Definitions of Managed Objects for HPR using SMIv2
Extracted elements (29)
ARB (Adaptive Rate-Based) flow and congestion control is performed only at the RTP endpoints; intermediate HPR nodes are not involved. This design keeps per-hop complexity low and allows the endpoints to prevent congestion rather than react to it.
The HPR MIB deliberately omits configuration of HPR nodes, protocol-specific uses of HPR (such as APPN), and traps. Traps for Alert conditions affecting HPR resources are instead defined in the APPN MIB, which may reference HPR MIB objects via VariablePointer in the affectedObject.
The number of entries retained in hprRtpStatusTable and how long individual entries are kept is explicitly left as an implementation choice. This allows implementations to balance memory use against the need for trend analysis and problem determination.
hprNodeCpName has the same value as appnNodeCpName in the APPN MIB when both objects refer to the same APPN node. Similarly, appnNodeCounterDisconTime in the APPN MIB is used to detect discontinuities in HPR global counters.
The hprCompliance MODULE-COMPLIANCE declares hprGlobalConfGroup, hprAnrRoutingConfGroup, and hprTransportUserConfGroup as unconditionally MANDATORY-GROUPS for all SNMPv2 entities implementing the HPR MIB.
The hprRtpConfGroup is conditionally mandatory: it is required for HPR implementations that support the HPR Transport Tower. Implementations not supporting the transport tower need not implement this group.
ARB send-rate objects hprRtpMaxSendRate, hprRtpMinSendRate, and hprRtpCurSendRate (hprRtpEntry 16–18) are Gauge32 values in bytes per second. Max and min are high/low-water marks for the entire connection lifetime, not just the current path.
hprAnrCounterState (hprAnrRouting 2) is a read-write INTEGER allowing a management station to turn ANR packet counting on (active(2)) or off (notActive(1)) in the hprAnrRoutingTable. Its initial value is an implementation choice.
hprAnrRoutingTable (hprAnrRouting 4) correlates each incoming ANR label assigned by this node with the outbound TG or local NCE to which packets are forwarded. Each entry carries the label type, destination TG or NCE identity, and a received-packet counter.
hprAnrType (hprAnrRoutingEntry 2) is a read-only INTEGER indicating whether an ANR label identifies a local NCE (nce(1)) or an outbound TG (tg(2)). When nce(1), the hprAnrOutTgDest and hprAnrOutTgNum objects carry no meaning.
hprNceTable (hprTransportUser 1) identifies all Network Connection Endpoints at the node, indexed by hprNceId (OCTET STRING SIZE 1..8). Each entry carries the NCE's function types (HprNceTypes), default NCE function types, and a 4-octet NCE Instance Identifier (NCEII).
HprNceTypes is a TEXTUAL-CONVENTION defined as a BITS type with four values: controlPoint(0), logicalUnit(1), boundaryFunction(2), and routeSetup(3). It identifies the set of functions provided by a Network Connection Endpoint (NCE).
hprNodeCpName (hprGlobal 1) is a read-only SnaControlPointName giving the administratively assigned APPN network name for the HPR node. It has the same value as appnNodeCpName in the APPN MIB when both refer to the same node.
hprOperatorPathSwitchSupport (hprGlobal 2) is a read-only INTEGER with three values: notSupported(1), switchTriggerSupported(2), and switchToPathSupported(3). It indicates the implementation's level of support for operator-requested RTP path switches.
HprRtpCounter is a TEXTUAL-CONVENTION with SYNTAX Counter32 used for RTP connection statistics. Management Stations detect discontinuities by monitoring the correspondingly indexed hprRtpCounterDisconTime object.
hprRtpPathSwitchTrigger (hprRtpEntry 6) is a read-write INTEGER with values ready(1) and switchPathNow(2). Setting it to switchPathNow(2) triggers an immediate operator-requested path switch; repeated sets to switchPathNow each trigger a fresh switch. No specific new path can be specified via this object.
hprRtpRscv (hprRtpEntry 7) is a read-only OCTET STRING of SIZE 0..255 carrying the forward Route Selection Control Vector for the RTP connection. The value returned during an active path switch is implementation-dependent and may be the old path, the new path, or a zero-length string.
hprRtpSmRdTripDelay (hprRtpEntry 19) is a Gauge32 in units of 1/1000ths of a second representing the smoothed round-trip delay for the RTP connection, used by the ARB algorithm for adaptive rate control.
hprRtpStatusCause (hprRtpStatusEntry 11) records the reason for a path switch: other(1), rtpConnFail(2), locLinkFail(3), remLinkFail(4), or operRequest(5). Remote link failures are learned from Topology Database Updates (TDUs).
hprRtpStatusLastAttemptResult (hprRtpStatusEntry 12) records the outcome of the last path switch attempt with eight values including successful(1), directorySearchFailed(3), rscvCalculationFailed(4), negativeRouteSetupReply(5), backoutRouteSetupReply(6), and timeoutDuringFirstAttempt(7).
hprRtpStatusTable (hprRtp 3) records historical information for each completed RTP path switch attempt, indexed by (hprRtpStatusLocNceId, hprRtpStatusLocTcid, hprRtpStatusIndex). Each entry includes start/end timestamps, old and new RSCVs, cause, and last-attempt result.
hprRtpTable (hprRtp 2) contains one entry per RTP connection, indexed by the pair (hprRtpLocNceId, hprRtpLocTcid). Each entry records remote CP name, NCE IDs, TCIDs, state, timers, ARB send rates, round-trip delay, packet/byte counters, and path-switch statistics.
The HPR MIB module is registered at OID { snanauMIB 6 }, where snanauMIB is { mib-2 34 }. This establishes the top-level OID arc for all HPR managed objects.
Read-only objects in the HPR MIB expose network topology, configuration, and performance data. Some enterprises treat this as a sensitive corporate asset and may wish to restrict SNMP access to most MIB objects, even though no passwords or user data are exposed.
The hprRtpPathSwitchTrigger object is the sole read-write object with operational impact: setting it to switchPathNow can trigger path switches that, if done frequently across many RTP connections, can adversely affect overall network performance. SNMP access to this object is recommended to be restricted.
hprRtpState (hprRtpEntry 9) defines six states for an RTP connection: rtpListening (waiting for call-in), rtpCalling (call-out in progress), rtpConnected (active), rtpPathSwitching (path switch timer running), rtpDisconnecting (no sessions; bringing down), and other(99). Transitions reflect connection lifecycle and path-switch events.
hprAnrLabel is an OCTET STRING of SIZE 1..8 that indexes the ANR routing table. Each HPR node assigns unique ANR labels per outbound link; label size is node-defined, and nodes only interpret their own labels.
hprNceInstanceId (hprNceEntry 4) is a fixed 4-octet OCTET STRING. A new, unique NCEII is assigned each time an NCE is activated (IPL'd), allowing management stations to detect NCE restarts.
hprRtpLocTcid and hprRtpRemTcid are both OCTET STRING of fixed SIZE 8, carrying the local and remote Transport Connection Identifiers for an RTP connection. Values can be cross-referenced against appnIsInRtpTcid or appnIsRtpTcid in the APPN MIB.