A flag that decides whether the last authentication key on expiry, should take its lifetime to be infinite or not. If this object is set to true the last key on expiry resets its lifetime to be infinite and continues to be the Key until new Authentication key id is configured. If this object is configured to be false, then it should not send RIP updates once the last key is expired. The received RIP updates from the peer will be dropped after the last available key has expired and the object is set not TRUE. TRUE - The last key will be treated as having infinite life time. FALSE - After the last key expires, the received RIP updates will be dropped and the routes may tear down. No updates will be sent on that interface.