IEEE 802.5 MIB using SMIv2
Extracted elements (25)
dot5RingSpeed reflects the speed configured for the next insertion rather than the current operational speed (ifSpeed). When set to unknown(1), the ring's actual ring-speed is used at insertion time. This separation allows pre-configuration of speed changes without disrupting the current ring session.
MAC addresses in this MIB use the MacAddress textual convention in IEEE 802.1a 'canonical' order (least significant bit first), even though 802.5 requires transmission most significant bit first. This ensures consistency with other MAC-address representations across MIB modules, at the cost of a bit-order translation relative to the wire.
The dot5Commands open(2) and close(4) values correspond to MIB-II's ifAdminStatus up(1) and down(2) values; setting either dot5Commands or ifAdminStatus affects the value of the other. This linkage was clarified from RFC 1231 to avoid ambiguity in dual-path management.
For functional addresses on an 802.5 interface, only one ifRcvAddressTable entry is required: the entry whose ifRcvAddressAddress is the logical AND of the functional address bit with the bitmask of all functional addresses the interface accepts. The format matches ifPhysAddress.
ifPhysAddress for an 802.5 interface must contain the IEEE MAC address as a 6-octet string in IEEE 802.1a canonical order, with the Group Bit positioned as the low-order bit (0x01) of the first octet. This applies regardless of 802.5's on-wire MSB-first transmission order.
The dot5TimerTable is designated obsolete in RFC 1743 but its definition is retained for backward compatibility with RFC 1231 implementations. New implementations should not implement this table.
This MIB applies to interfaces where ifType equals iso88025-tokenRing(9). The 802.5 module does not preclude sub-layers above or below the 802.5 interface, but such layering is not typical. 802.5 does not support virtual circuits.
When used with the pre-RFC 1573 interfaces group, an 802.5 interface maps one-to-one to an interface in RFC 1213 MIB-II: the ifIndex value for an 802.5 interface directly identifies corresponding instances of objects defined in this MIB.
If an interface's hardware maintains statistics in 16-bit counters, the agent must read the hardware's counters frequently enough to prevent loss of significance in order to maintain 32-bit counters in software.
SNMPv2 entities implementing the IEEE 802.5 MIB must implement the dot5StateGroup and dot5StatsGroup as mandatory groups. Write access to dot5ActMonParticipate and dot5Functional is not required (MIN-ACCESS read-only).
dot5ActMonParticipate is a read-write INTEGER (true(1)/false(2)) controlling whether the interface participates in active monitor selection. Write access is not required per the compliance statement. A change does not take effect until the next Active Monitor election, and might not take effect until the next interface open.
dot5Commands is a read-write INTEGER with values noop(1), open(2), reset(3), and close(4) that controls ring interface state. Setting open(2) causes the station to enter the open state; close(4) removes the station from the ring; reset(3) resets the station while retaining MIB counter values if possible. When read, always returns noop(1).
dot5Functional is a read-write MacAddress representing the bitmask of all Token Ring functional addresses for which the interface will accept frames. Write access is not required per the compliance statement.
dot5LastBeaconSent is a read-only TimeStamp recording the value of sysUpTime at which the local system last transmitted a Beacon frame on the interface. This object was newly added in RFC 1743 relative to RFC 1231.
dot5RingOpenStatus is a read-only INTEGER indicating success or reason for failure of the station's most recent ring-insertion attempt. Values include noOpen(1), badParam(2), lobeFailed(3), signalLoss(4), insertionTimeout(5), ringFailed(6), beaconing(7), duplicateMAC(8), requestFailed(9), removeReceived(10), and open(11) for success.
dot5RingSpeed is a read-write INTEGER specifying the ring speed at the next insertion: unknown(1), oneMegabit(2), fourMegabit(3), or sixteenMegabit(4). It reflects the speed for the next insertion, which may differ from the current operational speed given by ifSpeed. Interfaces that do not support changing ring speed can only be set to their current value.
dot5RingStatus is a read-only INTEGER (0..262143) representing a bitmask of currently applicable ring conditions, including Ring Recovery (32), Single Station (64), Remove Received (256), Auto-Removal Error (1024), Lobe Wire Fault (2048), Transmit Beacon (4096), Soft Error (8192), Hard Error (16384), Signal Loss (32768), and no-status/open-not-completed (131072).
dot5StatsFrameCopiedErrors is a Counter32 incremented when a station recognizes a frame addressed to its specific address and detects that the FS field A bits are already set to 1, indicating a possible line hit or duplicate MAC address on the ring.
dot5TestFullDuplexLoopBack (dot5Tests 2) is an OBJECT-IDENTITY for use with ifTestTable to test the path from memory through the chip set's internal logic and back to memory, verifying proper functioning of the system's interface to the chip set.
dot5TestInsertFunc (dot5Tests 1) is an OBJECT-IDENTITY for use with ifTestTable to test the insert ring logic of the hardware when a lobe media cable is connected to a wiring concentrator. Invoking it inserts the station into the network, which may disrupt operational rings.
The dot5ChipSets subtree defines OBJECT-IDENTIFIERs for Token Ring hardware chip sets retained for backward compatibility with RFC 1229's ifExtnsChipSet object (obsoleted by RFC 1573): dot5ChipSetIBM16 (IBM 16/4 Mbps), dot5ChipSetTItms380 (TI TMS380 4 Mbps), and dot5ChipSetTItms380c16 (TI TMS380C16 16/4 Mbps).
The dot5StatsTable contains 18 Counter32 statistics per 802.5 interface, covering line errors, burst errors, AC errors, abort transmit errors, internal errors, lost frame errors, receive congestions, frame copied errors, token errors, soft errors, hard errors, signal loss, transmit beacons, recoveries, lobe wire faults, removes, singles, and frequency errors.
The dot5Table (802.5 Interface Table) contains state and parameter information specific to 802.5 interfaces, with one entry per interface. Mandatory for all systems having 802.5 interfaces, in addition to the ifTable. Fields include dot5Commands, dot5RingStatus, dot5RingState, dot5RingOpenStatus, dot5RingSpeed, dot5UpStream, dot5ActMonParticipate, dot5Functional, and dot5LastBeaconSent.
The RFC explicitly states that security issues are not discussed in this memo. No authentication, access control, or privacy mechanisms are specified for the managed objects defined herein.
dot5RingState defines six states for an 802.5 interface with respect to ring membership: opened(1), closed(2), opening(3), closing(4), openFailure(5), and ringFailure(6). Transitions are triggered by dot5Commands (open/close) and ring events such as lobe faults or beaconing failures.