nanog mailing list archives
Re: NAT444 or ?
From: David Israel <davei () otd com>
Date: Wed, 07 Sep 2011 16:21:35 -0400
On 9/7/2011 3:24 PM, Seth Mos wrote:
I think you have the numbers off, he started with 1000 users sharing the same IP, since you can only do 62k sessions or so and with a "normal" timeout on those sessions you ran into issues quickly.
Remember that a TCP session is defined not just by the port, but by the combination of source address:source port:destination address:destination port. So that's 62k sessions *per destination* per ip address. In theory, this particular performance problem should only arise when the NAT gear insists on a unique port per session (which is common, but unnecessary) or when a particular destination is inordinately popular; the latter problem could be addressed by increasing the number of addresses that facebook.com and google.com resolve to.
I'm not advocating CGN; my point is not that this problem *should* be solved, merely that it *can* be.
-Dave
Current thread:
- Re: CGN and CDN (was Re: what about the users re: NAT444 or ?), (continued)
- Re: CGN and CDN (was Re: what about the users re: NAT444 or ?) Alexander Harrowell (Sep 09)
- Re: CGN and CDN (was Re: what about the users re: NAT444 or ?) Christian de Larrinaga (Sep 09)
- Re: CGN and CDN (was Re: what about the users re: NAT444 or ?) Dobbins, Roland (Sep 09)
- RE: what about the users re: NAT444 or ? Dan Wing (Sep 08)
- Re: what about the users re: NAT444 or ? Christian de Larrinaga (Sep 09)
- Re: what about the users re: NAT444 or ? Owen DeLong (Sep 13)
- RE: what about the users re: NAT444 or ? Dan Wing (Sep 13)
- Re: what about the users re: NAT444 or ? Owen DeLong (Sep 14)
- Re: NAT444 or ? Mark Tinka (Sep 10)
- Re: NAT444 or ? Jean-Francois . TremblayING (Sep 07)
- Re: NAT444 or ? David Israel (Sep 07)
- RE: NAT444 or ? Leigh Porter (Sep 07)
- Re: NAT444 or ? Mike Jones (Sep 08)
- Re: NAT444 or ? Carlos Martinez-Cagnazzo (Sep 08)
- RE: NAT444 or ? Leigh Porter (Sep 09)
- Re: NAT444 or ? Randy Bush (Sep 09)
- RE: NAT444 or ? Dan Wing (Sep 08)
- Re: NAT444 or ? Owen DeLong (Sep 13)
- RE: NAT444 or ? Dan Wing (Sep 13)
- Re: NAT444 or ? Simon Perreault (Sep 07)
- RE: NAT444 or ? Dan Wing (Sep 08)