CiscoでのMPLS-TEで、バックアップトンネルへのFRRを使っている箇所で、稼動系トンネルにexplicit pathを二つ書く意味って何かありますか？
たとえばこんな感じで
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interface Tunnel1
tunnel destination 5.5.5.5
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng path-option 1 explicit id 1
tunnel mpls traffic-eng path-option 2 explicit id 2
tunnel mpls traffic-eng fast-reroute
interface Tunnel99
tunnel destination 5.5.5.5
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng path-option 1 explicit id 9
int g0/0/1
ip address 1.1.1.1 255.255.255.252
mpls traffic-eng tunnels
mpls traffic-eng backup-path Tunnel99
int g0/0/2
ip address 2.2.2.1 255.255.255.252
mpls traffic-eng tunnels
!
ip explicit-path name id 1 enable
next-address 1.1.1.2
ip explicit-path name id 2 enable
next-address 2.2.2.2
next-address 3.3.3.2
next-address 4.4.4.2
ip explicit-path name id 9 enable
next-address 2.2.2.2
next-address 3.3.3.2
next-address 4.4.4.2