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New Member

Load Balancing between two cisco router

Hello Friends,

Please advise me,We are using two Cisco Routers with F5 Load balancer,

Router A (Cisco 2811) has one ISP configured

Router B (Cisco 3825) has the other ISP configured

ISP on Router A has 5 Mbps Bandwidth

ISP on Router B has 10 Mbps Bandwidth

My Doubt is if one of the link is down,F5 is load balanced but the packet is go to both downed and working interface( Fast ethernet or Gigabit ethernet) it becomes slow down the internet.How to stop the packet travel to downed ISP router ?

Additional information

We are using a Default routing protocol (ip route other wan intf ip )

F5 load balancer model F5 BIG IP

Here i have attached my N/w diagram for ur reference..........

Can someone solve my question.............please

Thank you.

  • Network Management
New Member

Load Balancing between two cisco router

Unfortunately, I don't know much about the F5 load balancer, but I can provide a temporary cisco style solution. You could just use a backup default route. If I understand correctly your situation is something like the below diagram

That being the case, let's assume that router B is the top one connected to ISP 1 and the bottom left one is router A connected to ISP 2. Your primary connection is between the router labeled client router and ISP1. However let's say that the network goes down for whatever reason. You could simply add the following line to router B

ip route 200

That last number is the important one - it's the administrative distance. Setting it to a high value like 200 will cause it to only be used if your standard default route is down.


New Member

Load Balancing between two cisco router

Hello Mohammed,

A floating default as Grant described can be useful if both links are terminating on a single router. If however, your redudant links are terminating on different routers then it would make sense to run a redundancy protocol between the two routers like HSRP or VRRP and then track the status of the WAN interfaces. You would then point the default route on the F5 to the virtual HSRP/VRRP address.