1.2.9.1.1.1.2	INTEGER	read-only	The port group for which this fast ethernet information pertains.
INT ctFastEthernetCtlPort	1.3.6.1.4.1.52.4.1.2.9.1.1.1.3	INTEGER	read-only	The physical port for which this fast ethernet information pertains.
INT ctFastEthernetLocalTechnologyAbility	1.3.6.1.4.1.52.4.1.2.9.1.1.1.4	INTEGER	read-only	This indicates the technology ability of the local hardware. The value of this object is the logical OR of all supported technologies. Where each technology is given the values below: other(1) Undefined, or ability not known Auto-Negotiation(2) Auto-Negotiation 10BASE-T(8) 10BASE-T 10BASE-TFD(16) Full duplex 10BASE-T 100BASE-TX(32) 100BASE-TX 100BASE-TXFD(64) Full Duplex 100BASE-TX 100BASE-T4(128) 100BASE-T4 100BASE-FX(256) 100BASE-FX 100BASE-FXFD(512) Full Duplex 100Base-FX For example a port which supported 100Base-TX(32), 100Base-TXFD(64), and Auto-Negotiation(2) would have a value of 98(32 + 64 + 2).
INT ctFastEthernetCurrentOperationalMode	1.3.6.1.4.1.52.4.1.2.9.1.1.1.5	INTEGER	read-write	Indicates the current operational mode of this port. The value of this object is the logical OR of current opertational mode and how we arrived at that mode, whether it be by Auto-Negotiation(2), Manual-Config(4) or default. Where each mode is given the values below: other(1) Initializing or no link, ability unknown Auto-Negotiation(2) Auto-Negotiation/Parallel Detection Manual-Config(4) Manually Configured 10BASE-T(8) 10BASE-T 10BASE-TFD(16) Full duplex 10BASE-T 100BASE-TX(32) 100BASE-TX 100BASE-TXFD(64) Full Duplex 100BASE-TX 100BASE-T4(128) 100BASE-T4 100Base-FX(256) 100Base-FX 100Base-FXFD(512) Full Duplex 100Base-FX For example, a port operating at 100Base-TX(32) achieved through Auto-Negotiation(2) would have a value of 34(32 + 2). If the port was manually configured(4) for 100Base-TX(32) this object would have a value of 36(32 + 4). Values written to this object are limited to values read from ctFastEthernetLocalTechnologyAbility, with the addition of Manual-Config(4) but excluding other(1). Therefore if ctFastEthernetLocalTechnologyAbility has a value of 98 writing a value of 256 would result in an error. That is to say 100Base-FX is not supported on this port. A set to a value of Auto-Negotiation(2) will result in auto-negotiation being enabled and will cause link re-negotiation. Note: this re-negotiation will in every case cause temporary link loss during the link re-negotiation. Any other set with Auto-Negotiation(2) included will result in an error since you can not force an operational mode and auto-negotiation at the same time. A set to a value of Manual-Config(4) will result in auto-negotiation being disabled but the port staying at its current operational mode until device reset/power down at which time the port will come up in default mode. A subsequent read will indicate only the current operational mode achieved by default means. A set to any other value (port is being manually configured) must reflect a single ability. For example writing a value of 68 would result in auto-negotiation being disabled and the port being manually configured(4) for 100Base-TXFD(64). However a write of 100 would result in an error.
INT ctFastEthernetAdvertisedTechnologyAbility	1.3.6.1.4.1.52.4.1.2.9.1.1.1.6	INTEGER	read-write	Indicates the advertised ability of the local hardware, but only becomes active on ports that have auto-negotiation enabled. For example a port which will advertise 100Base-TX(32) and 100Base-TXFD(64) ablilities would have a value of 96(32 + 64). A port that does not support auto-negotiation will be read as other(1). Values written to this object are limited to values read from ctFastEthernetLocalTechnologyAbility, excluding other(1) and Auto-Negotiation(2). Therefore if ctFastEthernetLocalTechnologyAbility has a value of 98 writing a value of 128 would result in an error. That is to say 100Base-T4 is not supported on this port. Furthermore, if ctFastEthernetLocalTechnologyAbility has a value that does not include Auto-Negotiation(2), writing any value will result in an error. That is to say that this port does not support Auto-Negotiation and therefore does not support ctFastEthernetAdvertisedTechnologyAbility. A successful set operation will result in immediate link re-negotiation if ctFastEthernetCurrentOperationalMode has a value that includes Auto-Negotiation(2)(meaning Auto-negotiation is enabled). Note: this re-negotiation will in every case cause temporary link loss during the link re-negotiation. If set to a value that is incompatible with ctFastEthernetReceivedTechnologyAbility, link negotiation will not be successful and will cause permanent link loss.
INT ctFastEthernetReceivedTechnologyAbility	1.3.6.1.4.1.52.4.1.2.9.1.1.1.7	INTEGER	read-only	Indicates the advertised ability of the remote hardware, or link partner. The value of this object is the logical OR of all supported technologies. Where each technology is given the values below: other(1) Undefined Auto-Negotiation(2) Auto-Negotiation/Parallel Detection Not-Detected(4) Link Partner does not support Auto-Negotiation 10BASE-T(8) 10BASE-T 10BASE-TFD(16) Full duplex 10BASE-T 100BASE-TX(32) 100BASE-TX as defined in clause 25 100BASE-TXFD(64) Full Duplex 100BASE-TX 100BASE-T4(128) 100BASE-T4 as defined in clause 23 100Base-FX(256) 100Base-FX 100Base-FXFD(512) Full Duplex 100Base-FX For example a port which supports 100Base-TX(32), 100Base-TXFD(64), would have a value of 98(32 + 64 + Auto-Negotiation(2)). A read should always include Auto-Negotiation(2), unless the link partner does not support auto-negotiation, at which time the value will be Not-Detected(4) or auto-negotiation is disabled(or not supported) for this port at which time the value will be other(1).
INT ctFastEthernetCtlTableNumEntries	1.3.6.1.4.1.52.4.1.2.9.1.2	INTEGER	read-only	The number of entries in the ctFastEthernetCtl Table.
ctMMACFENBCfg	1.3.6.1.4.1.52.4.1.2.9.2
ctMMACFENBCfgTable	1.3.6.1.4.1.52.4.1.2.9.2.1		not-accessible	A table defining the capabilities of each port in regards to the MMAC Fast Ethernet Network Bus.
ctMMACFENBCfgEntry	1.3.6.1.4.1.52.4.1.2.9.2.1.1		not-accessible	defines a particular entry containing port configuration information.
INT ctMMACFENBCfgInterface	1.3.6.1.4.1.52.4.1.2.9.2.1.1.1	INTEGER	read-only	The interface for which this MMAC FENB information pertains.
INT ctMMACFENBCfgPortGroup	1.3.6.1.4.1.52.4.1.2.9.2.1.1.2	INTEGER	read-only	The port group for which this MMAC FENB information pertains.
INT ctMMACFENBCfgPort	1.3.6.1.4.1.52.4.1.2.9.2.1.1.3	INTEGER	read-only	The physical port for which this MMAC FENB information pertains.
INT ctMMACFENBOperCapabilities	1.3.6.1.4.1.52.4.1.2.9.2.1.1.4	INTEGER	read-only	This value indicates the current capabilities of this port. (1) Other (2) MMAC A Channel (4) MMAC FENB 1 (FENB= Fast Ethernet Network Bus) (8) MMAC FENB 2 (16) MMAC FENB 3 (32) Front Panel The value of this object is the logical OR of all supported capabilities.
INT ctMMACFENBAdminCapabilities	1.3.6.1.4.1.52.4.1.2.9.2.1.1.5	INTEGER	read-write	This value indicates the desired operational capabilities of this port. (1) Other (2) MMAC A Channel (4) MMAC FENB 1 (FENB= Fast Ethernet Network Bus) (8) MMAC FENB 2 (16) MMAC FENB 3 (32) Front Panel

RFC description

Cabletron Fast Ethernet MIB providing control and monitoring for 100Base-X ports and management capabilities.

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Download FAST-ETHERNET-MIB

What Is FAST-ETHERNET-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

RFC description