collision detection.. but then there is a correction algorithm.. which makes it retransmit data.. just as layer 4 TCP would do...
there is no such thing as error correction in the true sense, you cannot correct corrupt packets or collided frames, you can only retransmit them.. which is what both layers do with their respective PDU's
there is an algorithm at data link layer that is used for error detection.when an error is
detected by data link layer it informs transport layer that retransmits the same frame.
if u say there is a correction algorithm at data link layer and retransmits the data in case
of error detection then plz refer me the book from where u got this information(book title,author and edition NO)and if u got this information from websites through google and posting here,then i will never agree to your words becouse i have seen many websites that have contradiction for the same topic.