[wplug] loadbalancing over multiple network connections

[Joe Topjian]

>> Could someone suggest where I should be looking (or search terms for 
>> googling) to learn about the following?
>>
>> My company currently has a single ISP. We are considering getting 
>> network connectivity (mainly) for redundancy. I think it is fairly 
>> straightforward to configure such that network traffic is sent over 
>> eth1 instead of eth0 in the event of the connection to eth0 going > 
>> down.
>>
>> What I am interested in is using both connections all the time so 
>> that all hosts on my local network can benefit from the extra 
>> bandwidth as well as having a failover process so that when one 
>> connection fails all traffic is sent over the other. In case, it's 
>> not obvious I am referring primarily to traffic originating on the 
>> local network destined for the outside since there is little incoming 
>> traffic origniated externally.
>>
>> I started in tldp.org howtos and the nag, but I can't seem to get 
>> anywhere.
>> Any pointers, even to deadtree material, gratefully received.

> A google search (http://www.google.com/linux) turned up this article. 
> It looks to be what you're looking for, or a good start.
> This was my search criteria:
> using two ISPs multiple interfaces
>
> Here's the page:
> http://www.ussg.iu.edu/hypermail/linux/net/0107.3/0028.html

Another great source of info is in the Doc section of the kernel tree:
linux/Documentation/networking/bonding.txt

Also in that directory is ifenslave.c
Compile that and follow the instructions in the txt file and that 
should get you started.

I tried this with two interfaces connected to an office lan and it 
worked perfectly and easily. The default setting does load balancing 
and redundancy.. For example, ping a site, and you can see the lights 
on the NIC switch from one card to the other. Pull the cable from one 
NIC and the ping continues without any loss.

If you want to double your bandwidth by doing this, I think that takes 
a bit more work.. The mother of all info on this stuff can be found in 
the Advanced Linux Routing & Traffic Control:

http://lartc.org/

---
Joe Topjian
email: joe at portsys.net
web: http://zaven.us