Two frame filters are provided to identify frames belonging to either SR Class A or SR Class B. In order to access the SR Class A filter, the Filter Index shall set to 1 in the Frame Filter Control Register (see Table 4). The SR Class B frame filter can be accessed by setting Filter Index to 2.
The output of the two filters is combined so that a match against either filter allows AV traffic to pass. If only one SR Class is supported then either disable the undesired filter or set both filters to the same value.
The default behavior of the SR Class frame filters is to match both the default VLAN PCP and VLAN ID values for that SR Class, as follows:
SR Class A:
Type = 0x0081 (VLAN)
Type_info = 0x0260 (VLAN PCP = 3 VLAN ID = 2)
SR Class B:
Type = 0x0081 (VLAN)
Type_info = 0x0240 (VLAN PCP = 2VLAN ID = 2)
This translates to the register settings in Table 1 to Table 4.