The Virtual Fabrics MIB
Extracted elements (22)
RFC 4044 was defined before Virtual Switches existed and applied only to physical switches, so its tables were not read-create. This MIB introduces read-create tables (t11vfVirtualSwitchTable with RowStatus) to allow administrators to create Virtual Switches remotely via SNMP.
StorageType objects are included in all tables of this MIB, and the document notes that the StorageTypes used here should also apply to the RFC 4044 tables this MIB augments, compensating for the absence of StorageType definitions in the original RFC 4044.
Virtual Fabrics are designed to achieve better utilization of physical infrastructure and to isolate events in one Virtual Fabric from affecting other Fabrics, allowing each to be managed independently like a traditional Fabric.
In switches that do not support Virtual Fabrics, t11vfCoreSwitchMaxSupported has the value 1. This allows the MIB to be used uniformly across both VF-capable and non-VF switches.
This MIB extends RFC 4044 (FC-MGMT-MIB) by augmenting fcmSwitchTable and fcmPortEntry. The t11vfVirtualSwitchTable and t11vfPortTable use AUGMENTS clauses, so creating or deleting a row in t11vfVirtualSwitchTable simultaneously creates or deletes the corresponding row in fcmSwitchTable.
A Virtual Switch must reside in a single Core Switch. A Core Switch is defined as the set of entities sharing the same Core Switch_Name (WWN).
Deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. It is RECOMMENDED to deploy SNMPv3 with cryptographic security (authentication and privacy) enabled.
Implementers are RECOMMENDED to consider the SNMPv3 security features (RFC 3410 section 8), including full support for SNMPv3 cryptographic mechanisms for authentication and privacy.
The compliance statement (t11vfMIBCompliance) makes the single group t11vfGeneralGroup mandatory. For all writable objects, write access is not required for compliance — MIN-ACCESS read-only is permitted for all read-write and read-create objects.
When a row in t11vfLocallyEnabledTable is in active(1) state, no object in that row can be modified except t11vfLocallyEnabledRowStatus and t11vfLocallyEnabledStorageType.
t11vfCoreSwitchTable contains one entry per Core Switch, indexed by fcmInstanceIndex and t11vfCoreSwitchSwitchName (an 8- or 16-byte WWN). It exposes the maximum number of supported Virtual Fabrics (t11vfCoreSwitchMaxSupported, range 1..4095) and a StorageType.
t11vfLocallyEnabledTable tracks which VF_IDs are locally enabled on each port, indexed by InterfaceIndex and T11FabricIndex. The set of VFs actually operational on a port is the bitwise AND of locally-enabled VF_IDs on both sides of the link.
t11vfPortTable augments fcmPortEntry with four Virtual Fabric attributes per physical port: Port VF_ID (default VF for untagged frames), tagging administrative status (off/on/auto), tagging operational status (off/on), and StorageType.
t11vfPortTaggingAdminStatus configures VF tagging per port with three values: off(1) disables tagging, on(2) enables it if the attached port does not prohibit it, auto(3) enables it if the peer requests it.
t11vfVirtualSwitchTable augments fcmSwitchTable (from RFC 4044) with Virtual Switch-specific columns: VF_ID (t11vfVirtualSwitchVfId), Core Switch WWN (t11vfVirtualSwitchCoreSwitchName), RowStatus, and StorageType. It supports remote creation of Virtual Switches via SNMP.
The Control VF_ID is implicitly enabled on all ports and virtual switches and cannot be set via MIB objects. Communication with the Control VF_ID is required, per FC-SW-4 section 12.1 and 12.2.
The T11-FC-VIRTUAL-FABRIC-MIB module (OID mib-2 147) defines managed objects for Fibre Channel Virtual Fabrics, comprising four main tables: t11vfCoreSwitchTable, t11vfVirtualSwitchTable, t11vfPortTable, and t11vfLocallyEnabledTable.
IANA assigned OID 147 under the mib-2 subtree for the T11-FC-VIRTUAL-FABRIC-MIB module (t11FcVirtualFabricMIB OBJECT IDENTIFIER ::= { mib-2 147 }).
Read-only objects such as t11vfVirtualSwitchCoreSwitchName, t11vfPortTaggingOperStatus, and t11vfLocallyEnabledOperStatus can reveal Virtual Fabric topology; GET and NOTIFY access should be controlled and values encrypted in transit where sensitive.
Read-write and read-create objects (t11vfCoreSwitchMaxSupported, t11vfVirtualSwitchVfId, t11vfPortTaggingAdminStatus, t11vfPortVfId, t11vfLocallyEnabledRowStatus, and related StorageType/RowStatus objects) are sensitive because they allow remote reconfiguration of Virtual Fabrics on switches and ports; SET operations in non-secure environments can negatively affect network operations.
Each Virtual Fabric is identified by a 12-bit Virtual Fabric ID (VF_ID). Frames from multiple Virtual Fabrics share a physical link via a Virtual Fabric Tagging Header (VFT_Header) that carries the VF_ID to identify the frame's Virtual Fabric membership.
t11vfCoreSwitchSwitchName and t11vfVirtualSwitchCoreSwitchName are typed as FcNameIdOrZero with SIZE(8 | 16), representing an 8-byte or 16-byte World Wide Name (WWN) identifying the Core Switch.