BGP as-path prepend for specific destination

[mirage]

Dear all,

I have a following topology in my lab:

R1 (as 208097) -- > R2 ISP (as16010)  -- R3 (as 35805)

                                                |

                                      R4 (as 10101)

I want to

prepend

my announce for AS35805 only with

as-path access-list

and

route-map

like this:

R1

interface FastEthernet0/0
ip address 2.2.2.1 netmask 255.255.255.252
duplex auto
speed auto

router bgp 20809
no synchronization
bgp router-id 1.1.1.254
bgp log-neighbor-changes
network 1.1.1.0 netmask 255.255.255.0
neighbor 2.2.2.2 remote-as 16010
neighbor 2.2.2.2 route-map BGP_OUT_RMAP out

ip as-path access-list 50 permit ^20809 16010 35805$
ip as-path access-list 50 deny .*

ip prefix-list MM seq 10 permit 1.1.1.0/24

route-map BGP_OUT_RMAP permit 10

match ip address prefix-list MM
match as-path 50
set as-path prepend 20809 20809

But it doesn't work

Does it possible?

[Edson A. Hernandez]

The

as-path

filter list should be

ip as-path access-list 50 permit ^$
ip as-path access-list 50 deny .*

[MHM Cisco World]

NO it not possible.
if the AS20809 is origin of prefix then the

as-path

is it

AS-path

only no more

 ^$

what you can do in using same but in 35805 and here also you need from R2 (in your topology) send multipath hence the AS35805 can use as-prepend IN direction 

[mirage]

R2 is an ISP (in real life), so I unable to change anythig there.

Is there any way to solve my issue?

I want to accept incomming traffic from AS16010, and for any other AS after AS 16010 make this path as backup..

[MHM Cisco World]

sorry your in your topology can point each AS for each router 
and which router you want to configure primary and backup R1 I think 
thanks 

[mirage]

So, it is not possible in this topology, correct?

[MHM Cisco World]

You dont answer me, 
R1 you want to use primary and backup ?

[MHM Cisco World]

check below

[mirage]

No,

This device is backup BGP link. But hase an direct access for AS16010. I want to use it only for them (as16010) when another device (not in topology) is active.

[MHM Cisco World]

I see you edit the post
just want to mention which one need primary and backup 

[MHM Cisco World]

[mirage]

Please, check full topology image.

R5 is a primary router, connected to primary isp. R1 is Backup router, connected to backup isp.

I want to load-balance incomming traffic as follows:

Incomming traffic from AS 35805 and 10101 to  AS 20809 need to receive via AS 34797,  and traffic from AS 16010 ONLY to AS20809 via R1.

For outgoing traffic all is done via local preferene and

as-path access-list

, but my trouble is inbound traffic.

[MHM Cisco World]

if there is bgp between AS35805/AS10101 and primary ISP AS then it easy 

[mirage]

Yes, these AS have BGP connection between

[MHM Cisco World]

then I will share the solution tonight 
MHM