Which of the following commands configures primary and fallback link groups for Cisco PfR? (Select the best answer.)

A. border
B. link-group
C. pfr-map

D. set link-group

Explanation:

The set link-group command configures primary and fallback link groups for Cisco Performance Routing (PfR). The syntax of the set linkgroup command is set linkgroup primarylinkgroupname [fallbackfallbacklinkgroupname]. Link groups enable you to configure a set of exit interfaces as preferred or standby links to optimize traffic classes in a PfR policy. Primary and fallback link groups are configured on the master controller.
The border command does not configure primary and fallback link groups. Instead, the border command is issued on the master controller in order to configure a border router. A master controller can control up to 10 border routers. In small environments, the master controller and the border router will be the same device. The syntax of the bordercommand is borderipaddress [keychain keychainname], where ipaddress is the IP address of the border router.
The linkgroup command does not configure primary and fallback link groups. Instead, the linkgroup command configures a border router exit interface as a member of a link group. Up to three link groups can be specified on an interface. The syntax of the linkgroup command is linkgroup linkgroupname [linkgroupname [linkgroupname]].
The pfrmap command does not configure primary and fallback link groups. Instead, the pfrmap command configures a PfR map. The syntax of the pfrmap command is pfrmap mapname sequencenumber. Issuing the pfrmap command places the router into pfrmap configuration mode. In this mode, you will configure a match clause with the match command and specify the primary and fallback link groups with the set linkgroupcommand. Only one match command can be configured for a PfR map sequence.