Definitions of Managed Objects for the SIP Interface Type
obsoleted by
- rfc-1694 — Definitions of Managed Objects for SMDS Interfaces using SMIv2
Extracted elements (27)
Although ipOverSMDSTable objects are specified as read-only, the MIB notes that at the agent's discretion they may be made read-write so an authorized management station can change IP subnetwork addressing configuration. This flexibility accommodates operational reconfiguration of LIS mappings without requiring a new MIB revision.
Managed objects for DS1 and DS3 interfaces underlying SIP (the physical layer) are explicitly excluded from this MIB and delegated to RFC 1232 and RFC 1233 respectively. This document covers only the SIP-specific protocol levels (L2, L3, PLCP) to avoid duplication.
Subscription and SNI configuration objects are explicitly excluded from this MIB and delegated to the separate 'Definitions of Managed Objects for SMDS Subscription' document. Destination Address Screening violations are also excluded from several error counters with a pointer to that module.
One SMDS individual address may be associated with multiple IP addresses, and one SNI may be associated with multiple Logical IP Subnetworks (LISs). The ipOverSMDSTable is indexed by both interface number and IP address to represent these many-to-many relationships.
The SIP interface type is identified by ifType value 31 (sip) in MIB-II, and ifSpecific must be set to the OBJECT IDENTIFIER sip ::= { transmission 31 }. All index objects (sipL3Index, sipL2Index, etc.) carry the same value as ifIndex for the corresponding interface.
Implementation of the SIP Error Log group (sipL3PDUErrorTable) is mandatory for all systems that implement SIP Level 3.
Implementation of the SIP Level 2 group is mandatory for all systems implementing SIP Level 2. The sipL2Table contains SIP L2PDU parameters and state variables, one entry per SIP port.
Implementation of the SIP Level 3 group is mandatory for all systems implementing SIP Level 3. The sipL3Table contains SIP L3 parameters and state variables, one entry per SIP port.
Implementation of the SIP PLCP group (either DS1 or DS3 subgroup) is mandatory if the PLCP is implemented. Either sipDS1PLCPTable or sipDS3PLCPTable must be implemented as appropriate.
Implementation of the SMDS Applications group (ipOverSMDS) is mandatory for systems that implement the IP-over-SMDS Interface Protocol, as required by RFC 1209.
BAsize field validity requires: value not less than 32, not greater than 9220 octets without CRC32, not greater than 9224 octets with CRC32, and must be a multiple of 4 octets. Violations are logged as invalidBAsizeFieldValue errors.
Header Extension structural requirements: Length field must equal 3; element Length must not exceed 12; Version element (Length=3, Type=0, Value=1) must appear first; Carrier Selection element must appear second with Type=1, Length 4/6/8, and valid BCD-encoded CIC. PAD must not be exactly 9 octets.
ipOverSMDSTable maps each IP address to its SMDS addressing: ipOverSMDSHA (individual SMDS address), ipOverSMDSLISGA (group address for the Logical IP Subnetwork), and ipOverSMDSARPReq (SMDS address to which ARP Requests are sent). Indexed by interface and IP address.
MRI Timeout error (type 12) is declared when the elapsed time between receipt of a BOM and its corresponding EOM exceeds the Message Receive Interval for the transport signal format.
sipDS1PLCPTable and sipDS3PLCPTable each provide per-port PLCP counters: SEFSs (Severely Errored Framing Seconds), AlarmState, and UASs (Unavailable Seconds) as defined by TR-TSV-000773.
sipL2BomOrSSMsMIDErrors counts L2PDUs that are SSMs with MID not equal to zero or BOMs with MID equal to zero, both of which are protocol violations.
sipL2EomsMIDErrors counts received EOM L2PDUs for which there is no active receive process for the MID (i.e., an EOM without a corresponding BOM) or where the EOM has MID equal to zero.
sipL2PayloadLengthErrors counts L2PDUs with invalid payload lengths: SSM payloads outside 28–44 octets, BOM or COM payloads not equal to 44 octets, or EOM payloads outside 4–44 octets.
sipL2Table provides per-port L2 error counters: sipL2HcsOrCRCErrors, sipL2PayloadLengthErrors, sipL2SequenceNumberErrors, sipL2MidCurrentlyActiveErrors, sipL2BomOrSSMsMIDErrors, and sipL2EomsMIDErrors. Total L2 errors equal the sum of all six counters.
sipL3InvalidSMDSAddressTypes counts L3PDUs where the Address_Type subfield (four most significant bits of the 64-bit address) is not equal to 1100 or 1110, or where a Source Address has type 1110 (a group address, which is invalid for source).
sipL3PDUErrorTable logs the latest occurrence of 12 syntactic L3PDU error types, indexed by interface and error type. Each entry records the source address, destination address, and a sysUpTime timestamp. When sipL3PDUErrorTimeStamp equals zero, the entry contains no valid information.
sipL3PDUErrorType enumerates 12 error categories: erroredDAFieldFormat (1), erroredSAFieldFormat (2), invalidBAsizeFieldValue (3), invalidHdrExtLength (4), invalidHdrExtElementLength (5), invalidHdrExtVersionElementPositionLenthOrValue (6), invalidHdrExtCarSelectElementPositionLenghtValueOrFormat (7), hePADError (8), beTagMismatch (9), baSizeFieldNotEqualToLengthField (10), incorrectLength (11), mriTimeout (12).
sipL3Table provides per-port counters: sipL3ReceivedIndividualDAs, sipL3ReceivedGAs, sipL3UnrecognizedIndividualDAs, sipL3UnrecognizedGAs, sipL3SentIndividualDAs, sipL3SentGAs, sipL3Errors, sipL3InvalidSMDSAddressTypes, and sipL3VersionSupport.
sipL3VersionSupport is an INTEGER bitmask indicating which SIP versions an interface supports. For each supported version V, 2^(V-1) is added to the sum; version 1 is the least significant bit. A port supporting versions 1 and 2 returns value 3.
Security issues are not discussed in this memo. No authentication, access control, or privacy mechanisms for SNMP access to SIP MIB objects are specified.
sipDS1PLCPAlarmState and sipDS3PLCPAlarmState each define three states: noAlarm (no alarms present), receivedFarEndAlarm (incoming Yellow Signal received), and incomingLOF (loss of frame failure condition declared). Transitions are triggered by physical layer events per TR-TSV-000773.
SMDSAddress is encoded as an OCTET STRING of SIZE 8 (64 bits). The four most significant bits encode the address type: '1100' for individual addresses and '1110' for group addresses. The remaining 60 bits carry the BCD-encoded SMDS address.