Michael Mealling wrote: > Its not that 'we don't want to change because its to much > work'. Its that the Internet architecture assured us that the > hour glass model applied, that the network topology would > remain abstracted within what to us is an opaque address > space. One of the number one reasons its so easy for new > application layer technologies to be deployed is that a > developer doesn't need to know or care about any layer below > TCP (or, in rare cases, UDP). If the lower layers want to > change that hour glass model then we're talking about a > serious breach of contract with the layers above it and a > dangerous blow to the hour glass model. You really don't want to go there, since it is in fact the violation of the layering by the apps that has created some of the mobility and renumbering challenges. Apps know all too much about what is going on below them, which is why the app developer sees any change as a lot of work. Tony