BGP Advertisement

[Norman123]

Hello,

I need some help with the following BGP configuration

router bgp 300

neighbor 192.169.10.1 remote-as 200

neighbor 192.169.10.1 description ISP-A

neighbor 192.169.20.1 remote-as 400

neighbor 192.169.20.1 description ISP-B

!

address-family ipv4

network 10.0.0.0 mask 255.255.255.0

network 20.0.0.0 mask 255.255.255.0

network 30.0.0.0 mask 255.255.255.0

network 40.0.0.0 mask 255.255.255.0

neighbor 192.169.20.1 activate

neighbor 192.169.20.1 next-hop-self

neighbor 192.169.20.1 soft-reconfiguration inbound

neighbor 192.169.20.1 prefix-list ISPBIn in

neighbor 192.169.20.1 route-map ISPBOut out

neighbor 192.169.10.1 activate

neighbor 192.169.10.1 next-hop-self

neighbor 192.169.10.1 weight 500

neighbor 192.169.10.1 soft-reconfiguration inbound

neighbor 192.169.10.1 route-map ISPAOut out

maximum-paths 4

exit-address-family

!

ip prefix-list ISPBIn seq 10 permit 0.0.0.0/0

ip prefix-list ISPBIn seq 100 deny 0.0.0.0/0 le 32

route-map ISPBOut permit 20

match ip address prefix-list ISPBPrimary

set origin incomplete

!

route-map ISPBOut permit 30

match ip address prefix-list ISPBBackup

set origin incomplete

set as-path prepend 300 300 300 300

route-map ISPAOut permit 10

match ip address prefix-list ISPAPrimary

set origin incomplete

route-map ISPAOut permit 20

match ip address prefix-list ISPABackup

set origin incomplete

set as-path prepend 300 300 300 300

ip prefix-list ISPBPrimary seq 20 permit 20.0.0.0/24

ip prefix-list ISPBPrimary seq 30 permit 30.0.0.0/24

ip prefix-list ISPBPrimary seq 40 permit 40.0.0.0/24

ip prefix-list ISPBPrimary seq 100 deny 0.0.0.0/0 le 32

ip prefix-list ISPBBackup seq 50 permit 10.0.0.0/24

ip prefix-list ISPBBackup seq 100 deny 0.0.0.0/0 le 32

ip prefix-list ISPAPrimary seq 5 permit 10.0.0.0/24

ip prefix-list ISPAPrimary seq 100 deny 0.0.0.0/0 le 32

ip prefix-list ISPABackup seq 8 permit 20.0.0.0/24

ip prefix-list ISPABackup seq 9 permit 30.0.0.0/24

ip prefix-list ISPABackup seq 10 permit 40.0.0.0/24

ip prefix-list ISPABackup seq 100 deny 0.0.0.0/0 le 32

______________________________________________

Want to achieve multiple of things

1- block 10.0.0.0/24 to be routed on ISP-A as primary and the rest 3 blocks on ISP-B if the two paths are up

2- if one of the path is down all blocks should be working on the active path

My configuration is not matching, there is asymmetric traffic .

[MHM Cisco World]

Check my old comment to your old post' 

You need pbr because pbr is only that check source of packet and forwarding it to correct ISP.

MHM

[Norman123]

Dear MHM 

I try your solution, it only affect the outbound traffic .

[MHM Cisco World]

The Inbound is control via AS prepend 

And Outbound since yoh receive defualt route from both ISP is control by pbr 

And hence no asymmetric routing.

I dont have time now to share lab but my suggestion is sure work

Goodluck 

MHM

[Norman123]

Dear MHM,

If you have later on time to share small lab, it will be appreciated.

So I can understand well how it will work and test it

Thank you for your time

[paul driver]

---

---

Hello

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@MHM Cisco World wrote:

And Outbound since yoh receive defualt route from both ISP is control by pbr 

---

Why PBR?, You can control egress traffic using a local bgp weight attribute towards each ebgp peer

[paul driver]

Hello
You BGP cfg looks quite convoluted to what i understand you want to achieve , which is

Ingress from ISP perspective- 
 10.0.0.0/24 via ISPA
  all other via ISPB  

Egress from AS300 perspective- 
prefer via ISPA for 10.0.0.0/24 users
all other local traffic via ISPB
 
see attached file for possible solution.

[Norman123]

hello paul,

Your config didn't match what is needed 100%