AS65002
                   \
            AS65001 \          AS65001
               main  \         backup
                   \  \       / 
                    \  \     /
                     \  \   /
                      \  \ / 
                    /---------\
                    |         |
                    | border  |
                    | AS65100 |
                    \---------/

AS65100, AS65001 and AS65002 are illustrating numbers. Actually, these are real allocated AS numbers to Swiss providers.

AS65001 main link is on Gigabit3/0/0.911 (dot1Q 911)
AS65002 link is on Gigabit 3/0/0.921 (dot1Q 921)

AS65001 backup is on Gigabit3/1/0.912 (dot1Q 912)