Take it as a given that it *will* slip the schedule some amount, because the resources for a 240/4 feature will have to come from somewhere. So how much slippage are you willing to accept?
OK, assuming on the order of 5 lines of code, let's allow 1 day for meetings to decide to do this, one day to change the code and get the change signed off, and 1 day to do regression testing. That makes a total of 3 days slippage for IPv6 features in the worst case. Earlier in the thread we were told that releasing 240/4 could only buy us an extra year of time. Let's assume that was overly optimistic and it will only buy one twelfth of that, i.e. an extra month before IPv4 exhaustion. Seems to me that spending 3 days to get back 30 days is a very profitable proposition. Clearly, slippage of IPv6 features is not a problem and it is not a problem precisely because the proposal is to release these 240/4 addresses to have exactly the same default unicast behavior as the majority of the IPv4 space. --Michael Dillon P.S. I hope that the issues discussed on this thread will be picked up by the authors of draft-fuller because I think there is enough here to make an update to the draft worthwhile.