Usage Scenario
By default, when the status of an AC interface on a PE changes, the PE does not send MAC Withdraw messages to its peers. As a result, its peers are unaware of the fact that the CE connecting to that AC interface is unreachable. Subsequently, traffic bound to the CE gets lost before MAC addresses in the VSI age out. To solve this problem, run the
interface-status-change mac-withdraw enable command. Then, when the AC interface status changes, the PE sends a MAC Withdraw message to all its peers. After a peer receives the MAC Withdraw message, it clears MAC addresses in the VSI based on the MAC Withdraw message type.
- When the status of an AC interface changes from Up to Down or an AC interface in the Up state leaves a VSI, the PE sends MAC Withdraw messages with the 0x406 TLV type to its peers. Upon receipt, a peer clears the MAC addresses learned over the specified PW from the VSI.
- When the status of an AC interface changes from Down to Up or an AC interface in the Up state joins a VSI, the PE sends MAC Withdraw messages with the 0x404 TLV type to its peers. Upon receipt, a peer clears MAC addresses in the VSI.
Precautions
This command takes effect only after the mac-withdraw enable command is also used.