"Does TCP Need an Overhaul?" (internetevolution, via slashdot)

Paul Vixie paul at vix.com
Sat Apr 5 01:51:27 UTC 2008

in <http://www.internetevolution.com/author.asp?section_id=499&doc_id=150113>
larry roberts says:

	..., last year a new alternative to using output queues, called "flow
	management" was introduced. This concept finally solves the TCP
	unfairness problem and leads to my answer: Fix the network, not TCP.


	What is really necessary is to detect just the flows that need to slow
	down, and selectively discard just one packet at the right time, but
	not more, per TCP cycle. Discarding too many will cause a flow to
	stall -- we see this when Web access takes forever.

	Flow management requires keeping information on each active flow,
	which currently is inexpensive and allows us to build an intelligent
	process that can precisely control the rate of every flow as needed to
	insure no overloads. Thus, there are now two options for network

	 o Random discards from output queues bIntelligent rate control of
	   every flow -- creates much TCP unfairness

	 o Intelligent rate control of every flow -- eliminates most TCP


i wouldn't want to get in an argument with somebody who was smart and savvy
enough to invent packet switching during the year i entered kindergarden,
but, somebody told me once that keeping information on every flow was *not*
"inexpensive."  should somebody tell dr. roberts?

(i'd hate to think that everybody would have to buy roberts' (anagran's)
Fast Flow Technology at every node of their network to make this work.  that
doesn't sound "inexpensive" to me.

More information about the NANOG mailing list