All MIBs › RFC1286-MIB
Category: IETF Standards
Description:
Defines bridge management objects for dot1d spanning tree and forwarding tables per RFC 1286.
Imported Objects
What Is RFC1286-MIB?
RFC1286-MIB, formally published as the RFC1286-MIB RFC, is an early IETF standards-track module, part of the classic bridge-MIB lineage, that defines management objects for transparent (Ethernet/Token Ring) bridges implementing the IEEE 802.1D spanning tree algorithm. It exposes bridge-level topology and forwarding-plane data: the bridge's identity and base parameters, spanning tree protocol state (root bridge selection, port roles and states), and the address forwarding/filtering database that maps learned MAC addresses to ports. In monitoring terms it is used to check the hardware/software health of a bridge's Layer 2 forwarding function — whether spanning tree has converged to a stable topology, whether a given port is forwarding, blocking, listening, or disabled, and whether the forwarding table is growing or churning abnormally, which can reveal network loops, flapping links, or misconfigured redundant paths. This module has no dependency beyond the base SMIv1 framework and the IEEE 802.1D bridging standard it models, and it was later formally superseded by RFC 1493's BRIDGE-MIB. It is typically found on legacy Ethernet/Token Ring bridges and early Layer 2 switches used for basic topology and forwarding-table visibility.
IPNetwork Monitor allows you to monitor SNMP objects defined in RFC1286-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.
What Can Be Monitored
- spanning tree port state (forwarding/blocking/disabled)
- root bridge identification
- bridge forwarding/filtering table size
- bridge port learning behavior
Supported Devices
- vendor-neutral, standards-based MIB, not tied to a specific manufacturer
- Ethernet/Token Ring transparent bridges
- early Layer 2 switches
Monitoring Examples
No sample objects were captured for this module in this batch, so specifics beyond the RFC's well-known dot1dBase, dot1dStp, and dot1dTp object groups cannot be confirmed here; conceptually, though, an administrator would poll spanning tree port state to confirm a port is forwarding rather than stuck blocking, and would watch forwarding database size for signs of a MAC address flooding or loop condition. Given the lack of confirmed object names in this batch, this description stays at the conceptual level rather than citing specific OIDs.
OIDs
| OID symbolic | OID numeric | Type | Access | Description |
|---|---|---|---|---|
| dot1dBridge | 1.3.6.1.2.1.17 | |||
| NTF newRoot | 1.3.6.1.2.1.17.0.1 | The newRoot trap indicates that the sending agent has become the new root of the Spanning Tree; the trap is sent by a bridge soon after its election as the new root, e.g., upon expiration of the Topology Change Timer immediately subsequent to its election. | ||
| NTF topologyChange | 1.3.6.1.2.1.17.0.2 | A topologyChange trap is sent by a bridge when any of its configured ports transitions from the Learning state to the Forwarding state, or from the Forwarding state to the Blocking state. The trap is not sent if a newRoot trap is sent for the same transition. | ||
| dot1dBase | 1.3.6.1.2.1.17.1 | |||
| MAC dot1dBaseBridgeAddress | 1.3.6.1.2.1.17.1.1 | MacAddress | read-only | The MAC address used by this bridge when it must be referred to in a unique fashion. It is recommended that this be the numerically smallest MAC address of all ports that belong to this bridge. However it is only required to be unique. When concatenated with dot1dStpPriority a unique BridgeIdentifier is formed which is used in the Spanning Tree Protocol. |
| INT dot1dBaseNumPorts | 1.3.6.1.2.1.17.1.2 | INTEGER | read-only | The number of ports controlled by this bridging entity. |
| INT dot1dBaseType | 1.3.6.1.2.1.17.1.3 | INTEGER | read-only | Indicates what type of bridging this bridge can perform. If a bridge is actually performing a certain type of bridging this will be indicated by entries in the port table for the given type. |
| dot1dBasePortTable | 1.3.6.1.2.1.17.1.4 | not-accessible | A table that contains generic information about every port that is associated with this bridge. Transparent, source-route, and srt ports are included. | |
| dot1dBasePortEntry | 1.3.6.1.2.1.17.1.4.1 | not-accessible | A list of information for each port of the bridge. | |
| INT dot1dBasePort | 1.3.6.1.2.1.17.1.4.1.1 | INTEGER | read-only | The port number of the port for which this entry contains bridge management information. |
| INT dot1dBasePortIfIndex | 1.3.6.1.2.1.17.1.4.1.2 | INTEGER | read-only | The value of the instance of the ifIndex object, defined in [4,6], for the interface corresponding to this port. |
| OID dot1dBasePortCircuit | 1.3.6.1.2.1.17.1.4.1.3 | OBJECT IDENTIFIER | read-only | For a port which (potentially) has the same value of dot1dBasePortIfIndex as another port on the same bridge, this object contains the name of an object instance unique to this port. For example, in the case where multiple ports correspond one- to-one with multiple X.25 virtual circuits, this value might identify an (e.g., the first) object instance associated with the X.25 virtual circuit corresponding to this port. For a port which has a unique value of dot1dBasePortIfIndex, this object can have the value { 0 0 }. |
| CTR dot1dBasePortDelayExceededDiscards | 1.3.6.1.2.1.17.1.4.1.4 | Counter | read-only | The number of frames discarded by this port due to excessive transit delay through the bridge. It is incremented by both transparent and source route bridges. |
| CTR dot1dBasePortMtuExceededDiscards | 1.3.6.1.2.1.17.1.4.1.5 | Counter | read-only | The number of frames discarded by this port due to an excessive size. It is incremented by both transparent and source route bridges. |
| dot1dStp | 1.3.6.1.2.1.17.2 | |||
| INT dot1dStpProtocolSpecification | 1.3.6.1.2.1.17.2.1 | INTEGER | read-only | An indication of what version of the Spanning Tree Protocol is being run. The value 'decLb100(2)' indicates the DEC LANbridge 100 Spanning Tree protocol. IEEE 802.1d implementations will return 'ieee8021d(3)'. If future versions of the IEEE Spanning Tree Protocol are released that are incompatible with the current version a new value will be defined. |
| INT dot1dStpPriority | 1.3.6.1.2.1.17.2.2 | INTEGER | read-write | The value of the write-able portion of the Bridge ID, i.e., the first two octets of the (8 octet long) Bridge ID. The other (last) 6 octets of the Bridge ID are given by the value of dot1dBaseBridgeAddress. |
| TIK dot1dStpTimeSinceTopologyChange | 1.3.6.1.2.1.17.2.3 | TimeTicks | read-only | The time (in hundredths of a second) since the last time a topology change was detected by the bridge entity. |
| CTR dot1dStpTopChanges | 1.3.6.1.2.1.17.2.4 | Counter | read-only | The total number of topology changes detected by this bridge since the management entity was last reset or initialized. |
| BRI dot1dStpDesignatedRoot | 1.3.6.1.2.1.17.2.5 | BridgeId | read-only | The bridge identifier of the root of the spanning tree as determined by the Spanning Tree Protocol as executed by this node. This value is used as the Root Identifier parameter in all Configuration Bridge PDUs originated by this node. |
| INT dot1dStpRootCost | 1.3.6.1.2.1.17.2.6 | INTEGER | read-only | The cost of the path to the root as seen from this bridge. |
| INT dot1dStpRootPort | 1.3.6.1.2.1.17.2.7 | INTEGER | read-only | The port number of the port which offers the lowest cost path from this bridge to the root bridge. |
| TIM dot1dStpMaxAge | 1.3.6.1.2.1.17.2.8 | Timeout | read-only | The maximum age of Spanning Tree Protocol information learned from the network on any port before it is discarded, in units of hundredths of a second. This is the actual value that this bridge is currently using. |
| TIM dot1dStpHelloTime | 1.3.6.1.2.1.17.2.9 | Timeout | read-only | The amount of time between the transmission of Configuration bridge PDUs by this node on any port when it is the root of the spanning tree or trying to become so, in units of hundredths of a second. This is the actual value that this bridge is currently using. |
| INT dot1dStpHoldTime | 1.3.6.1.2.1.17.2.10 | INTEGER | read-only | This time value determines the interval length during which no more than two Configuration bridge PDUs shall be transmitted by this node, in units of hundredths of a second. |
| TIM dot1dStpForwardDelay | 1.3.6.1.2.1.17.2.11 | Timeout | read-only | This time value, measured in units of hundredths of a second, controls how fast a port changes its spanning state when moving towards the Forwarding state. The value determines how long the port stays in a particular state before moving to the next state. For example, how long a port stays in the Listening state when moving from Blocking to Learning. This value is also used, when a topology change has been detected and is underway, to age all dynamic entries in the Forwarding Database. [Note that this value is the one that this bridge is currently using, in contrast to dot1dStpBridgeForwardDelay which is the value that this bridge and all others would start using if/when this bridge were to become the root.] |
| TIM dot1dStpBridgeMaxAge | 1.3.6.1.2.1.17.2.12 | Timeout | read-write | The value that all bridges use for MaxAge when this bridge is acting as the root. Note that 802.1d/D9 specifies that the range for this parameter is related to the value of dot1dStpBridgeHelloTime. The granularity of this timer is specified by 802.1d/D9 to be 1 second. An agent may return a badValue error if a set is attempted to a value which is not a whole number of seconds. |
| TIM dot1dStpBridgeHelloTime | 1.3.6.1.2.1.17.2.13 | Timeout | read-write | The value that all bridges use for HelloTime when this bridge is acting as the root. The granularity of this timer is specified by 802.1d/D9 to be 1 second. An agent may return a badValue error if a set is attempted to a value which is not a whole number of seconds. |
| TIM dot1dStpBridgeForwardDelay | 1.3.6.1.2.1.17.2.14 | Timeout | read-write | The value that all bridges use for ForwardDelay when this bridge is acting as the root. Note that 802.1d/D9 specifies that the range for this parameter is related to the value of dot1dStpBridgeMaxAge. The granularity of this timer is specified by 802.1d/D9 to be 1 second. An agent may return a badValue error if a set is attempted to a value which is not a whole number of seconds. |
| dot1dStpPortTable | 1.3.6.1.2.1.17.2.15 | not-accessible | A table that contains port-specific information for the Spanning Tree Protocol. | |
| dot1dStpPortEntry | 1.3.6.1.2.1.17.2.15.1 | not-accessible | A list of information maintained by every port about the Spanning Tree Protocol state for that port. | |
| INT dot1dStpPort | 1.3.6.1.2.1.17.2.15.1.1 | INTEGER | read-only | The port number of the port for which this entry contains Spanning Tree Protocol management information. |
| INT dot1dStpPortPriority | 1.3.6.1.2.1.17.2.15.1.2 | INTEGER | read-write | The value of the priority field which is contained in the first (in network byte order) octet of the (2 octet long) Port ID. The other octet of the Port ID is given by the value of dot1dStpPort. |
| INT dot1dStpPortState | 1.3.6.1.2.1.17.2.15.1.3 | INTEGER | read-only | The port's current state as defined by application of the Spanning Tree Protocol. This state controls what action a port takes on reception of a frame. If the bridge has detected a port that is malfunctioning it will place that port into the broken(6) state. For ports which are disabled (see dot1dStpPortEnable), this object will have a value of disabled(1). |
| INT dot1dStpPortEnable | 1.3.6.1.2.1.17.2.15.1.4 | INTEGER | read-write | The enabled/disabled status of the port. |
| INT dot1dStpPortPathCost | 1.3.6.1.2.1.17.2.15.1.5 | INTEGER | read-write | The contribution of this port to the path cost of paths towards the spanning tree root which include this port. |
| BRI dot1dStpPortDesignatedRoot | 1.3.6.1.2.1.17.2.15.1.6 | BridgeId | read-only | The unique Bridge Identifier of the Bridge recorded as the Root in the Configuration BPDUs transmitted by the Designated Bridge for the segment to which the port is attached. |
| INT dot1dStpPortDesignatedCost | 1.3.6.1.2.1.17.2.15.1.7 | INTEGER | read-only | The path cost of the Designated Port of the segment connected to this port. This value is compared to the Root Path Cost field in received bridge PDUs. |
| BRI dot1dStpPortDesignatedBridge | 1.3.6.1.2.1.17.2.15.1.8 | BridgeId | read-only | The Bridge Identifier of the bridge which this port considers to be the Designated Bridge for this port's segment. |
| OCT dot1dStpPortDesignatedPort | 1.3.6.1.2.1.17.2.15.1.9 | OCTET STRING | read-only | The Port Identifier of the port on the Designated Bridge for this port's segment. |
| CTR dot1dStpPortForwardTransitions | 1.3.6.1.2.1.17.2.15.1.10 | Counter | read-only | The number of times this port has transitioned from the Learning state to the Forwarding state. |
| dot1dSr | 1.3.6.1.2.1.17.3 | |||
| dot1dSrPortTable | 1.3.6.1.2.1.17.3.1 | not-accessible | A table that contains information about every port that is associated with this source route bridge. | |
| dot1dSrPortEntry | 1.3.6.1.2.1.17.3.1.1 | not-accessible | A list of information for each port of a source route bridge. | |
| INT dot1dSrPort | 1.3.6.1.2.1.17.3.1.1.1 | INTEGER | read-only | The port number of the port for which this entry contains Source Route management information. |
| INT dot1dSrPortHopCount | 1.3.6.1.2.1.17.3.1.1.2 | INTEGER | read-write | The maximum number of routing descriptors allowed in an All Paths or Spanning Tree Explorer frames. |
| INT dot1dSrPortLocalSegment | 1.3.6.1.2.1.17.3.1.1.3 | INTEGER | read-write | The segment number that uniquely identifies the segment to which this port is connected. Current source routing protocols limit this value to the range: 0 through 4095. A value of 65535 signifies that no segment number is assigned to this port. |
| INT dot1dSrPortBridgeNum | 1.3.6.1.2.1.17.3.1.1.4 | INTEGER | read-write | A bridge number uniquely identifies a bridge when more than one bridge is used to span the same two segments. Current source routing protocols limit this value to the range: 0 through 15. A value of 65535 signifies that no bridge number is assigned to this bridge. |
| INT dot1dSrPortTargetSegment | 1.3.6.1.2.1.17.3.1.1.5 | INTEGER | read-write | The segment number that corresponds to the target segment this port is considered to be connected to by the bridge. Current source routing protocols limit this value to the range: 0 through 4095. A value of 65535 signifies that no target segment is assigned to this port. |
| INT dot1dSrPortLargestFrame | 1.3.6.1.2.1.17.3.1.1.6 | INTEGER | read-write | The maximum size of the INFO field (LLC and above) that this port can send/receive. It does not include any MAC level (framing) octets. The value of this object is used by this bridge to determine whether a modification of the LargestFrame (LF, see [14]) field of the Routing Control field of the Routing Information Field is necessary. Valid values as defined by the 802.5 source routing bridging specification[14] are 516, 1500, 2052, 4472, 8144, 11407, 17800, and 65535 octets. Behavior of the port when an illegal value is written is implementation specific. It is recommended that a reasonable legal value be chosen. |
| INT dot1dSrPortSTESpanMode | 1.3.6.1.2.1.17.3.1.1.7 | INTEGER | read-write | Determines how this port behaves when presented with a Spanning Tree Explorer frame. The value 'disabled(2)' indicates that the port will not accept or send Spanning Tree Explorer packets; any STE packets received will be silently discarded. The value 'forced(3)' indicates the port will always accept and propagate Spanning Tree Explorer frames. This allows a manually configured Spanning Tree for this class of packet to be configured. Note that unlike transparent bridging this is not catastrophic to the network if there are loops. The value 'auto-span(1)' can only be returned by a bridge that both implements the Spanning Tree Protocol and has use of the protocol enabled on this port. The behavior of the port for Spanning Tree Explorer frames is determined by the state of dot1dStpPortState. If the port is in the 'forwarding' state, the frame will be accepted or propagated. Otherwise it will be silently discarded. |
| CTR dot1dSrPortSpecInFrames | 1.3.6.1.2.1.17.3.1.1.8 | Counter | read-only | The number of specifically routed frames that have been received from this port's segment. |
| CTR dot1dSrPortSpecOutFrames | 1.3.6.1.2.1.17.3.1.1.9 | Counter | read-only | The number of specifically routed frames that this port has transmitted on its segment. |
| CTR dot1dSrPortApeInFrames | 1.3.6.1.2.1.17.3.1.1.10 | Counter | read-only | The number of all paths explorer frames that have been received by this port from its segment. |
| CTR dot1dSrPortApeOutFrames | 1.3.6.1.2.1.17.3.1.1.11 | Counter | read-only | The number of all paths explorer frames that have been transmitted by this port on its segment. |
| CTR dot1dSrPortSteInFrames | 1.3.6.1.2.1.17.3.1.1.12 | Counter | read-only | The number of spanning tree explorer frames that have been received by this port from its segment. |
| CTR dot1dSrPortSteOutFrames | 1.3.6.1.2.1.17.3.1.1.13 | Counter | read-only | The number of spanning tree explorer frames that have been transmitted by this port on its segment. |
| CTR dot1dSrPortSegmentMismatchDiscards | 1.3.6.1.2.1.17.3.1.1.14 | Counter | read-only | The number of explorer frames that have been discarded by this port because the routing descriptor field contained an invalid adjacent segment value. |
| CTR dot1dSrPortDuplicateSegmentDiscards | 1.3.6.1.2.1.17.3.1.1.15 | Counter | read-only | The number of frames that have been discarded by this port because the routing descriptor field contained a duplicate segment identifier. |
| CTR dot1dSrPortHopCountExceededDiscards | 1.3.6.1.2.1.17.3.1.1.16 | Counter | read-only | The number of explorer frames that have been discarded by this port because the Routing Information Field has exceeded the maximum route descriptor length. |
| dot1dTp | 1.3.6.1.2.1.17.4 | |||
| CTR dot1dTpLearnedEntryDiscards | 1.3.6.1.2.1.17.4.1 | Counter | read-only | The total number of Forwarding Database entries, which have been or would have been learnt, but have been discarded due to a lack of space to store them in the Forwarding Database. If this counter is increasing, it indicates that the Forwarding Database is regularly becoming full (a condition which has unpleasant performance effects on the subnetwork). If this counter has a significant value but is not presently increasing, it indicates that the problem has been occurring but is not persistent. |
| INT dot1dTpAgingTime | 1.3.6.1.2.1.17.4.2 | INTEGER | read-write | The timeout period in seconds for aging out dynamically learned forwarding information. |
| dot1dTpFdbTable | 1.3.6.1.2.1.17.4.3 | not-accessible | A table that contains information about unicast entries for which the bridge has forwarding and/or filtering information. This information is used by the transparent bridging function in determining how to propagate a received frame. | |
| dot1dTpFdbEntry | 1.3.6.1.2.1.17.4.3.1 | not-accessible | Information about a specific unicast MAC address for which the bridge has some forwarding and/or filtering information. | |
| MAC dot1dTpFdbAddress | 1.3.6.1.2.1.17.4.3.1.1 | MacAddress | read-only | A unicast MAC address for which the bridge has forwarding and/or filtering information. |
| INT dot1dTpFdbPort | 1.3.6.1.2.1.17.4.3.1.2 | INTEGER | read-only | Either the value '0', or the port number of the port on which a frame having a source address equal to the value of the corresponding instance of dot1dTpFdbAddress has been seen. A value of '0' indicates that the port number has not been learned but that the bridge does have some forwarding/filtering information about this address (e.g. in the dot1dStaticTable). Implementors are encouraged to assign the port value to this object whenever it is learned even for addresses for which the corresponding value of dot1dTpFdbStatus is not learned(3). |
| INT dot1dTpFdbStatus | 1.3.6.1.2.1.17.4.3.1.3 | INTEGER | read-only | The status of this entry. The meanings of the values are: other(1) : none of the following. This would include the case where some other MIB object (not the corresponding instance of dot1dTpFdbPort, nor an entry in the dot1dStaticTable) is being used to determine if and how frames addressed to the value of the corresponding instance of dot1dTpFdbAddress are being forwarded. invalid(2) : this entry is not longer valid (e.g., it was learned but has since aged-out), but has not yet been flushed from the table. learned(3) : the value of the corresponding instance of dot1dTpFdbPort was learned, and is being used. self(4) : the value of the corresponding instance of dot1dTpFdbAddress represents one of the bridge's addresses. The corresponding instance of dot1dTpFdbPort indicates which of the bridge's ports has this address. mgmt(5) : the value of the corresponding instance of dot1dTpFdbAddress is also the value of an existing instance of dot1dStaticAddress. |
| dot1dTpPortTable | 1.3.6.1.2.1.17.4.4 | not-accessible | A table that contains information about every port that is associated with this transparent bridge. | |
| dot1dTpPortEntry | 1.3.6.1.2.1.17.4.4.1 | not-accessible | A list of information for each port of a transparent bridge. | |
| INT dot1dTpPort | 1.3.6.1.2.1.17.4.4.1.1 | INTEGER | read-only | The port number of the port for which this entry contains Transparent bridging management information. |
| INT dot1dTpPortMaxInfo | 1.3.6.1.2.1.17.4.4.1.2 | INTEGER | read-only | The maximum size of the INFO (non-MAC) field that this port will receive or transmit. |
| CTR dot1dTpPortInFrames | 1.3.6.1.2.1.17.4.4.1.3 | Counter | read-only | The number of frames that have been received by this port from its segment. Note that a frame received on the interface corresponding to this port is only counted by this object if and only if it is for a protocol being processed by the local bridging function. |
| CTR dot1dTpPortOutFrames | 1.3.6.1.2.1.17.4.4.1.4 | Counter | read-only | The number of frames that have been transmitted by this port to its segment. Note that a frame transmitted on the interface corresponding to this port is only counted by this object if and only if it is for a protocol being processed by the local bridging function. |
| CTR dot1dTpPortInDiscards | 1.3.6.1.2.1.17.4.4.1.5 | Counter | read-only | Count of valid frames received which were discarded (i.e., filtered) by the Forwarding Process. |
| dot1dStatic | 1.3.6.1.2.1.17.5 | |||
| dot1dStaticTable | 1.3.6.1.2.1.17.5.1 | not-accessible | A table containing filtering information configured into the bridge by (local or network) management specifying the set of ports to which frames received from specific ports and containing specific destination addresses are allowed to be forwarded. The value of zero in this table as the port number from which frames with a specific destination address are received, is used to specify all ports for which there is no specific entry in this table for that particular destination address. Entries are valid for unicast and for group/broadcast addresses. | |
| dot1dStaticEntry | 1.3.6.1.2.1.17.5.1.1 | not-accessible | Filtering information configured into the bridge by (local or network) management specifying the set of ports to which frames received from a specific port and containing a specific destination address are allowed to be forwarded. | |
| MAC dot1dStaticAddress | 1.3.6.1.2.1.17.5.1.1.1 | MacAddress | read-write | The destination MAC address in a frame to which this entry's filtering information applies. This object can take the value of a unicast address, a group address or the broadcast address. |
| INT dot1dStaticReceivePort | 1.3.6.1.2.1.17.5.1.1.2 | INTEGER | read-write | Either the value '0', or the port number of the port from which a frame must be received in order for this entry's filtering information to apply. A value of zero indicates that this entry applies on all ports of the bridge for which there is no other applicable entry. |
| OCT dot1dStaticAllowedToGoTo | 1.3.6.1.2.1.17.5.1.1.3 | OCTET STRING | read-write | The set of ports to which frames received from a specific port and destined for a specific MAC address, are allowed to be forwarded. Each octet within the value of this object specifies a set of eight ports, with the first octet specifying ports 1 through 8, the second octet specifying ports 9 through 16, etc. Within each octet, the most significant bit represents the lowest numbered port, and the least significant bit represents the highest numbered port. Thus, each port of the bridge is represented by a single bit within the value of this object. If that bit has a value of '1' then that port is included in the set of ports; the port is not included if its bit has a value of '0'. (Note that the setting of the bit corresponding to the port from which a frame is received is irrelevant.) |
| INT dot1dStaticStatus | 1.3.6.1.2.1.17.5.1.1.4 | INTEGER | read-write | This object indicates the status of this entry. other(1) - this entry is currently in use but the conditions under which it will remain so are different from each of the following values. invalid(2) - writing this value to the object removes the corresponding entry. permanent(3) - this entry is currently in use and will remain so after the next reset of the bridge. deleteOnReset(4) - this entry is currently in use and will remain so until the next reset of the bridge. deleteOnTimeout(5) - this entry is currently in use and will remain so until it is aged out. |
RFC description
Defines managed objects for IEEE 802.1D MAC bridges connecting LAN segments, including bridge port state, spanning tree parameters, and forwarding database entries, as specified in RFC 1286.
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