Definitions of managed objects for the DS3 Interface type
obsoleted by
- rfc-1407 — Definitions of Managed Objects for the DS3/E3 Interface Type
updated by
- rfc-1239 — Reassignment of experimental MIBs to standard MIBs
Extracted elements (28)
Although the objects in the DS3 Configuration Group are defined as read-only, the specification notes that agents may at their discretion make them read-write so that an authorized management station can change CSU behavior, such as placing the device into a loopback state.
The ds3Index object in the configuration table explicitly ties each CSU to the corresponding ifIndex in MIB-II, ensuring the DS3 MIB module integrates with the standard interface table rather than defining a parallel indexing scheme.
The MIB was intentionally scoped to objects that can generally be read from deployed CSUs (both in-chassis and external via proxy), rather than attempting to manage multiplexors, DSUs, and other equipment. This up-front design decision closely aligned the MIB with operationally available data.
Controlled Slip Seconds (CSS) is only supported on SYNTRAN interfaces. Agents configured with non-SYNTRAN interfaces may treat ds3IntervalCSSs, ds3CurrentCSSs, and ds3TotalCSSs as having an ACCESS clause value of not-accessible.
M23 and ClearChannel DS3 interfaces do not support the ds3Loopback managed object; agents on such interfaces must always return ds3NoLoop.
When a 10-or-more-second UAS transition period crosses a 900-second statistics window boundary, successive GETs of ds3IntervalSES and ds3IntervalUAS will return differing values. This is an unavoidable side-effect of the presently defined managed objects.
Each agent residing on a host that uses DS3 interfaces is required to assign a small, positive integer (CSUIndex) uniquely to each CSU to distinguish between different CSUs attached to a node.
Implementation of the DS3 Configuration Group (ds3ConfigTable) is mandatory for all systems that attach to a DS3 Interface.
Implementation of the DS3 Current Group (ds3CurrentTable) is mandatory for all systems that attach to a DS3 Interface.
Implementation of the DS3 Interval Group (ds3IntervalTable) is mandatory for all systems that attach to a DS3 interface.
Implementation of the DS3 Total Group (ds3TotalTable) is mandatory for all systems that attach to a DS3.
Coding Violation (CV) for DS3 is a P-bit Parity Error event. For C-Bit Parity applications it also includes CP-Bit parity violations; for SYNTRAN applications it also includes received CRC-9 code mismatches. Bipolar Violations (BPV) for B3ZS-coded signals are violations not part of a zero-substitution code.
ds3CircuitIdentifier (ds3ConfigEntry 11) is a DisplayString of SIZE(0..255) containing the transmission vendor's circuit identifier, used to facilitate troubleshooting.
ds3ConfigTable (OID ds3 1) is the DS3 Configuration table indexed by ds3CSUIndex, containing configuration and status objects: LineType, ZeroCoding, Loopback, SendCode, YellowAlarm, RedAlarm, and CircuitIdentifier.
ds3CurrentTable (OID ds3 3) contains statistics being collected for the current 15-minute interval, with the same seven error counters (ESs, SESs, SEFSs, UASs, CSSs, BPVs, CVs) as the Interval table.
ds3IntervalTable (OID ds3 2) is indexed by ds3IntervalIndex and ds3IntervalNumber (1..96, where 1 is the most recent completed 15-minute interval). It contains per-interval counters: ESs, SESs, SEFSs, UASs, CSSs, BPVs, and CVs.
ds3LineType (ds3ConfigEntry 5) indicates the variety of DS3 C-bit application: ds3M23, ds3SYNTRAN, ds3CbitParity, ds3ClearChannel, or other. The line type affects interpretation of usage and error statistics; all operate at 44.736 Mbps.
ds3Loopback (ds3ConfigEntry 7) represents the loopback state of the CSU with five values: ds3NoLoop, ds3LocalLoopbackLocalSide, ds3LocalLoopbackRemoteSide, ds3RemoteLoopbackLocalSide, and ds3RemoteLoopbackRemoteSide. Devices supporting read/write access should return badValue for unsupported loopback states.
ds3SendCode (ds3ConfigEntry 8) indicates the type of code being sent across the DS3 circuit by the CSU: ds3SendTestMessage, ds3SendNoCode, ds3SendSetCode, ds3SendLoopbackCode, or ds3SendResetCode.
ds3TimeElapsed (ds3ConfigEntry 3) is an INTEGER(1..900) indicating the number of seconds, including partial seconds, elapsed since the beginning of the current error-measurement period.
ds3TotalTable (OID ds3 4) contains the cumulative sum of error statistics for the 24-hour interval preceding the first valid interval in the DS3CurrentTable, with the same seven counter types.
ds3ValidIntervals (ds3ConfigEntry 4) is an INTEGER(0..96) indicating the number of previous 15-minute intervals for which valid data was collected; the value is 96 unless the CSU was brought online within the last 24 hours.
ds3ZeroCoding (ds3ConfigEntry 6) describes the zero-code suppression method used on the DS3 link, with defined values ds3other(1) and ds3B3ZS(2). B3ZS uses specified patterns of normal bits and bipolar violations to replace sequences of zero bits.
Errored Seconds (ES) is defined as a second with one or more Coding Violations, one or more Out of Frame events, or an AIS. Severely Errored Seconds (SES) is a second with 44 or more Coding Violations, one or more OOF events, or an AIS.
Out of Frame (OOF) is detected when any three or more errors occur in sixteen or fewer consecutive F-bits within a DS3 M-frame, and is cleared when reframe occurs. Loss of Signal (LOS) is declared upon observing 175 +/- 75 contiguous pulse positions with no pulses.
Red Alarm is declared after detecting a Loss of Signal, a persistent OOF event, or an AIS for at least 2-10 seconds; it is cleared at the onset of 10 consecutive seconds with no SES. Yellow Alarm is declared after detecting the Yellow Signal per ANSI T1.107-1989.
Unavailable Seconds (UAS) are counted when the CSU is in the Unavailable Signal State (Red or Yellow Alarm), including the initial 10 seconds to enter the state but not the 10 seconds to exit. Seconds counted as UAS may not also be counted as ES or SES.
Security issues are not discussed in this memo. The document provides no authentication, authorization, or access control guidance for DS3 MIB objects.