4 way load balancing router

[choudharypranay]

Please suggest me a wired router that has 4 dedicated wan ports can can perform load balancing form 4 ISPs having different bandwidth.

[Georg Pauwen]

Hello,

are you running a routing protocol with the ISPs ? If you use static routes, you need to get creative. Let's say these are your 4 interfaces:

interface Serial0/0
ip address 172.16.1.1 255.255.255.252

interface Serial0/1
ip address 172.16.1.5 255.255.255.252

interface Serial0/2
ip address 172.16.1.9 255.255.255.252

interface Serial0/3
ip address 172.16.1.13 255.255.255.252

With 4 static default routes, CEF will by default perform equal cost per-destination load sharing:

ip route 0.0.0.0 0.0.0.0 Serial0/0
ip route 0.0.0.0 0.0.0.0 Serial0/1
ip route 0.0.0.0 0.0.0.0 Serial0/2
ip route 0.0.0.0 0.0.0.0 Serial0/3

Now, if you want more traffic to go over Serial0/1, you would need to add another static route pointing to the next hop of the interface:

ip route 0.0.0.0 0.0.0.0 172.16.1.6

Serial0/1 will now receive twice as much traffic as the other links. If you want even more traffic to go over this link, create a bogus host route pointing to the next hop, and then another default static route pointing to the bogus host:

ip route 10.1.1.1 255.255.255.255 172.16.1.6
ip route 0.0.0.0 0.0.0.0 10.1.1.1

Now Serial0/1 will receive three times as much traffic. You can play around with these static routes so it suits your needs...

I hope that makes sense...

[choudharypranay]

Thank you for your answer, but I guess my question was not clear enough.

I currently have CISCO RV082 router which has only 2 WAN ports. I was looking in Amazon for CISCO router with 4 WAN ports but did not find one. Can you suggest such a router that can support upto 500 devices?

[Georg Pauwen · Accepted solution]

Hello,

have a look at the 3925E or 3945E routers, both have 4 integrated WAN ports. They are quite expensive though...

[choudharypranay]

Yes... They are really costly! Any chance that there are other models close to$1000?

RV082 is just $100. What if I get three of them and load balance two of them using the third one!

[Georg Pauwen]

Easier yet, if you have three RV082s, just distribute your clients among those three. That wouldn't really be load balancing, but would have the same effect. You won't find any Cisco router with 4 WAN ports under $1000 I am afraid...

[choudharypranay]

Thank you. I will surely consider that if I'm able to route traffic between devices connected to different routers.

[Joseph W. Doherty]

If the RV082s support GLBP, you could load balance using that.  Either equally or proportionally to each ISP's bandwidth.

The ideal way to load balance would be to use PfR, but that's an upscale feature found on the ISRs.

[Joseph W. Doherty]

Or perhaps using, for the 3rd device, a L3 switch.

You did note you wanted to support 500 devices, and for that many devices, you probably should have multiple networks on your LAN side.  For that, you probably would want a L3 switch.

[Joseph W. Doherty]

BTW, the ISR 3Ks are either EoL or soon will be.  If you were to acquire a new ISR, you would want to look at the 4K series.

[Joseph W. Doherty]

With 4 static default routes, CEF will by default perform equal cost per-destination load sharing:

ip route 0.0.0.0 0.0.0.0 Serial0/0
ip route 0.0.0.0 0.0.0.0 Serial0/1
ip route 0.0.0.0 0.0.0.0 Serial0/2
ip route 0.0.0.0 0.0.0.0 Serial0/3

BTW, just be aware, using the interface for the next hop, especially for Internet destined traffic, often leads to the router's ARP cache using all the device's RAM.