YAKOV@IBM.COM (Jacob Rekhter) (10/23/87)
The reason why MTU of 508 bytes is mentioned in RFC is that IN THEORY (!!!!) MAC Layer bridge architecture allows bridge to restrict frame size to 552 bytes (508 MTU IP). However, I doubt, that in real life we are going to see this phenomena. It was mentioned in RFC JUST FOR COMPLETENESS. In real life IP works over 802.5 with MAC layer bridges JUST FINE. Jacob Rekhter (Yakov@IBM.COM)