PBF rules allow traffic to take an alternative path
from the next hop specified in the route table, and are typically
used to specify an egress interface for security or performance
reasons. Let's say your company has two links between the corporate office
and the branch office: a cheaper internet link and a more expensive
leased line. The leased line is a high-bandwidth, low-latency link.
For enhanced security, you can use PBF to send applications that
aren’t encrypted traffic, such as FTP traffic, over the private
leased line and all other traffic over the internet link. Or, for
performance, you can choose to route business-critical applications
over the leased line while sending all other traffic, such as web
browsing, over the cheaper link.