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Date: Mon, 21 Oct 91 22:44:58 EDT From: sommerfeld@apollo.com (Bill Sommerfeld) To: vaf@Valinor.Stanford.EDU Cc: yakov@watson.ibm.com, steve@ncri.cise.nsf.gov, com-priv@psi.com In-Reply-To: Vince Fuller's message of Monday, October 21, 1991 10:20:18 pm (EDT) Date: Monday, October 21, 1991 10:20:18 pm (EDT) From: vaf@Valinor.Stanford.EDU (Vince Fuller) Office: Pine Hall 167, (415) 723-6860 This is not a solution, since it is the content, not the source/destination, which determines whether a given packet is commercial or not. The only entity which can properly set the TOS is the user. What happens if the user (a) makes a mistake? (b) doesn't understand the difference? (c) doesn't care? The "easy" solution to this problem is to use a special TOS bit (or combination) to indicate "commercial/research" and modify each application to set the bit appropriately based on user input. Again, the "easy" way to accomplish this is to make a special "commercial" version of each application that sets the appropriate TOS bit (i.e. "ctelnet", "cftp", etc.). I say "easy" in quotes since doing this creates a user education problem, Sorry. This is much more than just a user-education problem. What about all those systems out there running "old" binary-only IP implementations which don't let you set TOS? What about distributed systems where it's painful to pass information down under the covers to indicate what the appropriate TOS is? How do you pass the appropriate TOS to named on each lookup? Does named have to maintain separate caches for each TOS? How do you pass an appropriate TOS down through the kernel to NFS or AFS? There are a large number of sites out there where there is an appropriate "default" for commercial vs. research. And it's not going to be the same. If you grab two TOS bits, 10 means "research", 01 means "commercial", and 00 means "site default"; "site default" gets converted to 01 or 10 by an appropriate firewall router on the way out. The end user can set 10 or 01 if necessary and possible; otherwise, the router does it for him. - Bill
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