 are an excellent example; they are based on nonintrusive interleaving technique and leave the search path unobstructed while external sources are engaged with the introduction of new table entries. Of course, this flexibility causes a significant increase in the CAM pin count, board real estate, and signals to route to the appropriate place. For more budget-conscious designs, two-port designs must be used where table maintenance can usually occur when a search is not occurring. However, table maintenance is not just about introducing updates into the table. It may also involve relocating entries or even entire tables to different parts of the CAM because too much empty space may have been created between subtables following the continuous updating of entries. An example where this problem arises is in Classless Interdomain Routing (CIDR) (RFC 1519) routing, which was the longest-prefix match (LPM) algorithm, which is used in CIDR. The routes used in this scheme are described as a prefix and a prefix length. When a search is conducted (if the table has been prop- erly structured and maintained), the location of the entry will produce the LPM. If the table must be reshuffled because one segment is full, extra operations are required that eat up time. This is a critical factor when developing applications that must respect and sustain traffic arriving at wire speed. A read and write operation is used for every entry word that must be relocated. If the start addresses of entire blocks must be readjusted following such moves, the corresponding mask word must be reloaded each time-this also involves a read/write sequence. The software designer, who in this context is predominantly concerned about the search capabilities of his or her implementation, must take all these issues under consideration to ensure that production code remains robust under these circumstances. From a user's point of view, searches cannot be affected simply because tables must be reshuffled. To further show the impact of efficient table lookups 