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Load balancer

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July 10, 2010 8:59:10 AM

what is the primary function of a load balancer ?

More about : load balancer

July 11, 2010 4:29:23 AM

to balance the load? and typically act as a fail-over
July 11, 2010 10:39:25 AM

Kewlx25 said:
to balance the load? and typically act as a fail-over



wont it double the bandwidth to 4MBPS if each of the two broadband connection is of 2MBPS ?

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July 12, 2010 1:10:10 PM

Nope. The load balancer will only balance what is coming through it to keep other devices from getting over loaded.

If you have 2 servers behind a load balancer, each one will take 50% of the communications coming through. First, second, first, second.. if you had 4 streams coming in.

By doing this you will keep your bandwidth available since one device isn't handling all the load while the other does nothing.
July 12, 2010 2:07:17 PM

riser said:
Nope. The load balancer will only balance what is coming through it to keep other devices from getting over loaded.

If you have 2 servers behind a load balancer, each one will take 50% of the communications coming through. First, second, first, second.. if you had 4 streams coming in.

By doing this you will keep your bandwidth available since one device isn't handling all the load while the other does nothing.


ok so if i have one dsl line of 2048 kbps download speed and another back up dsl line from second service provider of 256 kbps

and i wish to use 2048 kbps as my main WAN and 256 kbps as my back up in case 2048 one fails, what will be the load balance sharing percentage to be entered in the above gui for each WAN ?

WAN 1 (2048kbps) = ____% how much

WAN 2 (256kbps) = ____% how much
July 12, 2010 3:27:11 PM

I wouldn't split it up like that. It doesn't make sense to do that.

You would want to set a low metric on WAN1 to use that. A slightly higher metric on WAN2. Say 1 and 20 respectively. If WAN1 fails, the next metric being 20, it would fail over to WAN2.

I don't know why you would want to load balance between the two. Why would you want to even use WAN2 unless WAN1 fails? You could though use WAN2 for other requests though. You would configure the load balancer to sent certain requests to WAN2 that you maybe don't want taking up bandwidth on WAN1.
July 13, 2010 7:02:08 AM

riser said:
I wouldn't split it up like that. It doesn't make sense to do that.

You would want to set a low metric on WAN1 to use that. A slightly higher metric on WAN2. Say 1 and 20 respectively. If WAN1 fails, the next metric being 20, it would fail over to WAN2.

I don't know why you would want to load balance between the two. Why would you want to even use WAN2 unless WAN1 fails? You could though use WAN2 for other requests though. You would configure the load balancer to sent certain requests to WAN2 that you maybe don't want taking up bandwidth on WAN1.

please give me the metric in percentage

shouldn't they both add up to 100 ? i mean WAN 1 and WAN 2

and you are correct i would use WAN 2 only if WAN 1 fails .........up till then i would like to use the full band width of WAN 1 which is 2MBPS.

how do i configure this above setting?
July 13, 2010 1:57:07 PM

You're not getting it. There is no percentage.

Load balancing shares a load. You don't want to share the load with your current set up. You want all traffic going through your fast connection. If that fails, you want all traffic going to your slow connection.

Load balancing is not needed here. You need to modify your routes.

Load balancing could be 50/50, 75/25, etc. That means 75% of the traffic will go through WAN1, 25% through WAN2. Depending on how much traffic you have, you could easily kill the slow connection.

Load balancing isn't really what you want. You need to modify you route statements to accomodate what you want to do. This is not something load balancing is going to help you with right now. If you have 2 connections at the same speed, load balancing would be a different story.
July 13, 2010 3:56:21 PM

riser said:
You're not getting it. There is no percentage.

Load balancing shares a load. You don't want to share the load with your current set up. You want all traffic going through your fast connection. If that fails, you want all traffic going to your slow connection.

Load balancing is not needed here. You need to modify your routes.

Load balancing could be 50/50, 75/25, etc. That means 75% of the traffic will go through WAN1, 25% through WAN2. Depending on how much traffic you have, you could easily kill the slow connection.

Load balancing isn't really what you want. You need to modify you route statements to accomodate what you want to do. This is not something load balancing is going to help you with right now. If you have 2 connections at the same speed, load balancing would be a different story.


ok that's interesting

so what i am looking for .....shall i call it "fail over" arrangement and not load balancing,

is that correct "fail over" ?

meaning that WAN 2 will only be used when WAN 1 disconnects or stops , is that correct ?
July 14, 2010 1:30:35 PM

Yes, you'll want to fail from WAN1 to WAN2. One way of doing this is designing a route with a metric. The route will take the shortest metric. 1 would be the first route, making it 2 would make it a second route, but generally you step it up a little to 20, or 50, or 100, just to make sure it doesn't keep failing over unnecessarily.
July 14, 2010 1:52:58 PM

riser said:
Yes, you'll want to fail from WAN1 to WAN2. One way of doing this is designing a route with a metric. The route will take the shortest metric. 1 would be the first route, making it 2 would make it a second route, but generally you step it up a little to 20, or 50, or 100, just to make sure it doesn't keep failing over unnecessarily.

ok , so if you can see the pic of the load balancer gui in my previous post what will you fill in the WAN 1 and WAN 2 percentage filelds, going by what you have advised?
July 14, 2010 5:56:08 PM

I wouldn't even route it through the load balancer.

At a switch or router level I would set the routes and put the metric in there. The load balancer is almost worthless for the scenario being discussed.
July 15, 2010 5:53:37 AM

riser said:
I wouldn't even route it through the load balancer.

At a switch or router level I would set the routes and put the metric in there. The load balancer is almost worthless for the scenario being discussed.

so i should just leave the load balancer page in the gui completely empty :o 

so that implies that i need only fail over settings , is that correct ?
July 15, 2010 1:30:26 PM

Yes. The only time you would want to load balance a WAN connection is when you have two WAN connections of the same speed.
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