On 27/04/2016 08:28, Adrian Farrel wrote: ... > Section 6 > Include hint on best practice for top and bottom of ranges. > OLD > Reserved: Not assigned and not available for assignment. Reserved > values are held for special uses, such as to extend the > namespace when it becomes exhausted. Note that this is > distinctly different from "Unassigned". > NEW > Reserved: Not assigned and not available for assignment. Reserved > values are held for special uses, such as to extend the > namespace when it becomes exhausted. Note that this is > distinctly different from "Unassigned". > > It is common practice for documents that define numeric registries > to mark the zero value as "Reserved" because this often aids protocol > implementations. I'm not sure about the "because" clause. It sounds a bit like an excuse for sloppy coding. Defining it explicitly as a no-op would seem like better practice in many cases. Brian > It is also common practice to mark the maximum > value as "Reserved" so that it can be used as part of a strategy to > extend the registry if the range proves too small in the future. > END > > Thanks, > Adrian > >