フリー問題

問題文

A provider guards its link-state exchanges across a boundary link with a keyed digest, and each key on that link carries a time at which it starts being used and a time at which it stops. The final key set on that link now reaches the second of those times, and nothing has been put in its place. A runbook must state what the router does with the exchanges on that link from that moment, and where the parameters of the guard it applies were settled. Which pair should the runbook carry?

選択肢

1. The expiry drill instructs the dropout handling, and the keying record sits on the in-band provision now.
2. The expiry drill instructs the extension handling, and the keying record sits on the manual provision now.
3. The expiry drill instructs the dropout handling, and the keying record sits on the manual provision now.
4. The expiry drill instructs the extension handling, and the keying record sits on the in-band provision now.