What Chapter 13 provision allows for the “stripping” of unsecured liens? And, when is the lien actually stripped?

Chapter 13 debtor may strip unsecured lien under Code § 1322(b)(2), but not § 506(d). Further, stripping an unsecured lien in Chapter 13 requires that debtor receive discharge. A lien cannot be avoided before the Chapter 13 debtor’s discharge is entered.