[c-nsp] Access-list Question

[Tony Li]

On May 15, 2007, at 10:00 PM, Brian McMahon wrote:

> My personal theory (SWAG) is that, long ago in the Elder Days of
> single-digit IOS version numbers, some clever programmer figured out
> a way to save a couple of processor cycles per ACL by coding the
> bitmask this way around -- an efficiency gain that has been easily
> swamped over the years by the confusion it's created, but that is now
> WAY TOO LATE to fix.


Close.  You have the timing right.  The modeling was based on "don't  
care bits" as commonly found in hardware design.  Netmasks hadn't  
really caught on as of then.

Tony