Definitions of Managed Objects for RS-232-like Hardware Devices using SMIv2
obsoletes
- rfc-1317 — Definitions of Managed Objects for RS-232-like Hardware Devices
Extracted elements (23)
rs232PortIndex is defined to map directly to external hardware connectors where possible, and its value must remain constant across agent re-initializations to provide stable management references.
rs232SyncPortRTSCTSDelay (milliseconds the DCE must wait after seeing RTS before asserting CTS) exists specifically to support older synchronous devices that cannot recognize CTS within a certain interval after asserting RTS.
The Interface MIB's ifTestTable and ifRcvAddressTable are not relevant to the RS-232-like MIB. Usefulness of error counters in this MIB depends on the octet counters in ifFixedLengthGroup.
The RS-232-like MIB requires conformance groups ifGeneralGroup and ifFixedLengthGroup from the Interface MIB; the value of ifSpeed must equal rs232PortOutSpeed. The MIB applies to ifType values rs232(33), v35(45), and possibly others.
The compliance statement requires rs232Group for all SNMPv2 entities with RS-232-like interfaces; rs232AsyncGroup is mandatory only for entities with asynchronous interfaces, and rs232SyncGroup only for those with synchronous interfaces.
The RS-232-like Hardware Device MIB is mandatory for all systems that have such a hardware port supporting services managed through some other MIB.
Asynchronous error counters rs232AsyncPortParityErrs, rs232AsyncPortFramingErrs, and rs232AsyncPortOverrunErrs are read-only Counter32 objects counting errors since system re-initialization while port state was 'up' or 'test'.
rs232AsyncPortAutobaud is a read-write INTEGER (enabled/disabled) controlling automatic input-speed sensing; when enabled, observed speed, parity, and character-size values may temporarily differ from configured values.
rs232AsyncPortTable contains asynchronous-port-specific parameters indexed by rs232AsyncPortIndex; fields include rs232AsyncPortBits (5..8), rs232AsyncPortStopBits (one/two/oneAndHalf/dynamic), rs232AsyncPortParity (none/odd/even/mark/space), rs232AsyncPortAutobaud, and three error counters.
rs232InSigTable and rs232OutSigTable monitor up to 11 hardware control signals per port — rts, cts, dsr, dtr, ri, dcd, sq, srs, srts, scts, sdcd — with current state (none/on/off) and a Counter32 of state changes, as defined in EIA RS-232-C.
rs232Number is a read-only Integer32 scalar giving the total number of ports (regardless of current state) in the RS-232-like general port table.
rs232PortInFlowType and rs232PortOutFlowType are read-write INTEGERs specifying hardware flow control: none(1), ctsRts(2), or dsrDtr(3).
rs232PortInSpeed and rs232PortOutSpeed are read-write Integer32 objects giving the port's input and output speed in bits per second; non-standard values such as 9612 are probably not allowed on most implementations.
rs232PortTable is the general port table indexed by rs232PortIndex (InterfaceIndex); each entry carries type, input/output signal counts, input/output speeds, and input/output flow control type.
rs232PortType is a read-only INTEGER enumerating the port hardware type: other(1), rs232(2), rs422(3), rs423(4), v35(5), x21(6).
rs232SyncPortClockSource is a read-write INTEGER: internal(1), external(2), or split(3), where 'split' means transmit clock is internal and receive clock is external.
rs232SyncPortEncoding is a read-write INTEGER selecting bit-stream encoding: nrz(1) for Non-Return to Zero or nrzi(2) for Non-Return to Zero Inverted; default is nrz.
rs232SyncPortMinFlags is a read-write Integer32 (default 2) specifying the minimum number of flag patterns the port needs to recognize the end of one frame and the start of the next; plausible values are 1 and 2.
rs232SyncPortMode is a read-write INTEGER specifying data transfer direction: fdx(1), hdx(2), simplex-receive(3), or simplex-send(4); default is fdx.
rs232SyncPortRole is a read-write INTEGER — dte(1) or dce(2), default dce — indicating whether the device acts as data terminal equipment or data circuit-terminating equipment on this port.
rs232SyncPortRTSControl is a read-write INTEGER (controlled/constant, default constant) specifying whether the device asserts RTS only when transmitting or holds it asserted continuously; in controlled mode, DTE waits for CTS from DCE before transmitting.
rs232SyncPortTable contains synchronous-port-specific parameters including clock source, frame-check errors, transmit-underrun errors, receive-overrun errors, interrupted frames, aborted frames, and SDLC-specific fields (role, encoding, RTS control, RTS-CTS delay, mode, idle pattern, min flags).
The RFC explicitly states that security issues are not discussed in this memo.