I have network with switches at access layer and 3 host networks, 2 core routers , 2 border routers , that have iBGP connection with each other and ospf with other 2 core routers, also each of them connected to 2 different ISP’s with eBGP. Border routers get only default routes from ISP’s. I want to split outbound traffic from access layer host networks between 2 ISP’s, for example 2 networks use 1st ISP connection and other 1 network uses 2nd ISP connection. If one connection fails , then all networks that use failed ISP will use another ISP. I want to know how to do it only with BGP , not PBR, ip sla …, only BGP.
BR3:
router ospf 1;
router-id 10.1.255.2;
redistribute bgp 200 subnets;
passive-interface Ethernet0/2;
default-information originate;
router bgp 200;
bgp router-id 10.1.255.2;
bgp log-neighbor-changes;
network 10.0.0.0 mask 255.255.255.0;
network 10.0.1.0 mask 255.255.255.0;
network 10.0.2.0 mask 255.255.255.0;
neighbor 10.1.255.1 remote-as 200;
neighbor 10.1.255.1 update-source Loopback0;
neighbor 10.1.255.1 next-hop-self;
neighbor 192.168.0.6 remote-as 101;
maximum-paths 4;
BR4:
router ospf 1;
router-id 10.1.255.1;
redistribute bgp 200 subnets;
passive-interface Ethernet0/1;
default-information originate;
router bgp 200;
bgp router-id 10.1.255.1;
bgp log-neighbor-changes;
network 10.0.0.0 mask 255.255.255.0;
network 10.0.1.0 mask 255.255.255.0;
network 10.0.2.0 mask 255.255.255.0;
neighbor 10.1.255.2 remote-as 200;
neighbor 10.1.255.2 update-source Loopback0;
neighbor 10.1.255.2 next-hop-self;
neighbor 192.168.0.2 remote-as 100;
maximum-paths 4;