nanog mailing list archives

Re: TOS history?


From: "Dana Hudes" <dhudes () panix com>
Date: Tue, 22 Feb 2000 09:06:52 -0500


thanks for the information all, and to Ping Pan for reminding me that we used to support TOS on the Milford router. I 
vaguely recall now that was a feature added late in the product lifecycle, so may have only been available on the IBM 
Global Network. It is a trivia problem at this point. I have sufficient material to revise my lecture notes.
Although I want to point out that low delay is RFC 791 back in 1981.
It had precedence and TOS specified. I know all routers support the precedence field, and its interesting
about the use of TOS and low delay to avoid dial-up links where possible.

Dana

----- Original Message ----- 
From: "William Allen Simpson" <wsimpson () greendragon com>
To: "Dana Hudes" <dhudes () panix com>
Cc: <nanog () merit edu>
Sent: Tuesday, February 22, 2000 5:32 AM
Subject: Re: TOS history?



Dana Hudes wrote:

Was this something actually supported in the Internet? Widely? any examples of who?
Around when did it stop being supported?
Did anyone ever actually support RFC1349 in a host or router?

Yes, on the half-dozen or so routers that I worked on, the low delay bit 
was supported.  This was especially important for dial-up links.
(NetBlazer, Lan'sEnd, etc., none of which are in much use today.)

I have also _set_ the low delay bit for telnet traffic on those boxen,
but you don't telnet out of routers very often.

I'd have to check the source, but I'm pretty sure I put at least some 
of that stuff in Qualcomm/Sony cell phones and base stations, so it 
might still be in use today.

I have also used the TOS bits in a weighted fair queuing scheme.

I never figured out how "high reliability" would be implemented.  I just 
tried to never have low reliability. :-)

WSimpson () UMich edu
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32





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