LoadBalancing over tow ISP

[y.talibi]

I have a 3745 router with 2 2Mbps leased line from differents ISP. i have also some VPN connection on each leased line.

when i use 2 default static routes with 2 ISP, all VPN connection become down.

[naveen.venkatesh]

Hi,

You can do a policy based routing to handle the traffic between two different ISP's. You can have multiple default routes to the same ISP with multiple leased lines, but it will not work with different ISP's.

If you share the WAN connectivity information, based on that I can suggest the right configuration.

You have mentioned to have VPN connection, to which ISP address is your local VPN peer configured to,

Let me know the details,

thanks,

Naveen V

[y.talibi]

Hi,

I have VPN connection on both ISP, some clients connected with the ISP1 and the rest with ISP2.

When i use tow default route for tow serial line, i can share outgoing traffic between tow ISP not VPN connection, and incoming traffic come from one ISP.

Thanks,

Youssef Talibi

[2sbartholdi]

Hi Youssif

As Naveen pointed out you can't have two default routes this way. This is because the router will do load- sharing and therefore send some traffic to one ISP and some to the other.

That would not be too bad, but since you are connected with static routes I assume that you do have two public IP ranges (one from each supplier) and therefore you will send traffic from one ISP-net towards the other one.

Unfortunately most of the ISPs only allow traffic from one source and not from other ISP's networks in this constellation.

What you could do, though is to make policy- based routing as suggested:

VPN traffic -> use ISP1

All other traffic -> use ISP2

You'll have to ensure, though that all that traffic is coming in through the same ISP, though

hope that helps

Stephan

[y.talibi]

Hi Stephan,

I can't do this because my outgoing traffic exced 3Mpbs and i have only 2Mbps per link.

I want to load share only my outgoing traffic.

Incoming and VPN traffic will use only one ISP.

Thanks

[2sbartholdi]

Hi Youssif

Generally if you have tow providers which gave you one IP range each you must follow this rule:

- Traffic with IP address from provider 1 must leave through link of provider 1

- Traffic with IP address from provider 2 must leave through link of provider 2

What you need to do now is to find a good way to separate your traffic so that one portion of it is leavint / entering through ISP1 and the rest through ISP2.

Separation according to VPN and other traffic is one idea, you could add SMPT to the VPN side too.

If you really want to be able to use both lines without restriction, then you need to implement BGP and get an AS number.

Cheers

Stephan

[sushilk]

Hi,

Load sharing can not be achieved with 2 ISPs as 1st ISP will not allow the IP address of other ISP to flow though his network.

It ia not a configuration issue but it has somethign to do with the ISP policy.

The only solution is that a group of users have to use ISP1 and other grop has to use ISP 2 without any load sharing.

Regards

Sushil