sentences:  where UDP-Lite is coupled with the AMR codec to give improved speech quality in lossy network conditions.Since most modern link layers protect the carried data with a strong cyclic redundancy check (CRC) and will discard damaged frames, making effective use of UDP Lite requires the link layer to be aware of the network layer data being carried.Since no current IP stacks implement such "cross-layer" interactions, making effective use of UDP-Lite currently requires specially modified device drivers.