Dear reader, I'm not updating these pages anymore. If you have tc or ip related questions, you can post them on the LARTC mailing list.

From help-file :
U32 classifier
  If you say Y here, you will be able to classify outgoing packets
  according to their destination address. If unsure, say Y.
  This code is also available as a module called cls_u32.o ( = code
  which can be inserted in and removed from the running kernel
  whenever you want). If you want to compile it as a module, say M
  here and read Documentation/modules.txt