All MIBs › BRIDGE-MIB › dot1dBasePortIfIndex
dot1dBasePortIfIndex
Module: BRIDGE-MIB
OID (symbolic): BRIDGE-MIB::dot1dBasePortIfIndex
OID (numeric): 1.3.6.1.2.1.17.1.4.1.2
Node type: OBJECT-TYPE
Type: InterfaceIndex
Access: read-only
Description: Interface index for this port.
What is dot1dBasePortIfIndex?
This read-only object maps a bridge port to its corresponding interface index in the standard IF-MIB, allowing operators to correlate bridge-level forwarding behavior with physical interface statistics. This linkage is essential for correlating bridging errors and performance metrics with specific network ports. It enables a unified view of both switching and interface-level diagnostics.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.2.1.17.1.4.1.2 snmpwalk -v2c -c public <target> BRIDGE-MIB::dot1dBasePortIfIndex
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.2.1.17.1.4.1.2.1 snmpget -v2c -c public <target> BRIDGE-MIB::dot1dBasePortIfIndex.1
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OID Breakdown
Upper-level ancestors (6 from the standard OID tree / other modules)
| Numeric OID | Name | Module |
|---|---|---|
| 1 | iso | LANART-AGENT |
| 1.3 | org | AirPair-MIB |
| 1.3.6 | dod | AirPair-MIB |
| 1.3.6.1 | internet | AirPair-MIB |
| 1.3.6.1.2 | mgmt | AXON-MIB |
| 1.3.6.1.2.1 | mib_2 | AXON-MIB |
| Numeric OID | Name | Module |
|---|---|---|
| 1.3.6.1.2.1.17 | dot1dBridge | BRIDGE-MIB |
| 1.3.6.1.2.1.17.1 | dot1dBase | BRIDGE-MIB |
| 1.3.6.1.2.1.17.1.4 | dot1dBasePortTable | BRIDGE-MIB |
| 1.3.6.1.2.1.17.1.4.1 | dot1dBasePortEntry | BRIDGE-MIB |
| 1.3.6.1.2.1.17.1.4.1.2 | dot1dBasePortIfIndex | BRIDGE-MIB |
FAQ
Why do I need dot1dBasePortIfIndex if I already have the bridge port number?
The bridge port number is only meaningful within the bridging tables — STP state, forwarding, and so on. dot1dBasePortIfIndex bridges that number to the ifIndex used everywhere else in SNMP: interface counters, link status, descriptions — so you can tell a NOC engineer 'port 4 in Spanning Tree is physically interface Gi1/0/4', not just an abstract bridge port ID.
A port shows as blocking in Spanning Tree — how do I find out which physical interface that is?
Look up the bridge port number in dot1dStpPortState, then use dot1dBasePortIfIndex for that same port row to get the ifIndex, and finally check ifDescr or ifName for that ifIndex in IF-MIB to get the human-readable interface name.