Dual ISP connection and load balancing

[arivuram16]

We are having cisco 981f router and two isp connections. Both isp connections are connected in cisco router.  I would like configure the load balancing. Pl suggest and share the sample configuration.

WAN connections - 2 

LAN - One Ip segment

router model - cisco 981f

[Reza Sharifi]

You can configure 2 default routes (one to each ISP) and let the router load balance the traffic for you.

isp=1 ip route 0.0.0.0 0.0.0.0 <isp-1 ip gateway >

isp=2 ip route 0.0.0.0 0.0.0.0 <isp-2 ip gateway>

HTH

[arivuram16]

anyother configuration or thats all

[Richard Burts]

Before we can answer the question about whether any other config is needed we need to know more about your environment. You mention 2 isp connections. Is this connections to 2 different isp? Or 2 connections to same isp?

Especially if it is connection to 2 different isp then we need to know more about your IP address space. Do you have provider independent IP address? Or do you have IP addresses assigned by 1 isp? Or do you have IP addresses assigned by both isp?

We need to know if you are doing address translation for traffic going to the isp. The first suggestion assumes that you are not running any routing protocol with the isp. We need to know if this is the case or not.

When we know these things we will be able to give you better suggestions.

HTH

Rick

[arivuram16]

Hi, 

Thanks for your response. Below find the details as required.

ISP - 2 different ISP

ISP 1 WAN IP - 203.186.189.10/30

ISP 2 WAN IP - 202.88.153.30/30

LAN IP - 192.168.100.0/24 - Only private IP pool

Cisco router - 981F

Requirements - Would like use both ISP connections in load balancing mode. Right now no protocols running. 

Kindly advice for the above requirements and let me know if any other details required.

[Richard Burts]

Thank you for the additional information. I have another question. We can tell you how to configure for traffic from your network to the Internet and get responses. But is there anything in your network that needs to be accessible from the Internet? (does someone in the Internet need to be able to initiate traffic to something inside your network)

As was previously suggested you start by configuring two static default routes with the next hop being each ISP. Then you need to configure address translation. NAT on multiple interfaces is usually done with route maps to control the translation. Each route map will match to an interface and match an access list which permits traffic from your network (a standard access list is probably adequate - I am not aware of anything that would need an extended access list).

With two default routes and with NAT you should be load sharing with both ISP for hosts in your network. This is all that is required. There is something else that is optional and which you might want to consider. It deals with the potential issue of what if something happens to one of your ISP (or happens with your connection to the ISP). You could configure IP SLA and tracking for each of your default routes. With tracking if one of the ISP stops responding then that default route is withdrawn from the routing table and all of you Internet traffic will use the remaining ISP.

HTH

Rick