Dual internet connection with 2 ISP as active/active

[kamlesh yadav]

Dear All,

i have one router with 2 ISP connected on that. from both ISP, router is receiving default route.

There is one firewall between LAN and internet router and default route pointing towards ISP1.

topology is attached for your reference.

Below are the challenges which i am facing,

1. for one particular subnet, traffic should be routed through ISP2.
2. How can perform routing for that subnet on firewall?
3.How can perform routing for that subnet on internet router. Internet router has default route from ISP1 in routing table,

Need your expertise on this...

[Reza Sharifi]

Hi,

Since you are running in active/active with 2 default routes from both providers the traffic will be load balanced to both providers.  If you want to send a particular subnet to ISP2 only than you need PBR on the Internet router.

Here is a link with example:

http://www.cisco.com/c/en/us/support/docs/ip/ip-routed-protocols/47121-pbr-cmds-ce.html

HTH

[kamlesh yadav]

Thanks Reza for prompt response.

I have only one default route from ISP1 in my routing table. How can i install default route from ISP2 as well?

iNTERNET#sh ip bgp
BGP table version is 5, local router ID is 115.12.12.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*  0.0.0.0          15.12.12.2               0             0 15 i
*>                  13.12.12.2               0             0 13 i

and on firewall,how can i add two static default route pointing towards two different interface?

[Reza Sharifi]

Hi,

You just define a default route and point to the next hop IP address (ISP2).  It will look the same as the other one you already have.  It is just pointing to a different provider.

Can you clarify a couple of questions:

1-The ISPs have given you 2 /24 subnets right? if that is the case are you using the same segments between your Internet router and the service providers routers.  Usually the service providers give a /30 and you use that to peer with them, but according to your output you are using the same public IP they gave you.

2-If this is the case than how can you assign the same IP segment to 2 different interfaces on the Internet router, as according to your diagram 13.12.12.0/24 and 115.12.12.0/24 both extend to the firewall.

HTH