> -----Original Message----- > From: Simon Perreault [mailto:simon.perrea...@viagenie.ca] > Sent: Wednesday, September 07, 2011 2:29 PM > To: nanog@nanog.org > Subject: Re: NAT444 or ? > > David Israel wrote, on 09/07/2011 04:21 PM: > > 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) > > What you're describing is known as "endpoint-independent mapping" > behaviour. It > is good for not breaking applications, not so good for scalability. RFC > 4787 section 4.1 makes it a MUST.
There are two dimensions of that scalability, of course: Endpoint-independent mapping means better scaling of the NAT itself, because it stores less state (slightly less memory for each active mapping and slightly less per-packet processing). This savings is exchanged for worse IPv4 utilization -- which I agree is not so good for scalability. -d
