BGP with two ISP | Inbound traffic control

[florinmarian]

Hello again!
In short, I have two BGP sessions with two different ISPs, as follows:
AS8708: 150Mbps guaranteed and 1Gbps best-effort metropolitan (only IP addresses from their network)
AS8953: 500Mbps guaranteed, without best effort

What I want:
- To have an egress bandwidth of at least 500Mbps to the default route (ideally it would be 650Mbps, but I have no idea if this is possible)
- To have an incoming bandwidth of at least 500Mbps

Currently, the egress traffic goes preferentially through AS8953 and it's OK, I don't reach more than 500Mbps, but I don't care about that, on the other hand, on the ingress side, the ISP with 150Mbps has shorter routes and most of the external traffic arrives at speeds below 150Mbps, using only the ISP with AS8708.
If I disable AS8708, I have 500Mbps in/out, but I still want to use both ISPs to balance the traffic where possible and as redundancy if somehow the connection with AS8953 dies.

Thank you!

Current config:

ip prefix-list ALLOWED-PREFIXES-IPv4 seq 10 permit ABC.DEF.240.0/24
ip prefix-list ALLOWED-PREFIXES-IPv4 seq 20 permit ABC.DEF.241.0/24
!
ipv6 prefix-list ALLOWED-PREFIXES-IPv6 seq 10 permit XXXX:8f02:f04f::/48
ipv6 prefix-list ALLOWED-PREFIXES-IPv6 seq 20 permit XXXX:8f02:f04f::1/128
!
route-map ISP1-BGP-ROUTE-MAP permit 10
 set weight 16384
 set local-preference 100
 set metric 100
 set as-path prepend 57403 57403 57403 57403 57403
!
route-map ISP2-BGP-ROUTE-MAP permit 10
 set weight 32767
 set local-preference 200
 set metric 100
!
router bgp 57403
bgp dmzlink-bw
bgp router-id 10.192.63.19
no bgp default ipv4-unicast
bgp fast-external-fallover
bgp log-neighbor-changes
bgp graceful-restart restart-time 120
bgp graceful-restart stalepath-time 360
bgp graceful-restart
bgp bestpath as-path multipath-relax
maximum-paths 2
maximum-paths ibgp 2
neighbor 10.192.63.17 remote-as 8708
neighbor 10.192.63.18 remote-as 8708
neighbor 92.180.51.73 remote-as 8953
neighbor 2a02:2f08:fff::1 remote-as 8708
neighbor 2a02:2f08:fff::2 remote-as 8708
neighbor 2a02:a58:4009:2::1 remote-as 8953
!
address-family ipv4
 neighbor 10.192.63.17 activate
 neighbor 10.192.63.18 activate
 neighbor 92.180.51.73 activate
 neighbor 10.192.63.17 dmzlink-bw
 neighbor 10.192.63.18 dmzlink-bw
 neighbor 92.180.51.73 dmzlink-bw
 neighbor 10.192.63.17 next-hop-self
 neighbor 10.192.63.18 next-hop-self
 neighbor 92.180.51.73 next-hop-self
 neighbor 10.192.63.17 route-map ISP1-BGP-ROUTE-MAP in
 neighbor 10.192.63.18 route-map ISP1-BGP-ROUTE-MAP in
 neighbor 92.180.51.73 route-map ISP2-BGP-ROUTE-MAP in
 neighbor 10.192.63.17 send-community both
 neighbor 10.192.63.18 send-community both
 neighbor 92.180.51.73 send-community both
 neighbor 10.192.63.17 maximum-prefix 20000
 neighbor 10.192.63.18 maximum-prefix 20000
 neighbor 92.180.51.73 maximum-prefix 20000
 neighbor 10.192.63.17 prefix-list ALLOWED-PREFIXES-IPv4 out
 neighbor 10.192.63.18 prefix-list ALLOWED-PREFIXES-IPv4 out
 neighbor 92.180.51.73 prefix-list ALLOWED-PREFIXES-IPv4 out
 no neighbor 2a02:2f08:fff::1 activate
 no neighbor 2a02:2f08:fff::2 activate
 no neighbor 2a02:a58:4009:2::1 activate
 no auto-summary
 no synchronization
 network ABC.DEF.240.0 mask 255.255.255.0
 network ABC.DEF.241.0 mask 255.255.255.0
exit-address-family
!
address-family ipv6
 neighbor 2a02:2f08:fff::1 activate
 neighbor 2a02:2f08:fff::2 activate
 neighbor 2a02:a58:4009:2::1 activate
 neighbor 2a02:2f08:fff::1 dmzlink-bw
 neighbor 2a02:2f08:fff::2 dmzlink-bw
 neighbor 2a02:a58:4009:2::1 dmzlink-bw
 neighbor 2a02:2f08:fff::1 next-hop-self
 neighbor 2a02:2f08:fff::2 next-hop-self
 neighbor 2a02:a58:4009:2::1 next-hop-self
 neighbor 2a02:2f08:fff::1 send-community both
 neighbor 2a02:2f08:fff::2 send-community both
 neighbor 2a02:a58:4009:2::1 send-community both
 neighbor 2a02:2f08:fff::1 maximum-prefix 20000
 neighbor 2a02:2f08:fff::2 maximum-prefix 20000
 neighbor 2a02:a58:4009:2::1 maximum-prefix 20000
 neighbor 2a02:2f08:fff::1 prefix-list ALLOWED-PREFIXES-IPv6 out
 neighbor 2a02:2f08:fff::2 prefix-list ALLOWED-PREFIXES-IPv6 out
 neighbor 2a02:a58:4009:2::1 prefix-list ALLOWED-PREFIXES-IPv6 out
 no synchronization
 network XXXX:8f02:f04f::/48
 network XXXX:8f02:f04f::1/128
 exit-address-family
!

[Flavio Miranda]

Hi @florinmarian 

 Use AS prepend on the neighbor with  AS8708

[florinmarian]

Thanks for your answer!

As you can see in the commands above, I did this but after 8 hours of adding that prepend, nothing has changed.

Switch#show ip bgp
BGP table version is 16668, local router ID is 10.192.63.19
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *   0.0.0.0          10.192.63.18           100    100  16384 57403 57403 57403 57403 57403 8708 i
 *                    10.192.63.17           100    100  16384 57403 57403 57403 57403 57403 8708 i
 *>                   92.180.51.73           100    200  32767 8953 i

[Flavio Miranda · Accepted solution]

You should prepend your own AS.

route-map ISP1-BGP-ROUTE-MAP permit 10
set weight 16384
set local-preference 100
set metric 100
set as-path prepend 8708 8708 8708 8708  8708

And the direction is out.

neighbor 10.192.63.17 route-map ISP1-BGP-ROUTE-MAP out
neighbor 10.192.63.18 route-map ISP1-BGP-ROUTE-MAP out