ACE 4710 Load balancing two ISPs

[gaboughanem]

Hi,

Does any one know how to load balance two/three ISPs using ACE.

What might be the default gateway?

Can i create a serverfarm with two rserver with different subnets?

Thank you and Regards,

George

[asharmav]

Hi George,

yes we can achieve the ISP loadbalencing with ACE,

VSERVER=0.0.0.0 (all IP traffic)

RSERVERS=routers

Probes to test “reliable addresses” on each ISP

Serverfarm with predictor roundrobin and transparent (it won’t do destination NAT)

Source NAT pool in each ISP VLAN

Above is the broad config to achieve this. There is no need to give the default gateway.

Regards

Abijith

[asharmav]

Yes, you can have the two rservers in different subnets.

Abijith

[gaboughanem]

Hi Abijith,

Thank you for your support, please can you exlpain what you meant by

[Probes to test “reliable addresses” on each ISP].

if possible provide a sample config on how to perform health monitoring on the ISP links although i am load balancing on

two routers where the ISP links are connected to.

Regards,

George

[asharmav]

Hi George,

Yes , you are correct you should load balance across two ISP routers, but assuming once of the ISP goes down, there is no way to know it, and ace keeps forwarding packet rather than redirecting all the connections to another isp.

To avoid this situation we use health monitoring, where in if the isp fails , then ace will remove the particular isp link from the list of available links to load balance. Hence we need to use a mechanism of probe to find the availability of the rotuers, you can have either icmp, tcp, snmp etc probing the isp routers for their availability

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/probe.html

The above is config guide for configuring probe wiht examples. Based on your requirement you can chose the type of probe you want to configure.

Hope this helps.

Regards

Abijith