Prefix expansion is one of the keys of this algorithm,
since it improves the speed dramatically by adding redundancy.
+Deletion
+~~~~~~~~
+
+When deleting a rule, a replacement rule is searched for. Replacement rule is an existing rule that has
+the longest prefix match with the rule to be deleted, but has shorter prefix.
+
+If a replacement rule is found, target tbl24 and tbl8 entries are updated to have the same depth and next hop
+value with the replacement rule.
+
+If no replacement rule can be found, target tbl24 and tbl8 entries will be cleared.
+
+Prefix expansion is performed if the rule's depth is not exactly 24 bits or 32 bits.
+
+After deleting a rule, a group of tbl8s that belongs to the same tbl24 entry are freed in following cases:
+
+* All tbl8s in the group are empty .
+
+* All tbl8s in the group have the same values and with depth no greater than 24.
+
+Free of tbl8s have different behaviors:
+
+* If RCU is not used, tbl8s are cleared and reclaimed immediately.
+
+* If RCU is used, tbl8s are reclaimed when readers are in quiescent state.
+
+When the LPM is not using RCU, tbl8 group can be freed immediately even though the readers might be using
+the tbl8 group entries. This might result in incorrect lookup results.
+
+RCU QSBR process is integrated for safe tbl8 group reclamation. Application has certain responsibilities
+while using this feature. Please refer to resource reclamation framework of :ref:`RCU library <RCU_Library>`
+for more details.
+
Lookup
~~~~~~