Hi,
i have a router which is connected to two isp. ISP1 and ISP2. we are running bgp with both of them. for inbound traffic we are receiving the traffic almost as expected but for outbound traffic all the traffic is following ISP1 always. and we do not wanted like that and need to send traffic to ISP1 and some to ISP2 (both ISP are sending default route through BGP). after doing many changes we did not get desired results so i went with other solution.
! Step 1
! Define SLA to track the default route and set default route according to availability.
! SLA for ISP1 as default Gateway
ip sla 15
icmp-echo 172.16.180.161
! ISP1 Side IP
frequency 5
ip sla schedule 15 life forever start-time now
!!!!!! Track for SLA 15 to check the status of next hop ISP1
track 15 ip sla 15 reachability
delay down 120 up 1
! Default route for all traffic is ISP1 with default metrics. and Track the availability of ISP1.
ip route 0.0.0.0 0.0.0.0 172.16.180.161 track 15
! Default route for all traffic to ISP2 with metric 15 set lower then 20 (EBGP)
! ISP2 side 172.17.4.137
ip route 0.0.0.0 0.0.0.0 172.17.4.137 15
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! For Load balancing create route-map and call the ACL for preferred path.
! ACL to match the subnet we need to prefer to ISP1.
!
access-list 80 permit 192.12.176.0 0.0.0.255
access-list 81 permit 192.12.177.0 0.0.0.255
! ACL to match the subnet we need to prefer to ISP2.
access-list 82 permit 192.12.178.0 0.0.0.255
access-list 83 permit 192.12.179.0 0.0.0.255
!!!!! IP SLA for main ISP1 and backup ISP2
ip sla 16
icmp-echo 172.16.180.161
frequency 5
ip sla schedule 16 life forever start-time now
!!!!!! Track for IP SLA 16 for making the next hop for preferred subnet to ISP1
track 16 ip sla 16 reachability
delay down 120 up 1
!!!!! IP SLA for main ISP1 and backup ISP2
ip sla 17
icmp-echo 172.17.4.137
frequency 5
ip sla schedule 17 life forever start-time now
!!!!!! Track for IP SLA 16 for making the next hop for preferred subnet to ISP1
track 17 ip sla 17 reachability
delay down 120 up 1
!!!! Route map to set ISP1 as main and ISP2 as backup for subnet 80 and 81
route-map MAIN_ISP1_BACK_ISP2 permit 10
match ip address 80 81
set ip next-hop verify-availability 172.16.180.161 16 track 16
!!!! Route map to set ISP2 as main and ISP1 as backup for subnet 82 and 83
route-map MAIN_ISP2_BACK_ISP1 permit 10
match ip address 82 83
set ip next-hop verify-availability 172.17.4.137 17 track 17
int Loopback 100
ip address 192.12.176.1 255.255.255.255
ip policy route-map MAIN_ISP1_BACK_ISP2
int Loopback 101
ip address 192.12.177.1 255.255.255.255
ip policy route-map MAIN_ISP1_BACK_ISP2
Int Loopback 200
ip address 192.12.178.1 255.255.255.255
ip policy route-map MAIN_ISP2_BACK_ISP1
int Loopback 201
ip address 192.12.179.1 255.255.255.255
ip policy route-map MAIN_ISP2_BACK_ISP1
After doing this still the traceroute source as any of these loopback is following ISP1 which we do not want.
so kindly let me know where i am making mistake
Thanks
