tcp limitations

[Brad Knowles]

At 4:26 PM +0200 6/12/01, Guy Pazi wrote:

>  But, lets say for a minute, all queries were tcp. What ~ number of
>  queries/sec will a root name server support drop down to, from the 2-5k udp
>  queries/sec?

	Well, if you read the web page at 
<http://cider.caida.org/~evi/sigcomm/paper.html> (which was recently 
mentioned here), you will note that a.root-servers.net actually 
handles on the order of 12,000 queries per second.

	Even if everything else went perfectly, using TCP would probably 
cut your ability to handle queries by a factor of ten, given the TCP 
3-way setup handshake, the connection tear down, and then doing all 
of this in many multiple packets when a single UDP packet (and a 
single UDP response) would have sufficed.


	So, on a more normal box that could otherwise handle ~2500 
queries per second, you'd probably be taking it down to being able to 
handle only ~250 TCP-only queries per second.

	This way lies madness.

-- 
Brad Knowles, <brad.knowles at skynet.be>

/*        efdtt.c  Author:  Charles M. Hannum <root at ihack.net>          */
/*       Represented as 1045 digit prime number by Phil Carmody         */
/*     Prime as DNS cname chain by Roy Arends and Walter Belgers        */
/*                                                                      */
/*     Usage is:  cat title-key scrambled.vob | efdtt >clear.vob        */
/*   where title-key = "153 2 8 105 225" or other similar 5-byte key    */

dig decss.friet.org|perl -ne'if(/^x/){s/[x.]//g;print pack(H124,$_)}'