[103529] in North American Network Operators' Group
"Does TCP Need an Overhaul?" (internetevolution, via slashdot)
daemon@ATHENA.MIT.EDU (Paul Vixie)
Fri Apr 4 21:52:18 2008
From: Paul Vixie <paul@vix.com>
To: nanog@merit.edu
Date: Sat, 05 Apr 2008 01:51:27 +0000
Errors-To: owner-nanog@merit.edu
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
equipment:
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
unfairness
...
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.
