Traffic Engineering Link Management Information Base
Extracted elements (26)
Bandwidth values use a 4-octet IEEE 754 single-precision floating-point encoding (TeLinkBandwidth) not for fractional precision but to allow specification of very large bandwidth numbers that cannot be expressed with 32-bit integers. This matches the encoding used in OSPF GMPLS extensions.
The TE link abstraction is introduced to aggregate link properties for use by OSPF, GMPLS, and LMP, reducing the volume of routing information exchanged in the network and thereby improving routing scalability. The bundled link extends this abstraction to group multiple TE links under a single management entity.
The teLinkDescriptorTable entries are derived from componentLinkDescriptorTable entries, and teLinkBandwidthTable values are aggregations of componentLinkBandwidthTable values. This layered derivation model allows TE link properties to be automatically consistent with their constituent component links.
For unnumbered TE links, teLinkAddressType is set to unknown(0), teLinkLocalIpAddr and teLinkRemoteIpAddr are zero-length strings, and the teLinkOutgoingIfId/teLinkIncomingIfId objects carry the unnumbered interface identifiers. For numbered links, InetAddress size is 4 (IPv4) or 16 (IPv6) octets.
If the TE link is a Forwarding Adjacency (FA), teLinkLocalIpAddr is set to the head-end address and teLinkRemoteIpAddr to the tail-end address of the FA-LSP. If ipAddrTable is implemented, teLinkLocalIpAddr must match the corresponding ipAdEntAddr value for the same ifIndex.
TE link interfaces are logical interfaces with no media-level addresses; therefore, the ifRcvAddressTable is not applicable to these interfaces and need not be implemented.
TE Link interfaces are represented in the ifTable with ifType value 200, as allocated by IANAifType. The ifStackTable is used to represent hierarchical relationships between MPLS interfaces, bundled links, TE links, and component links, with higher-layer interfaces referencing lower-layer ones.
Traffic counters (ifInOctets, ifOutOctets, ifInErrors, ifInUnknownProtos, ifOutErrors, ifHCInOctets, ifHCOutOctets) on a TE link are cumulative across all subinterfaces it binds. Support for these counters is not required if the encoding type is clear-channel.
An ifEntry with ifType teLink(200) MUST exist in the ifTable before a teLinkEntry can be created with the corresponding ifIndex. If the ifEntry is destroyed, the corresponding teLinkEntry and all associated entries in teLinkDescriptorTable, teLinkSrlgTable, and teLinkBandwidthTable are also destroyed.
Component links that belong to the same TE link MUST be compatible. If the componentLinkTable and teLinkDescriptorTable are managed independently, mechanisms SHOULD be put in place to ensure consistency between the two tables.
For all RowStatus objects in this MIB, support for notReady(3) and createAndWait(5) states is not required. Only active(1), notInService(2), createAndGo(4), and destroy(6) need to be supported.
No writable (read-create) object in any row of the MIB tables (teLinkTable, teLinkDescriptorTable, teLinkSrlgTable, teLinkBandwidthTable, componentLinkTable, componentLinkDescriptorTable, componentLinkBandwidthTable) can be modified when the row's RowStatus object is in the active(1) state.
TE links that form a bundled link MUST have compatible traffic engineering parameters: the same resource class, link metric, and protection type. All component links within a TE link must also share the same traffic engineering metric.
The teLinkSrlgGroup is mandatory for GMPLS-enabled devices in both full-compliance and read-only-compliance conformance statements. The teLinkPscGroup is mandatory for devices supporting packet switching capability, and teLinkTdmGroup is mandatory for devices supporting TDM switching capability.
TeLinkEncodingType defines link encoding values from GMPLS signaling: packet (1), ethernet (2), ansiEtsiPdh (3), sdhItuSonetAnsi (5), digitalWrapper (7), lambda (8), fiber (9), and fiberChannel (11). Values are non-contiguous per RFC 3471.
TeLinkSwitchingCapability defines the interface switching capability values drawn from OSPF GMPLS extensions: packetSwitch1–4 (1–4), layer2Switch (51), tdm (100), lambdaSwitch (150), and fiberSwitch (200). Values are non-contiguous per the referenced GMPLS specification.
The componentLinkDescriptorTable (teLinkObjects 6) and componentLinkBandwidthTable (teLinkObjects 7) mirror the TE link descriptor and bandwidth tables at the component link level. TE link descriptor and bandwidth values (max reservable bandwidth, min/max LSP bandwidth, unreserved bandwidth) are derived as aggregates from the corresponding component link tables.
The componentLinkTable (teLinkObjects 5) enumerates component links with their maximum reservable bandwidth, preferred protection role (primary/secondary), and current protection status. Any ifEntry interface type defined for TE link interworking (ATM, Frame Relay, Ethernet, etc.) may serve as a component link.
The teLinkBandwidthTable (teLinkObjects 4) provides priority-based unreserved bandwidth per TE link, indexed by ifIndex and teLinkBandwidthPriority (0–7). The unreserved bandwidth at priority p is the sum of unreserved bandwidths at priority p across all component links associated with the TE link, excluding protecting-only links.
The teLinkDescriptorTable (teLinkObjects 2) holds interface switching capability descriptors for TE links, indexed by ifIndex and teLinkDescriptorId. Each descriptor specifies switching capability, encoding type, minimum LSP bandwidth, maximum LSP bandwidth at each of 8 priorities (0–7), MTU, and SONET/SDH indication.
The teLinkSrlgTable (teLinkObjects 3) stores Shared Risk Link Groups associated with TE links, indexed by ifIndex and teLinkSrlg. An SRLG is a 32-bit number unique within an IGP domain; zero is a valid SRLG value. Destroying a TE link's ifEntry also destroys all associated SRLG entries.
The teLinkTable (teLinkObjects 1) represents TE links including bundled links, indexed by ifIndex. Each entry requires a corresponding ifEntry with ifType teLink(200); destroying the ifEntry also destroys the teLinkEntry. Key fields include address type, local/remote IP, metric, protection type, working priority, resource class, and incoming/outgoing interface identifiers.
The TE-LINK-STD-MIB module is assigned the OID { transmission 200 }, registering the teLinkStdMIB module-identity under the SNMP transmission subtree. This is the sole IANA consideration; no new registries are created.
The MIB module contains writable objects that could be used to configure or disrupt TE link settings. Unauthorized modifications could affect traffic engineering parameters and disrupt network operation. Implementations should use SNMPv3 with authentication and privacy to protect against unauthorized access and modification.
TeLinkBandwidth is a 4-octet IEEE 754 single-precision floating-point value representing link bandwidth in bits per second. The floating-point format is used not for fractional precision but to allow representation of large bandwidth values that exceed the range of 32-bit integers.
TeLinkPriority is an Unsigned32 in the range 0..7, where 0 is the highest priority and 7 is the lowest. This priority is used for bandwidth accounting on TE and component links, resource allocation, and rerouting purposes.