IF-MIB::linkUp #
A linkUp trap signifies that the SNMP entity, acting in an agent role, has detected that the ifOperStatus object for one of its communication links left the down state and transitioned into some other state (but not into the notPresent state). This other state is indicated by the included value of ifOperStatus.
Variables #
- ifIndex
- ifAdminStatus
- ifOperStatus
Definitions #
- ifIndex
- A unique value, greater than zero, for each interface. It is recommended that values are assigned contiguously starting from 1. The value for each interface sub-layer must remain constant at least from one re-initialization of the entity’s network management system to the next re- initialization.
- ifAdminStatus
- The desired state of the interface. The testing(3) state indicates that no operational packets can be passed. When a managed system initializes, all interfaces start with ifAdminStatus in the down(2) state. As a result of either explicit management action or per configuration information retained by the managed system, ifAdminStatus is then changed to either the up(1) or testing(3) states (or remains in the down(2) state).
- ifOperStatus
- The current operational state of the interface. The testing(3) state indicates that no operational packets can be passed. If ifAdminStatus is down(2) then ifOperStatus should be down(2). If ifAdminStatus is changed to up(1) then ifOperStatus should change to up(1) if the interface is ready to transmit and receive network traffic; it should change to dormant(5) if the interface is waiting for external actions (such as a serial line waiting for an incoming connection); it should remain in the down(2) state if and only if there is a fault that prevents it from going to the up(1) state; it should remain in the notPresent(6) state if the interface has missing (typically, hardware) components.
Here is a runbook for the SNMP Trap # IF-MIB::linkUp:
Meaning #
The linkUp trap indicates that an interface on a network device has transitioned from a down state to an operational state. This trap is generated when the ifOperStatus object for an interface changes from down to up or another operational state.
Impact #
The impact of this trap is minimal, as it indicates that an interface is now operational and ready to transmit and receive network traffic. However, it can be useful for network administrators to know when an interface has come online, as it may indicate a recovery from a previously failed state.
Diagnosis #
To diagnose the cause of a linkUp trap, the following steps can be taken:
- Check the ifOperStatus value to determine the new operational state of the interface.
- Verify the ifAdminStatus value to ensure that the interface is administratively enabled.
- Check the interface configuration to ensure that it is properly configured.
- Verify that there are no faults or errors on the interface that would prevent it from operating correctly.
Variables to check:
- ifIndex: The unique index of the interface that triggered the trap.
- ifAdminStatus: The desired state of the interface (up, down, or testing).
- ifOperStatus: The current operational state of the interface (up, down, testing, dormant, or notPresent).
Mitigation #
No specific mitigation is required for a linkUp trap, as it is a normal part of network operation. However, to ensure that the interface remains operational, network administrators should:
- Continue to monitor the interface for any errors or faults.
- Verify that the interface configuration is correct and up-to-date.
- Perform regular maintenance and testing to ensure that the interface remains operational.