Subject: Re: [Softwires] Preparation for a discussion on 'statelessmotivations' at the Quebec meeting

From: <[email-masked]>
Date: Fri, 8 Jul 2011 15:50:57 +0800

For example, no logging has been presented as a strong reason to do sateless. However, no logging can be achieved
		with static port allocation on a centralized NAT. On this particular logging point, there are no obvious differences between the
		'distributed on CPE' NAT solution and the centralized NAT solution. 
		 
		To my understand, no logging is one of benifits among others. 
		In addition, note that even if a centralized NAT configuered with static port allocation, the centralized NAT still needs to maintain per-flow state (NAT entires)! 

	As you point out, the "no logging" part is really a function of the use of a static mapping to a range of ports. Any centralized NAPT function can use static mapping. When you use static mapping, then you get all the pros and cons that go along with it.

		More generally, it seems that what is described as a 'stateless' solution should be characterized as a
		'distributed state' solution. As such, the tradeoff of maintaining the state centrally vs globally
		needs to be analyzed.

	
	"stateless operation" if you prefer. The point is that within the ISP network, there is no per-flow state that resides on any single endpoint running the protocol in question.  So, config can be static, and BRs can be reached via anycast. That's the heart of a stateless solution. Just like 6rd, if you will.  
	 
	I like this point! No per-flow state is the heart.     

	Section 18: Single Points of Failure - here, stateless wins pretty much hands down as it is not introducing any new single points of failure. 
	 
	One hand. 
	
	-Xiaohong
	open source PCP Client,
	open source A+P
	http://opensourcev6transtechnologies.weebly.com/