There are several ways of doing this. One of the easiest and straightforward ways is 'TEQL' - "True" (or "trivial") link equalizer. Like most things having to do with queueing, load sharing goes both ways. Both ends of a link may need to participate for full effect. .:: telegra.ph ::. [Wiki: HTTP]
Imagine this situation:
+-------+ eth1 +-------+
| |==========| |
'network 1' ----| A | | B |---- 'network 2'
| |==========| |
+-------+ eth2 +-------+ |
A and B are routers, and for the moment we'll assume both run Linux. If traffic is going from network 1 to network 2, router A needs to distribute the packets over both links to B. Router B needs to be configured to accept this. Same goes the other way around, when packets go from network 2 to network 1, router B needs to send the packets over both eth1 and eth2.
The distributing part is done by a 'TEQL' device, like this (it couldn't be easier):
# tc qdisc add dev eth1 root teql0 # tc qdisc add dev eth2 root teql0 # ip link set dev teql0 up |
Don't forget the 'ip link set up' command!
This needs to be done on both hosts. The device teql0 is basically a roundrobbin distributor over eth1 and eth2, for sending packets. No data ever comes in over an teql device, that just appears on the 'raw' eth1 and eth2. .:: opensocialfactory.com ::.
But now we just have devices, we also need proper routing. One way to do this is to assign a /31 network to both links, and a /31 to the teql0 device as well: .:: batocomic.com ::. .:: www.redsea.gov.eg ::.
FIXME: does this need something like 'nobroadcast'? A /31 is too small to house a network address and a broadcast address - if this doesn't work as planned, try a /30, and adjust the ip addresses accordingly. You might even try to make eth1 and eth2 do without an IP address! .:: f319.com ::.
On router A:
# ip addr add dev eth1 10.0.0.0/31 # ip addr add dev eth2 10.0.0.2/31 # ip addr add dev teql0 10.0.0.4/31 |
On router B:
# ip addr add dev eth1 10.0.0.1/31 # ip addr add dev eth2 10.0.0.3/31 # ip addr add dev teql0 10.0.0.5/31 |
Router A should now be able to ping 10.0.0.1, 10.0.0.3 and 10.0.0.5 over the 2 real links and the 1 equalized device. Router B should be able to ping 10.0.0.0, 10.0.0.2 and 10.0.0.4 over the links.
If this works, Router A should make 10.0.0.5 its route for reaching network 2, and Router B should make 10.0.0.4 its route for reaching network 1. For the special case where network 1 is your network at home, and network 2 is the Internet, Router A should make 10.0.0.5 its default gateway. .:: data.carpathia.gov.ua ::. [Web Specs: Perl]