AS path prepend

[Roel Reyes]

what's the advantage of using this sequence of config? why not simply prepend Upstream2 and dont prepend Upstream1

ip prefix-list Upstream1 description IP Block Incoming Traffic
ip prefix-list Upstream1  seq 20 permit 192.168.0.0/24
ip prefix-list Upstream1  seq 30 permit 192.168.1.0/24
ip prefix-list Upstream1  seq 40 permit 192.168.2.0/24
ip prefix-list Upstream1  seq 50 permit 192.168.3.0/24
ip prefix-list Upstream1 seq 100 deny 0.0.0.0/0 le 32
!
ip prefix-list Upstream1 -2 description IP Block Incoming Traffic
ip prefix-list Upstream1 -2 seq 100 deny 0.0.0.0/0 le 32
!
ip prefix-list Upstream1 -3 description IP Block Incoming Traffic
ip prefix-list Upstream1 -3 seq 100 deny 0.0.0.0/0 le 32
!
ip prefix-list Upstream2 description IP Block Incoming Traffic
ip prefix-list Upstream2 seq 100 deny 0.0.0.0/0 le 32
!
ip prefix-list Upstream2-2 description IP Block Incoming
ip prefix-list Upstream2-2 seq 100 deny 0.0.0.0/0 le 32
!
ip prefix-list Upstream2-3 description IP Block Incoming
ip prefix-list Upstream2-3 seq 20 permit 192.168.0.0/24
ip prefix-list Upstream2-3 seq 30 permit 192.168.1.0/24
ip prefix-list Upstream2-3 seq 40 permit 192.168.2.0/24
ip prefix-list Upstream2-3 seq 50 permit 192.168.3.0/24
ip prefix-list Upstream2-3 seq 100 deny 0.0.0.0/0 le 32

route-map Upstream1 permit 10
match ip address prefix-list Upstream1 
set as-path prepend 65001
!
route-map Upstream1 permit 20
match ip address prefix-list Upstream1 -2
set as-path prepend 65001 65001
!
route-map Upstream1 permit 30
match ip address prefix-list Upstream1 -3
set as-path prepend 65001 65001 65001

!
route-map Upstream1 permit 40

route-map Upstream2 permit 10
match ip address prefix-list Upstream2 
set as-path prepend 65001
!
route-map Upstream2 permit 20
match ip address prefix-list Upstream2 -2
set as-path prepend 65001 65001
!
route-map Upstream2 permit 30
match ip address prefix-list Upstream2 -3
set as-path prepend 65001 65001 65001 
!
route-map Upstream2 permit 40
!

[Philip D'Ath]

It seems pointless, based on the information, to path-prepend both.

[Roel Reyes]

Anymore inputs? this is currently an ISP config

[Julio E. Moisa]

Hi

It does not make sense, the sequence 20 and 30 are not being used. it could be a misconfiguration. 

Also this line could be removed 

ip prefix-list Upstream1 seq 100 deny 0.0.0.0/0 le 32  as my understanding you are just matching some prefixes to assign the attribute.