BGP prefix-list/route policy Config Help

[ap9025]

Team,
I need your help for BGP prefix-list/route policy Config.
We currently have a static route with the ISP for both the primary and secondary connection.
We are now going to make it BGP.
For simplicity, I have attached a photo of the basic connection to the ISP with the makeup number.
My ISP has shared their BGP configuration for both routers, including the prefix and route policy.
I am familiar with the interface and the basic BGP configuration. However, I am encountering difficulties in configuring the prefix-list/route policy on our router.
Our sole requirement is to have Router A as the primary path and Router B as the secondary path.
Would an expert be able to assist me, please?
I greatly appreciate your help.

################################################
ISP BGP Prefix list/ route-policy config on both their router
#################################################

prefix-set CUSTOMER-routes
10.10.10.0/24
end-set

route-policy to-CUSTOMER
if destination in default-route then
pass
endif
end-policy

route-policy from-CUSTOMER
if destination in CUSTOMER-routes then
set community (5.5.5.5:1000) #####>> not sure what is this 1000
endif
end-policy

#################################################
ISP BGP config on Router A
#################################################
router bgp 5555
neighbor 1.1.1.2
remote-as 6666
password [BGP PASSWORD]
address-family ipv4 unicast
route-policy from-CUSTOMER in
route-policy to-CUSTOMER out
default-originate

#################################################
ISP BGP config on Router B
#################################################
router bgp 5555
neighbor 2.2.2.2
remote-as 6666
password [BGP PASSWORD]
address-family ipv4 unicast
route-policy from-CUSTOMER in
route-policy to-CUSTOMER out
default-originate

-------------------------------------------------------------
Customer BGP Config Router A
-------------------------------------------------------------

router bgp 6666
network 10.10.10.0 255.255.255.0
neighbor 1.1.1.1 remote-as 5555
neighbor 1.1.1.1 password [BGP PASSWORD]
address-family ipv4
neighbor 1.1.1.1 activate

-------------------------------------------------------------
Customer BGP Config Router B
-------------------------------------------------------------

router bgp 6666
network 10.10.10.0 255.255.255.0
neighbor 2.2.2.1 remote-as 5555
neighbor 2.2.2.1 password [BGP PASSWORD]
address-family ipv4
neighbor 2.2.2.1 activate

-------------------------------------------------------------
Customer BGP Prefix list/ route-policy config on both their router
-------------------------------------------------------------
???
???
???

[paul driver]

Hello
Please see the attached example:

• Creation of IBGP peering between your local wan rtrs so they can share each others routing information
• Default local preference set for RTR-A to be preferred router for egress traffic
• As-path pre-pend on RTR-B to advertise local traffic via ISP-B to less preferred
• Bgp regular expression via a filter-list to negate your rtrs from become a transit path for the ISP

[ap9025]

Hello,

Really appreciate for config file. I have just got access of our Edge router on different site and management like to have similar config if possible. I understood few config but not sure about few lines.

I am thinking to duplicate same config with new IPs.

I have attached config of that site. Is it doable to just change IP in this config and make BGP working ? My concern is I dont have ISP config of that site so cant say whether ISP config really matter or not.

Again, thank you.

[Giuseppe Larosa]

Hello @ap9025 ,

>> set community (5.5.5.5:1000) #####>> not sure what is this 1000

it is a value chosen 5.5.5.5:1000 is a BGP standard community and the route-policy sets this value on the received prefix and accepts it if the prefix has a match on the prefix-set

route policies and prefix-sets should be IOS XR configuration elements are you sure the ISP devices are ASR 1000 that run IOS XE ?

Hope to help

Giuseppe

[paul driver]

Hello @Giuseppe Larosa 
my understanding here is that the XR is on the ISP PEs and the XE are the CE rtrs (hence the supplied cfg)

[ap9025]

Hello, 

Thank you for reply and information.

They said ASR 1000 in the past but not sure if they have replaced them recently.