BGP dual Homed on different local routers

[msaeedi]

dears 

have a good day 

i have the following scenario, i have three internet providers ISP with three Links terminated on three different local routers ( ISP 1 ---> R1 , ISP2 ----> R2, ISP3 -----> R3 ), each ISP think he is alone ISP, and each ISP manage one of the Local router ( ISP1 manage R1, ISP2 manage R2, ISP3 manage R3) so they configure normal static route pointing to Provider edge and they did simple PAT over single Public IP address given ( refer the attached diagram ).

the local routers connected to Firewall ( fortigate  FW ) , and FW is doing load balancing, but i need to configure BGP routing and do load balancing through WAN ?? 

how can i achieve like this scenario ?   kindly share your experience .., i need a response from guys who deploy like this scenario? 

Thanks & Regards 

[Deepak Kumar]

Hi,

AS you mentioned that currently, FortiGate firewall is handling the load balancing. This is the best solution. Keep in the mind that for normal internet connection ISP is providing only default route feature. If you want to configure the BGP then you have to contact with your ISP to get BGP ASN number, BGP routers, BGP authentication etc. And I hope for the normal connection ISP will not agree to provide all details. I am not sure but ISP will take charges of the same also.

Regards,

Deepak Kumar 

[Julio E. Moisa]

Hi

The following link could be useful, but you need to coordinate with the ISP's, they could use BGP and advertise a default route, take in consideration you must avoid your firewall is a transit device for BGP.

http://nullhaus.com/2014/02/fortigate-wan-load-balancing/

http://help.fortinet.com/fos50hlp/54/Content/FortiOS/fortigate-advanced-routing-54/Routing_BGP/Dual_Homed_Example.htm

:-)

[akbntc001]

From the title "BGP dual Homed on different local routers" I assume that you're running BGP between each Edge Router and the ISP (your scenario is actually a "Multi-homed BGP"). I don't think you can achieve any load-balancing trough the BGP attributes but it can be used for "Load Sharing".

The following Cisco document might be useful:

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html

Scroll down until you see this heading:

Load Sharing When Multihomed to Two ISPs Through Multiple Local Routers

HTH

Arjun