Bridge MIB

# VLAN list

Each Virtual LAN is a bridge. The list shows VLAN IDs and names defined in this device. To view a particular VLAN's bridge attributes, select it in the list.

# Edit Bridge

BaseBridgeAddress. 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.

BaseNumPorts. The number of ports controlled by this bridging entity.

BaseType. 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.

StpProtocolSpecification. An indication of what version of the Spanning Tree Protocol is being run.

StpPriority. The value of the writeable 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.

StpTimeAtTopologyChange. The time (in hundredths of a second) since the last time a topology change was detected by the bridge entity.

StpTopChanges. The total number of topology changes detected by this bridge since the management entity was last reset or initialized.

StpDesignatedRoot. The bridge identifier of the root of the spanning tree as determined by the Spanning Tree Protocol as executed by this node.

StpRootCost. The cost of the path to the root as seen from this bridge.

StpRootPort. The port number of the port that offers the lowest cost path from this bridge to the root bridge.

StpMaxAge. 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.

StpHelloTime. 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.

StpHoldTime. 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.

StpForwardDelay. 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 each of the Listening and Learning states, which precede the Forwarding state. This value is also used when a topology change has been detected and is underway to age all dynamic entries in the Forwarding Database.

StpBridgeMaxAge. The value that all bridges use for MaxAge when this bridge is acting as the root. Note that 802.1D-1990 specifies that the range for this parameter is related to the value of dot1dStpBridgeHelloTime. The granularity of this timer is specified by 802.1D-1990 to be 1 second. An agent may return a badValue error if a set is attempted to a value that is not a whole number of seconds.

StpBridgeHelloTime. 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- 1990 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.

StpBridgeForwardDelay. The value that all bridges use for ForwardDelay when this bridge is acting as the root. Note that 802.1D-1990 specifies that the range for this parameter is related to the value of dot1dStpBridgeMaxAge. The granularity of this timer is specified by 802.1D-1990 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.

TpLearnedEntryDiscards. The total number of Forwarding Database entries, which have been or would have been learned, 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.

TpAgingTime. The timeout period in seconds for aging out dynamically learned forwarding information. 802.1D-1990 recommends a default of 300 seconds.

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# Transparent Bridge Forwarding Database

Address. A unicast MAC address for which the bridge has forwarding and/or filtering information.

Port. 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.

Status. The status of this entry. The meanings of the values are:

1. learned: the value of the corresponding instance of dot1dTpFdbPort was learned, and is being used.
2. self: 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.
3. mgmt: the value of the corresponding instance of dot1dTpFdbAddress is also the value of an existing instance of dot1dStaticAddress.

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# Static (Destination-Address Filtering) Database

Address. The destination MAC address in a frame to which this entry's filtering information applies.

ReceivePort. 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.

AllowedToGoTo. 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.) The default value of this object is a string of ones of appropriate length.

Status: This object indicates the status of this entry. The default value is permanent:

1. permanent: this entry is currently in use and will remain so after the next reset of the bridge.
2. deleteOnReset: this entry is currently in use and will remain so until the next reset of the bridge.
3. deleteOnTimeout: this entry is currently in use and will remain so until it is aged out.

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#

# Bridge Spanning Tree

Priority. 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.

State. 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).

Enable. The enabled/disabled status of the port.

DesignatedRoot. 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.

DesignatedCost. 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.

DesignatedBridge. The Bridge Identifier of the bridge which this port considers to be the Designated Bridge for this port's segment.

DesignatedPort. The Port Identifier of the port on the Designated Bridge for this port's segment.

ForwardTransitions. The number of times this port has transitioned from the Learning state to the Forwarding state.

MaxInfo. The maximum size of the INFO (non-MAC) field that this port will receive or transmit.

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# Graph Bridge

DelayExceededDiscards. 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.

MtuExceededDiscards. The number of frames discarded by this port due to an excessive size. It is incremented by both transparent and source route bridges.

InDiscards. Count of valid frames received which were discarded (i.e., filtered) by the Forwarding Process.

ForwardTransitions. The number of times this port has transitioned from the Learning state to the Forwarding state.

InFrames. 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, including bridge management frames.

OutFrames. 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, including bridge management frames.

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