DECnet Phase IV MIB Extensions
obsoleted by
- rfc-1559 — DECnet Phase IV MIB Extensions
Extracted elements (28)
All enumerated INTEGER values in this MIB are incremented by one relative to their standard DECnet Phase IV (NICE protocol) numeric codes. This offset is required to maintain compliance with RFC 1155, which reserves zero as a valid integer but DECnet uses zero-based enumerations.
Object names and definitions were taken directly from the DIGITAL Network Architecture Network Management Functional Specification Version 4.0.0 (July 1983) and then adapted to be as consistent as possible with RFC 1156 MIB naming conventions. The term EXECUTOR refers exclusively to the local DECnet software node and is not intended to affect any other protocols running on the system.
Two distinct buffer size parameters are defined: phivRouteBuffSize (maximum Routing layer forwarding size) and phivRouteSegBuffSize (maximum end-to-end segment size for End Communication layer). Both include an extra 6 bytes for backward compatibility with Phase III parameter definitions. The segment buffer size must be less than or equal to the buffer size; they may differ to allow rolling buffer size changes across the network without service interruption.
phivCircuitLineIndex is defined to be the same value as IfIndex from the standard Internet MIB, linking DECnet circuit entries to the standard interface table. Similarly phivCountersIndex and phivDDCMPLineCountIndex equal IfIndex for their respective tables.
This MIB is designed to be used in conjunction with RFC 1155 (SMI), RFC 1213 (MIB-II), and RFC 1157 (SNMP) to provide integrated management of combined TCP/IP and DECnet Phase IV networks from a single IP-based management station. The phiv subtree hangs directly off mib-2, making DECnet objects accessible via standard SNMP operations.
Implementation of the Circuit Group is mandatory for all systems. It includes the Circuit Parameters Table (circuit 1) and Circuit Counters Table (circuit 2) indexed by phivCircuitIndex.
Implementation of the Counters Group is mandatory for systems that only support DECnet-style latching counters. phivCountersCountTable provides Ethernet-level counters including multicast bytes/blocks, collision statistics (deferred, single collision, multiple collision), send failure, collision detect failure, receive failure, unrecognized frame destination, data overrun, and buffer unavailability.
Implementation of the DDCMP Circuit Group is mandatory for all systems that support DDCMP circuits. It covers DDCMP circuit parameters, DDCMP circuit counters, and DDCMP line counters.
Implementation of the DDCMP Multipoint Circuit Control Group is mandatory for all systems that support DDCMP multipoint control circuits. It includes global scheduling timers (phivControlSchedTimer, phivControlDeadTimer, phivControlDelayTimer, phivControlStreamTimer) and the per-tributary Control Parameters Table.
Implementation of the End Communication Layer Group is mandatory for all systems that implement end layer communications. It includes the Remote State Table, End System Counter Table, and supplementary scalars such as phivEndMaxLinks and phivEndRetransmitFactor.
Implementation of the Ethernet Group is mandatory for all systems that support Ethernet links. It includes phivEthLinkParametersTable with designated router address, maximum router count, router priority, and hardware address per Ethernet interface.
Implementation of the Routing Layer Group is mandatory for all systems that implement level 1 routing layer communications. Key parameters include phivRouteMaxCost, phivRouteMaxHops, phivRouteMaxVisits, phivRouteBuffSize, and phivRouteSegBuffSize.
Implementation of the Session Layer Group is mandatory for all systems that implement session layer communications. It includes phivSessionSystemName, phivSessionInTimer, and phivSessionOutTimer.
Implementation of the System Group (phivSystem) is mandatory for all systems. It contains phivSystemState and phivExecIdent.
PhivCounter is an INTEGER datatype for DECnet counters that latch at their maximum specified value until the system is restarted or the counters are reset to zero by the user or management software.
phivEndCountTable (end 2) is indexed by phivEndCountHostNodeID and tracks per-destination end-system counters: user bytes/messages sent and received, total bytes/messages, connects received/sent, response timeouts, and received connect resource errors.
phivEndRemoteTable (end 1) is indexed by phivEndRemoteHostNodeID (PhivAddr) and provides per-remote-node state, circuit index, active logical link count, and average round-trip delay in seconds.
phivEthHardwareAddr (ethernet 1.5) is a read-only 6-octet OCTET STRING representing the Ethernet hardware address as seen by the DECnet software. This value is explicitly noted to differ from ifPhysAddress in the standard Internet MIB.
phivLevel1RouteTable (routing 22) is indexed by phivLevel1RouteNodeAddr (PhivAddr) and provides per-destination routing information: circuit index, total path cost, hop count, and next-hop node address.
phivRouteCountVerifReject (routing 21) counts routing verification rejects, and phivRouteCountAgedPktLoss, phivRouteCountNodeUnrPktLoss, phivRouteCountOutRngePktLoss, phivRouteCountOverSzePktLoss, phivRouteCountPacketFmtErr, and phivRouteCountPtlRteUpdtLoss track distinct routing error categories. All are reset together via phivRouteCountZeroCount.
phivRouteType (routing 14) identifies the executor node type as one of: routing-III, nonrouting-III, area, routing-IV, or nonrouting-IV. Nonrouting nodes can send/receive packets but cannot forward transit traffic; area nodes route between areas.
The DECnet Phase IV MIB subtree is rooted at phiv OBJECT IDENTIFIER ::= { mib-2 18 }, with fourteen named groups: phivSystem (1), phivManagement (2), session (3), end (4), routing (5), circuit (6), ddcmp (7), control (8), ethernet (9), counters (10), adjacency (11), line (12), nonBroadcastLine (14), and area (15).
The routing group defines packet-lifetime control via phivRouteMaxVisits (1..63): packets arriving at the executor that are not destined for it and have visited more than this many nodes are discarded. This parameter must not be less than the maximum path length of the network.
Section 7 of the RFC addresses security considerations. Several objects in this MIB have read-write access (including phivSystemState, phivEndRemoteState, and circuit parameters), meaning unauthorized SNMP write access could alter the operational state of DECnet nodes and circuits. Implementers should apply the community-based access controls provided by SNMPv1 (RFC 1157) to restrict write access.
phivCircuitCommonState defines four circuit states: ON (1), OFF (2), SERVICE (3), and CLEARED (4). phivCircuitCommonSubState provides thirteen operational substates including starting, reflecting, looping, loading, dumping, triggering, autoservice, autoloading, autodumping, autotriggering, synchronizing, failed, and running.
phivSystemState defines four executor node states: ON (allows logical links), OFF (no new links, terminates existing links, stops routing), SHUT (no new links, preserves existing until gone, then transitions to OFF), and RESTRICTED (no new incoming logical links from other nodes). The same state model applies to phivEndRemoteState for remote nodes.
The DDCMP multipoint tributary polling state machine (phivControlPollingState) has five states: AUTOMATIC, ACTIVE, INACTIVE, DYING, and DEAD. When in AUTOMATIC mode, phivControlPollingSubState shows the algorithm-determined substate; thresholds phivControlDeadThreshold, phivControlDyingThreshold, and phivControlInactThreshold control transitions between states.
PhivAddr is a 2-octet OCTET STRING encoding a DECnet Phase IV node address. The most significant 6 bits of the first octet hold the area number; the next 2 bits of the first octet plus the entire second octet hold the host address.