Absolute and sliding expiration are two Time based expiration strategies.
Absolute Expiration: Cache in this case expires at a fixed specified date or time. Example: Cache. Insert("ABC", ds, null, DateTime.Now.AddMinutes(1), Cache.NoSlidingExpiration); The cache is set to expire exactly two minutes after the user has retrieved the data.
Sliding Expiration: the cache duration increases in this case by the specified sliding expiration value every time the page is requested. More a page is requested it will remain in cache, whereas a less requested page will not remain in cache. Example: Cache.Insert("ABC", ds, null, Cache.NoAbsoluteExpiration, TimeSpan.FromMinutes(1));