ron@vsedev.VSE.COM (Ron Flax) (01/09/88)
Does anyone have experience using the KA9Q TCP/IP implementation with dialup asynchronous modems? I would like to connect remote sites, one running MS-DOS, and a Sun Workstation which supports SLIP. How does one go about establishing the connection? -- ron@vsedev.vse.com (Ron Flax) uucp: ..!uunet!vsedev!ron inet: vsedev!ron@uunet.uu.net
jbvb@ftp.UUCP (James Van Bokkelen) (01/10/88)
We were demoing our PC/TCP SLIP with a Telebit Trailblazer at the TCP/IP conference in December. If you want to do it on a large scale, there are some issues regarding how the Unix SLIP code deals with multiple dial-up hosts and multiple ports (IP address assignment), but these can be ignored if it is small scale. I have been told that the encapsulation that KA9Q uses on packet radio is essentially SLIP, so all you'd need to do is install a serial asynch driver. Don't try to use the serial handling in the BIOS, it is way too slow and flakey... James VanBokkelen FTP Software Inc.
karn@faline.bellcore.com (Phil R. Karn) (01/12/88)
> I have been told that the encapsulation that KA9Q > uses on packet radio is essentially SLIP, so all you'd need to do is install > a serial asynch driver. Don't try to use the serial handling in the BIOS, > it is way too slow and flakey... The KA9Q package supports the same SLIP that everybody knows (and loves?) There is no support for dialing a modem; this has to be done by first running a separate (e.g., PROCOMM) and then bringing up net.exe. The packet radio encapsulation you mention is a special use of SLIP that is actually used only between the host PC and an external radio interface box called a "TNC" (Terminal Node Controller) that has been reprogrammed to operate as a simple asynch/synch frame format translator. (We call this the "KISS TNC" as an editorial comment on the everything-including-the-kitchen-sink firmware that normally runs on TNCs). The protocol actually spoken on the air is synchronous HDLC, complete with flags, bitstuffing and CRCs. The frame headers are unique to amateur radio, however; they carry our amateur radio callsigns as link level addresses. Somewhat simplified, the frames look like this: ___________________________________________________________________ FLAG|Dest Callsign|Source Callsign|CTL|TYPE=IP|IP datagram|CRC|FLAG ------------------------------------------------------------------- 7 bytes 7 bytes 1 1 variable 2 The resemblance to Ethernet encapsulation was intentional. We even use ARP to resolve IP addresses to callsigns. Phil