glen@aecom.YU.EDU (Glen M. Marianko) (02/21/89)
Here at Einstein College we are using NI5210 boards with Interlan's packet driver for Novell Netware and FTP's TCP/IP. From what I casually understand about the packet driver, it is designed to filter packets (by type field?) and send them to the appropriate software stack for processing. Now, what happens if there are two stacks that would like to listen to the same protocol. As an example, FTP's telnet and NCSA telnet on the same NIC through the same driver. Is this possible either a) as far as the packet driver spec is concerned with "in theory", or b) if the software was written appropriately? In other words, how far can one stretch the one NIC anyway? -- Glen Marianko glen@aecom.yu.edu
jbvb@VAX.FTP.COM (James Van Bokkelen) (02/25/89)
The Packet Driver was intended to do one level of demultiplexing, and all but one of the existing drivers do that at the MAC layer (according to the Ethertype field). The one exception does its demultiplexing according to the IP protocol byte. This still uses datagrams, and is about the highest level you can use a simple spec like the Packet Driver with. So, nothing that exists would deal with the case you propose. I would say that this case isn't a particularly likely one, because it implies two TCPs in the same machine (which has been done, but requires really odd split-level multiplexing/demultiplexing). If you are working with FTP's v2.0, and want to use the NCSA user interface, I'd recommend removing the transport layer from the NCSA, and re-writing it to call our kernel via Int 61 (our kernel provides a shareable multi-connection TCP as a TSR system service). James B. VanBokkelen 26 Princess St., Wakefield, MA 01880 FTP Software Inc. voice: (617) 246-0900 fax: (617) 246-0901