IEEE 802.5 Token Ring MIB
Extracted elements (26)
All timer objects in dot5TimerTable are defined as read-only, but implementors are explicitly encouraged to provide read-write access where possible and useful, while giving due consideration to the dangers of writable timers. This balances operational flexibility against the risk of misconfiguration.
The MacAddress textual convention has no effect on the syntax or encoding of managed objects; objects defined using it are encoded by the rules of their primitive type (OCTET STRING). No changes to the SMI or SNMP are required; the convention exists purely for human readers.
IEEE 802.5 (unlike other 802.x protocols) requires MAC addresses to be transmitted most significant bit first, but the MacAddress textual convention uses canonical (least significant bit first) order as defined by IEEE 802.1a. The convention has no effect on encoding; it is adopted for reader convenience only.
The testInsertFunc test inserts the station into the network when invoked and could therefore cause problems if the station is connected to an operational network. This is a caution for management systems invoking tests via ifExtnsTestTable.
Because all statistics use 32-bit Counter syntax but hardware may maintain 16-bit counters, the agent MUST read hardware counters frequently enough to prevent loss of significance in order to maintain accurate 32-bit software counters.
Systems having 802.5 interfaces MUST implement the dot5Table (Interface Table) and the dot5StatsTable (Statistics Table). Implementation of the dot5TimerTable is optional.
dot5ActMonParticipate (dot5Entry 8) is a read-write INTEGER true(1)/false(2) controlling whether the interface participates in active monitor selection. A change may not take effect until the next time the interface is opened.
dot5ChipSets (OID dot5 4) defines OBJECT IDENTIFIERs for known 802.5 hardware chip sets for use with ifExtnsChipSet from RFC 1229: chipSetIBM16 (IBM 16/4 Mb/s), chipSetTItms380 (TI 4 Mb/s), and chipSetTItms380c16 (TI 16/4 Mb/s).
dot5Commands (dot5Entry 2) is a read-write INTEGER supporting four values: no-op(1), open(2), reset(3), and close(4). Setting open causes the station to enter the open state; reset retains MIB counter values if possible; close removes the station from the ring. When read, always returns no-op(1).
dot5Functional (dot5Entry 9) is a read-write MacAddress bitmask of all Token Ring functional addresses for which this interface will accept frames.
dot5RingOpenStatus (dot5Entry 5) is a read-only INTEGER indicating the success or reason for failure of the most recent ring-entry attempt, with values: noOpen(1), badParam(2), lobeFailed(3), signalLoss(4), insertionTimeout(5), ringFailed(6), beaconing(7), duplicateMAC(8), requestFailed(9), removeReceived(10), open(11).
dot5RingSpeed (dot5Entry 6) is a read-write INTEGER indicating the ring's bandwidth: unknown(1), oneMegabit(2), fourMegabit(3), sixteenMegabit(4).
dot5RingStatus (dot5Entry 3) is a read-only INTEGER bitmask representing currently applicable ring conditions after a successful open. Defined values include: 0 (no problems), 32 (Ring Recovery), 64 (Single Station), 256 (Remove Received), 2048 (Lobe Wire Fault), 4096 (Transmit Beacon), 8192 (Soft Error), 16384 (Hard Error), 32768 (Signal Loss), 131072 (no status/open not completed).
dot5StatsFreqErrors (dot5StatsEntry 19) is an optional Counter tracking how often the incoming signal frequency differs from the expected frequency by more than the IEEE 802.5 standard allows.
dot5StatsHardErrors (dot5StatsEntry 12) counts the number of immediately recoverable fatal errors detected, corresponding to the number of times the interface is transmitting or receiving beacon MAC frames.
dot5StatsSoftErrors (dot5StatsEntry 11) counts the number of Soft Errors detected, directly corresponding to the number of Report Error MAC frames transmitted. Soft Errors are those recoverable by MAC-layer protocols.
dot5StatsTable (OID dot5 2) contains 802.5 statistics and error counters with one mandatory entry per interface. All statistics use Counter (32-bit wrap-around) syntax; nineteen error counters are defined including line errors, burst errors, AC errors, lost frame errors, soft errors, hard errors, signal loss, transmit beacons, recoveries, lobe wire faults, and removes.
dot5Table (OID dot5 1) is the 802.5 Interface Table containing state and parameter information specific to 802.5 interfaces, with one mandatory entry per interface. It is mandatory for all systems with 802.5 interfaces, in addition to the generic interfaces table.
dot5TimerNoToken (dot5TimerEntry 6) is the timeout used to recover from token-related error situations. Its normal value is dot5TimerReturnRepeat + N*dot5TimerHolding, where N is the maximum number of stations on the ring.
dot5TimerTable (OID dot5 5) is an optional group containing eleven 802.5 timer values per interface: ReturnRepeat, Holding, QueuePDU, ValidTransmit, NoToken, ActiveMon, StandbyMon, ErrorReport, BeaconTransmit, and BeaconReceive, all in units of 100 microseconds.
dot5UpStream (dot5Entry 7) is a read-only MacAddress holding the MAC address of the upstream neighbor station in the ring.
MacAddress is a textual convention defined as OCTET STRING (SIZE 6) representing a 6-octet MAC address in 'canonical' order (least significant bit first) as defined by IEEE 802.1a. 16-bit addresses are represented by setting the upper 4 octets to zero.
testInsertFunc (OID dot5Tests 1) is an 802.5-specific interface test identifier for use with ifExtnsTestTable from RFC 1229. Invoking it tests the insert-ring logic of the hardware when connected to a wiring concentrator; it actually inserts the station into the network and could disrupt operational rings.
The MIB module root is dot5 OBJECT IDENTIFIER ::= { experimental 4 }, registered under the experimental namespace. This value is also used as the value of ifSpecific in MIB-II for interfaces of type iso88025-tokenRing(9).
The RFC explicitly states that security issues are not discussed in this memo. No authentication, access control, or threat analysis is provided for the managed objects defined.
dot5RingState (dot5Entry 4) tracks the interface state with respect to ring membership: opened(1), closed(2), opening(3), closing(4), openFailure(5), ringFailure(6). Transitions are triggered by dot5Commands (open/close/reset) and by ring error conditions.