Multiprotocol Label Switching (MPLS) Label-Controlled Asynchronous Transfer Mode (ATM) and Frame-Relay Management Interface Definition
Extracted elements (23)
Although RFC 3057 implies multiple VPs may be used for indirect LC-ATM connections, in practice only a single VP is used; therefore mplsLcAtmLcAtmVPI models only a single VPI value rather than a range or list.
The label partition model restricts control and unlabeled VPI/VCI to single values each, which is more restrictive than RFC 3035 allows. This reflects widespread implementation practice and was deemed sufficiently flexible by the MPLS working group for operational needs.
The LC-FR MIB does not support mixed labeled and unlabeled traffic even though RFC 3034 calls for it, because this capability is not used operationally. The authors deliberately omitted it to match real-world deployment.
When LDP is used to distribute labels for LC-ATM interfaces, label configuration information may also be available in MPLS-LDP-ATM-STD-MIB (RFC 3815); for LC-FR interfaces, in MPLS-LDP-FRAME-RELAY-STD-MIB (RFC 3815). These MIBs complement the interface configuration tables defined here.
For indirectly connected LC-ATM interfaces, the label MUST be encoded entirely within the VCI field because the VPI field is not available to MPLS on such interfaces.
For writable implementations of mplsLcAtmStdInterfaceConfTable, an agent MUST NOT allow modification to objects once RowStatus is set to active(1), except to mplsLcAtmStdIfConfRowStatus and mplsLcAtmStdIfConfStorageType.
For writable implementations of mplsLcFrStdInterfaceConfTable, an agent MUST NOT allow modification to objects once RowStatus is set to active(1), except to mplsLcFrStdInterfaceConfRowStatus and mplsLcFrStdInterfaceConfStorageType.
mplsLcAtmStdUnlabTrafVci and mplsLcAtmStdCtrlVci MUST NOT be equal; similarly, mplsLcAtmStdCtrlVpi and mplsLcAtmStdUnlabTrafVpi MUST NOT be equal. This ensures distinct channels for control and unlabeled traffic.
The DLCI ranges represented by mplsLcFrStdTrafficMinDlci to mplsLcFrStdTrafficMaxDlci and mplsLcFrStdCtrlMinDlci to mplsLcFrStdCtrlMaxDlci MUST NOT overlap, ensuring traffic and control DLCI ranges are distinct.
When configuring entries in mplsLcAtmStdInterfaceConfTable, the corresponding ifEntry and mplsInterfaceConfEntry MUST exist beforehand. If a manager attempts to create an entry for an mplsInterfaceConfEntry that does not support LC-ATM, the agent MUST return an inconsistentValue error.
When configuring entries in mplsLcFrStdInterfaceConfTable, the corresponding ifEntry and mplsInterfaceConfEntry MUST exist beforehand. If a manager attempts to create an entry for an mplsInterfaceConfEntry that does not support LC-FR, the agent MUST return an inconsistentValue error.
mplsLcAtmLcAtmVPI specifies the VPI value used for indirectly connected LC-ATM interfaces. For indirect connections the VPI field is not available to MPLS, so the label MUST be encoded entirely within the VCI field per RFC 3035. Default is 0 (used for directly connected interfaces).
mplsLcAtmStdCtrlVpi and mplsLcAtmStdCtrlVci define the VPI and VCI values over which the LSR accepts LDP control traffic on an LC-ATM interface. These are read-create objects of type AtmVpIdentifier and MplsAtmVcIdentifier respectively.
mplsLcAtmStdUnlabTrafVpi and mplsLcAtmStdUnlabTrafVci define the VPI and VCI values over which the LSR accepts unlabeled traffic on an LC-ATM interface. These are read-create objects of type AtmVpIdentifier and MplsAtmVcIdentifier respectively.
mplsLcAtmStdVcMerge is a TruthValue object indicating whether an LC-ATM interface supports ATM VC merge. Default is false(2); if true(1) the interface supports merging multiple VCs into one.
mplsLcAtmVcDirectlyConnected is a TruthValue indicating whether an LC-ATM interface is directly or indirectly (via a VP) connected. Default is true(1) for direct connection; false(2) means VP-based indirect connection.
The LC-FR interface configuration table (mplsLcFrStdInterfaceConfTable) contains four DLCI range objects: mplsLcFrStdTrafficMinDlci, mplsLcFrStdTrafficMaxDlci (traffic DLCI range) and mplsLcFrStdCtrlMinDlci, mplsLcFrStdCtrlMaxDlci (control DLCI range), all of type DLCI.
The mplsLcAtmStdInterfaceConfTable sparsely extends the MPLS-LSR-STD-MIB's mplsInterfaceConfTable to identify MPLS interfaces that have LC-ATM capability. Each entry is indexed by mplsInterfaceIndex and exists only when corresponding ifTable and mplsInterfaceConfTable entries exist.
The mplsLcFrStdInterfaceConfTable sparsely extends the MPLS-LSR-STD-MIB's mplsInterfaceConfTable to identify MPLS interfaces that have LC-Frame Relay capability. Each entry is indexed by mplsInterfaceIndex and exists only when corresponding ifTable and mplsInterfaceConfTable entries exist.
IANA assigned { mplsStdMIB 10 } to the MPLS-LC-FR-STD-MIB module defined in this document. New assignments under mplsStdMIB can only be made via Standards Action.
IANA assigned { mplsStdMIB 9 } to the MPLS-LC-ATM-STD-MIB module defined in this document. New assignments under mplsStdMIB can only be made via Standards Action.
Deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED; SNMPv3 with cryptographic security (authentication and privacy) is RECOMMENDED. Read access to LC-ATM/LC-FR configuration objects may reveal sensitive topology information and should be controlled.
Unauthorized SET access to MplsLcAtmStdInterfaceConfTable and mplsLcFrStdInterfaceConfTable objects could disrupt established traffic on LC-ATM or LC-FR interfaces. SNMPv3 VACM and USM MUST be used with any v3 agent implementing these MIB modules.