Consider:
In the US, a person cannot be discriminated against based on race,
color, religion, sex, or national origin.
When referring to a factor on which a decision or action is based, we refer to the factor in the singular. We do not say "based on races, colors, religions, sexes, or national origins". That the decision or action may affect many individuals (the entire population in my example, all packets in the domain in the OP's example) is not relevant, because we are referring to the factor as factor.
discriminated against .... based on {list of factors}
deliver frames ... based on {factor}
I chose the car based on color.
I may have looked at quite a few cars having a variety of colors, but the factor or criterion on which I based my choice was color.
P.S. See this related answer. We are referring not to the property content (e.g. "blue") but to the property generically or in abstract terms as attribute. Which attribute of the car did I base my choice on? Top speed? Number of doors? Fuel-economy? Reliability rating? Color?