Positive mask, negative mask, wildcard

Positive mask

1  On behalf of the match ,0  For any ,1  and 0  Do not cross

example ：IP  Address

Unmask

1  On behalf of the match ,0  For any ,1  and 0  Do not cross

example ：OSPF  Declare

wildcard

0 On behalf of the match ,1  For any ,1  and 0  Can cross appear

example ：ACL

Usage example ：192.168.1.0/24, Match all odd numbers separately 、 Even host

Odd number ：192.168.1.1,0.0.0.254

even numbers ：192.168.1.0,0.0.0.254