Channel bonding

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Channel bonding (also known as "Ethernet bonding") is a computer networking arrangement in which two or more network interfaces on a host computer are combined for redundancy or increased throughput.

On Ethernet interfaces, channel bonding requires assistance from both the Ethernet switch and the host computer's operating system, which must "stripe" the delivery of frames across the network interfaces in the same manner that I/O is striped across disks in a RAID array. For this reason, channel bonding is sometimes also called RAIN, or "redundant array of independent network interfaces". See also EtherChannel and 802.3ad (link aggregation).

Multiple dial-up links over POTS can be channel-bonded together in the same manner and can come closer to achieving their aggregate bandwidth than routing schemes which simply load-balance outgoing network connections over the links. This is known as modem bonding.

Similarly, multiple DSL lines can be bonded to give higher bandwidth; in the United Kingdom, ADSL is sometimes bonded to give for example 512kbit/s upload bandwidth and 4 megabit/s download bandwidth, in areas that only have access to 2 megabit/s bandwidth.

On 802.11 (Wi-Fi) channel bonding is used in "Super G" technology, also referred as 108Mbit/s. It bonds two channels of classic 802.11g, which has 54Mbit/s signaling rate. On IEEE 802.11n, Channel Bonding, also known as 40 MHz, is a second technology incorporated into 802.11n which can simultaneously use two separate non-overlapping channels to transmit data. Channel bonding increases the amount of data that can be transmitted. 40 MHz mode of operation uses 2 adjacent 20 MHz bands. This allows direct doubling of the PHY data rate from a single 20 MHz channel. (Note however that the MAC and user level throughput will not double.)

See also

• Inverse multiplexing
• Link aggregation

References

• IEEE 802.3ad Link Aggregration Task Force