We know that end to end error management is handled by TCP at the transport layer. So theoretically it is not necessary to implement error detection/correction at the link-layer – yet it is...

 We know that end to end error management is handled by TCP at the transport layer.  So theoretically it is not necessary to implement error detection/correction at the link-layer – yet it is implemented there.  Why is it beneficial to implement error detection/correction at the link layer as well as the transport layer?