The simplest way to map the 30 bit main memory address to the 17 bit cache address is to use the lower 17 bits of the physical (main memory) address. TLBs have no offset! An entry is a page number. A translation lookaside buffer (TLB) is a memory cache that is used to reduce the time taken to. Translation Lookaside Buffer (TLB) is nothing but a special cache used to keep track of recently used transactions.