ISP LOAD BALANCING

[Soumik Mondal]

Dear All

As per our client wants to implement load balancer .Now during planning phase I find a challenge.I have given a basic diagram for the same.From router -1 to primary load balancer is fine.But I need a connection to secondary  load balancer also in case of primary load balancer fails.How I configure this interface in Router-1???Can any body help me regarding that.Please let me know if you need any feedback from my side...

[Jan Hrnko]

Hi,

basically, you just need to add them both to routing and make one of the routes more preferred(better). Do you use static routing or dynamic routing protocols like EIGRP or OSPF?

If you use static routing, you can implement floating static routes. You would create ip route from R1-LB1 with AD of 1 and R1-LB2 with AD of 254 for instance. That way, if LB1 fails, R1 will install the static route to LB2 into its routing table...

If you leverage on dynamic routing protocols, you should make one route more preferred over the other. You can achieve this by changing the link parameters. In EIGRP it would be delay - link R1-LB2 should have higher delay parameter than R1-LB1 for instance thus making it more preferred. When using OSPF you can change the cost of the link.

R2 should be configured analogically.

Best regards,

Jan

[Alcides Miguel]

Hi Soumik,

Is router 1 interface and load balancer 1/2 in the same subnet? is the loadbalancer part of one cluster?

if all traffic coming from internet is forwarded to the loadbalancer I should go with an icmp sla tracking the loadbalencer states if load balancer 1 goes down then route to that should be removed from routing table and traffic should be forwarded to the second loadbalancer via a static route.

best regards,

Alcides

[Soumik Mondal]

Dear All

Thanks for your reply.My question is how I shall assign IP in router interface.Because for each router there is one active interface that will connect to active load balancer(LB-1).Each router will have a connection to secondary LB(LB-2) which will work only if primary LB fails.How I shall achieve this .