melohn@SUN.COM.UUCP (12/16/86)
Speaking as an admittedly biased source, the Sun Datacomm group has managed to implement OSI (MAP/TOP) with a minimum of kernel changes using the basic protosw, ioctl facility, and even the routing table routines from the standard SunOS. We also have implementations of X.25, SNA, and DECnet which all use the ifnet structure to layer different protocol instances on top of different datalinks (HDLC, SDLC, 802.x). As you might expect, the farther your protocol is from the TCP/IP model, the less useful the standard networking code will be. If your goal is XNS under Unix, it makes sense to use the 4.3 implementation. As a general platform for protocol/network development, we believe SunOS offers most of the facilities you need.