On 6/19/08 10:44 PM, William Herrin allegedly wrote:
The requirement is that end users (meaning folks who operate servers in this case) be able to change service providers: 1. Without a major overall effort, and 2. Without requiring any changes outside of the end user's administrative control.
I don't believe the second one. First there's simple lower layer connectivity -- of course you need permission from a NSP if you want to receive traffic. Second there's routing. I see no way for packets to me to traverse an intermediate provider without at least some node under that provider's control being configured differently. If I use IP addressing, it has to know that my addresses are reached via a particular link, and a responsible NSP will not just believe a route some new customer tosses at it. If someone sending a packet to me encapsulates it all the way to a node I control, still the intermediate NSP needs to know what link to send the packet on. If I use connection setup of some kind, still there has to be some way for the intermediate NSP to know how to reach even just one (representative) node in my network. ... so changing your connectivity will always require changes by the network you are connecting to.
Under the circumstances, it is appropriate to escalate the solution (PI addresses) to requirement status. If at some point in the future someone demonstrates an workable architecture which unequivocally meets the original two requirements, we can just as easily reverse the escalation. Given the history, the onus should be entirely on the newcomer to demonstrate that they really have an in-practice workable solution that doesn't require PI.
PI is a solution, not a requirement. The requirements are easy multihoming and easy connectivity change.
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