ATM-Based xDSL Bonded Interfaces MIB
Extracted elements (24)
Performance monitoring counters are not reset when a GBS is re-initialized, but only when the agent itself is reset or re-initialized. This preserves historical performance data across link-layer restarts, which is important for SLA and trend analysis.
The MIB is structured as an extension to GBOND-MIB rather than a standalone module, placing only ATM-specific objects (differential delay tolerance, lost cell counts) in G9981-MIB while reusing GBOND-MIB for generic bonding management. This avoids duplication and follows the RFC 4181 modular structure recommendation.
The TR-159 mapping from managed objects to SNMP objects is not always one-to-one; g9981PortPm* objects partially map to aGroupPerf* TR-159 attributes because there are no dedicated TR-159 PM attributes for them, as their definition is identical to GBOND-MIB gBondPortPm* objects.
Compliance with G9981-MIB requires compliance with two external compliance statements: IF-MIB ifCompliance3 and GBOND-MIB gBondCompliance. The G9981-MIB only defines ATM-specific extensions; generic GBS port configuration, capabilities, status, and PM are in GBOND-MIB.
The ATM-MIB (RFC 2515) can be used alongside G9981-MIB to manage the ATM aspects of a G.Bond/ATM port; G9981-MIB does not replace or subsume ATM-MIB functionality.
Deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, SNMPv3 with cryptographic security is RECOMMENDED. Implementations SHOULD provide the security features described by the SNMPv3 framework.
Entries in g9981PortConfTable MUST be maintained in a persistent manner. Entries in the 15-minute and 1-day PM history tables likewise MUST be maintained persistently.
If a 15-minute or 1-day PM history bucket is marked invalid (g9981PortPm15MinIntervalValid or g9981PortPm1DayIntervalValid is false), the BTU MUST NOT produce notifications based upon the value of counters in that bucket.
Implementations claiming compliance to the SNMPv3 standard MUST include full support for authentication and privacy via the User-based Security Model (USM) with the AES cipher algorithm (RFC 3826).
PM counters for RxLostCells are inhibited (counting stops) during Severely Errored Seconds (SES) or Unavailable Seconds (UAS); TxLostCells, upstream and downstream differential delay PM counters are inhibited during Unavailable Seconds (UAS) only.
Reads or writes to g9981PortConfUpDiffDelayTolerance, g9981PortConfDnDiffDelayTolerance, g9981PortStatTxLostCells, g9981PortStatMaxUpDiffDelay, and g9981PortStatMaxDnDiffDelay on GBS-R ports MUST be rejected with SNMP error inconsistentValue, as these objects are irrelevant to the remote CPE side.
The agent SHOULD align the beginning of each 15-minute performance monitoring interval to a fifteen-minute boundary of a wall clock, and the beginning of each one-day interval SHOULD be aligned with the start of a day.
The G9981-MIB module MUST be used in conjunction with the GBOND-MIB module, which is common to all G.Bond technologies. Both modules are REQUIRED to manage a G.Bond/ATM port.
The g9981UpDiffDelayToleranceExceeded and g9981DnDiffDelayToleranceExceeded notifications MAY be sent for GBS-C ports when the port is 'up', on crossing events in both directions; generation is controlled by g9981PortConfDiffDelayToleranceExceededEnable. These notifications are not applicable to GBS-R ports.
g9981PortConfTable provides read-write configuration for G.Bond/ATM ports, indexed by ifIndex, containing three objects: g9981PortConfUpDiffDelayTolerance (0..2047 ms), g9981PortConfDnDiffDelayTolerance (0..2047 ms), and g9981PortConfDiffDelayToleranceExceededEnable (TruthValue). These objects are only applicable to GBS-C ports.
g9981PortPm15MinTable stores up to 96 historical 15-minute PM buckets per port (indexed by ifIndex and g9981PortPm15MinIntervalIndex 1..96), containing monitored time, RxLostCells, TxLostCells, upstream and downstream differential delay per interval, plus a TruthValue validity flag. Intervals 2..96 are OPTIONAL. Entries MUST be persistent.
g9981PortPm1DayTable stores up to 7 historical 1-day PM buckets per port (indexed by ifIndex and g9981PortPm1DayIntervalIndex 1..7), mirroring the 15-minute structure with monitored seconds, lost cell counts, and differential delay values per day. Intervals 2..7 are OPTIONAL. Entries MUST be persistent.
g9981PortPmCurTable provides current Performance Monitoring data for G.Bond/ATM ports covering both 15-minute and 1-day intervals, including valid/invalid interval counts, elapsed time, RxLostCells, TxLostCells, upstream and downstream differential delay (all in HCPerfCurrentCount). This table is NOT persistent.
g9981PortStatTable provides read-only live status for G.Bond/ATM ports with four Counter32/Unsigned32 objects: g9981PortStatRxLostCells (ATM cells lost in receive direction), g9981PortStatTxLostCells (peer-detected cells lost in transmit direction, GBS-C only), g9981PortStatMaxUpDiffDelay, and g9981PortStatMaxDnDiffDelay (both in units of 0.1 ms). This table is NOT persistent.
The MilliSeconds TEXTUAL-CONVENTION is defined as Unsigned32 with DISPLAY-HINT 'd', used to represent time values in milliseconds for differential delay tolerance configuration objects.
Two NOTIFICATION-TYPEs are defined: g9981UpDiffDelayToleranceExceeded (OID .1) and g9981DnDiffDelayToleranceExceeded (OID .2), each carrying the applicable tolerance threshold and current maximum differential delay as varbinds, mapping to TR-159 notifications nIMAUpDiffDelayToleranceExceeded and nIMADownDiffDelayToleranceExceeded respectively.
IANA assigned OID 208 under the mib-2 transmission sub-tree to the g9981MIB MODULE-IDENTITY for the G.Bond/ATM MIB module.
Readable objects in the MIB collectively expose interface performance data and configuration aspects; GET and NOTIFY access should be controlled and object values SHOULD be encrypted when sent over the network via SNMP. SNMPv3 with USM/AES is required; Transport Security Model (TSM) with SSH or TLS/DTLS may also be used.
Unauthorized SET operations on g9981PortConfTable objects (differential delay tolerances, notification enable) can cause SLA breaches by increasing traffic delay or suppressing differential delay threshold notifications. These read-write objects require protection in non-secure environments.