Point 1- Currently we have 1 ISP which is terminated on Router 2951 and now we are planning to add 1 more Router 2951 and 2nd ISP link. Need to achieve Failover and load balancing between these TWO Router, please suggest how can i achieve this.

Point 2 - Also if possible - can redirect FTP Traffic to Separate link.


We have 2 Router 2951, both having 50mbps Link terminated on each router. Achievement - we have to do equal load balancing,at a time both wan link should be used and WAN Link Failover, Example - At a time both link should be used and if 1 link fails the other link should take over, i.e. all traffic will pass through ISP 2 if ISP 1 fails.

this we want to achieve with IP SLA on 3750x switch Attached is the network diagram for reference.

enter image description here

  • Diagram and configs would greatly improve your chances of getting an answer... also other ideas for improvement May 6, 2014 at 10:38
  • HI mike, waiting for you reply...
    – Spei043
    Jun 4, 2014 at 9:20
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 8, 2017 at 21:01

2 Answers 2


Are you running BGP with ISPs? Or just defaults towards Internet?

You should propably configure HSRP on the internal side between routers to have single default gateway for your network - or multiple default gateways if the inside will be segmented in VLANs.

If you're running BGP and you do have PI space, announce it on both links, then try to tune using the BGP traffic engineering features.

If you don't have BGP, you can try to use Performance Routing coupled with NAT, because you'll need to match outgoing traffic with properly selected source IP addresses (your ISPs should do uRPF and check what source addresses you're using on links they provide you).

As Mike stated, topology drawing would benefit the discussion.

  • OK i will upload the diagram.. please see the below link. dropbox.com/s/2e83ixxlq2nr08w/cap.JPG - there is no BGP in the network its just defaults towards internet
    – Spei043
    May 9, 2014 at 5:32
  • HI any reply,....please have a look
    – Spei043
    Jun 4, 2014 at 9:19
  • HI , let me know how can i achieve this vis PBR/IP SLA.
    – Spei043
    Jun 16, 2014 at 11:11
  • @Spei043, it would help if you actually gave us configurations from your existing routers. This site is here to help as much as possible; however, it's not really a "work outsourcing" site, which seems to be the approach you're taking so far. If you could show some effort yourself in implementing the functionality, you may find that our responses are proportionately more precise in achieving your needs. Jun 16, 2014 at 11:40
  • I have some config - can i place this config to L3 switch
    – Spei043
    Jun 19, 2014 at 11:27

Here's a few ideas

Inbound Load Balancing:

  • Via BGP (If you have your own AS): announce on both link, as @Lukasz said, but won't be able to force FTP traffic to a specific link.
  • No BGP (No public AS, two different Public IPs - once per ISP): DNS load balancing - have your DNS give out each IPs to requests, on a round robin basis. You can have a specific hostname for your FTP server that points to the desired link

For Outgoing connections:

Have your L3 switch do routing load balancing (not exclusive to BGP) by having two routes to the internet announced by your two ISP routers:

If the router receives and installs multiple paths with the same administrative distance and cost to a destination, load-balancing can occur.

(http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/5212-46.html )

Then you control the announcement by your ISRs to your L3 switch with IP SLA Monitor on the 2951 to track some public IPs and modify the announced route, so that if one cannot reach the Internet (router/link is UP but ISP has routing problems) you'll stop advertising internally the bad link.


For your FTP, you can use Policy Based Routing on your L3 switch to bypass routing and force FTP traffic to use all outgoing FTP traffic on a single link


If you're ever looking for a hardware solution that does pretty much all this, take a look at Radware's Linkproofs, at least id did a few years ago.

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