Help me in Redundancy and load balancing Please

Unanswered Question
Jan 18th, 2010

Dear All,

I am new in this group, I need some help from Cisco Expert Friends. I Just need scenario to configure Redundancy and Load Balancing between two ISP. My Present Network Daigrame.

1. Two Router with 3 No's of Interfaces (1WAN, 2LAN). Each Router have 3 Interface. (1 For Wan, 2&3 For CoreSwitches)

2. Two Core Switches with redundancy using Cascading Cable.

So i need to make Redundancy and Load Balancing using this scenerio.

Please Help in this scenerio to:

--What Protocol i have to used for redundancy and load balancing.

--Its better to send any link so i can read and implement.

Please do needful help as soon as possible.

I have this problem too.
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Arup Dutta Mon, 01/18/2010 - 23:42


    you don't mention here how is your connectivity type!If it same ISP you can use metrix against the preffered route.

Mohamed Sobair Tue, 01/19/2010 - 00:24


Do you have your own IP block Public subnet? or you just have IP subnets from both ISPs.


If you have your own IP subnet, then loadbalancing & redundancy could be achieved, you would need to have HSRP or GLBP on the Core facing Interface with routers and run IBGP between both routers. refer to Loadsharing with BGP (Multihoming Section).

The connectivity between both routers will also introduce redundancy if one of the WAN fails in order to reroute the traffic through anothr ISP. you could also have static routes instead of BGP, but typically in such design , the best approach is to have BGP with the ISPs and IBGP between both routers.

If Static routes in place, then normal tracking route SLA to the ISP and If fails, Secondary default takes place to the next router.

On the LAN , you could have GLBP or Multiple HSRP groups pointing to differnet GWs, so that the hosts inside points to differnt HSRP Active group at a time.

Scenario 2:

If you dont have PUblic IP subnet, then loadbalncing cant be achieved, the only way is to have redundancy and nat configuration on the routers with the same previous setup on the LAN.

Keep in mind , If you have servers inside , this setup is also require additional attention, as you cant have servers using different IP pools connecting to the Internet.




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