HowtoMatrix

An easy, inexpensive way to double up Ethernet interfaces to get more more bandwidth and reliability is called Ethernet bonding.
While Gigabit Ethernet is all exciting and the hot new fad, you can get
a lot of mileage out of using Ethernet bonding to give your existing
gear a nice boost without spending much extra money. Just stuff two
ordinary 10/100 Ethernet interfaces into a machine, tweak a few
configuration files, and you’re in business. If one fails you won’t
lose connectivity. It is a good cheap upgrade for your servers–you’ll
have several options for configuring load balancing and failover, and
with the right gear you’ll get an instant bandwidth boost by combining
the bandwidth of the two interfaces.

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