Note:
This interpretation of DiffServ predates the RFC 2474/2475 DiffServ specification.
The Passport 1000 Series switch software provides the capability of setting the bits in the ToS precedence bits of the IP header by using an IP filter mechanism. The DiffServ dialog box allows you to set the decimal values that are used in an IP protocol filter to set or protect the bits in the ToS field.
The IP filter mechanism uses the AndMask and one of three OrRules to change the ToS precedence bits. First you must enter values in the AndMask and one or more OrRules. Next you choose which OrRule to apply.