1.  Field of the Invention
The field of the invention is data processing, or, more specifically, methods, apparatus, and products for optimizing communications throughput in a wireless networking environment that supports a plurality of communications channel topologies. 
2.  Description of Related Art
Increases in use of laptop computers within business enterprises and increases in worker mobility have fueled the demand for wireless networks.  In the past, wireless technology was a patchwork of incompatible systems from a variety of vendors.  The technology was slow, expensive, and reserved for mobile situations or hostile environments where cabling was impractical or impossible.  With the emergence of new industry standards and the deployment of lightweight wireless networking hardware across a broad market section, wireless technology has come of age. 
As new industry standards emerge in wireless technology, the wireless technology industry must embrace new capabilities, higher bandwidths, and new challenges.  The wireless technology industry is rapidly adopting these new standards and incorporating the standards into new products.  For example, the standard configuration of many wireless network laptop adapters implemented the Institute of Electrical and Electronics Engineers (‘IEEE’) 802.11b standard in 2003, the IEEE 802.11b and 802.11g standards in 2004, the IEEE 802.11a, 802.11b, and 802.11g standards in 2005, and soon many wireless network laptop adapters will implement the new IEEE 802.11n standard when the standard is finalized in 2007.  The group of the IEEE responsible for promulgating the 802.11n standard may choose the TGn Sync proposal supported by Intel and Philips.  Because the wireless technologies are backwardly compatible, implementation of the new standards by computer system manufacturers usually occurs in a somewhat straight forward manner.  That is, backwardly compatible in that wireless network laptop adapters implementing the industry standards fall back from implementing the IEEE 802.11n standard, to the IEEE 802.11a standard, to the IEEE 802.11g standard, and then to the IEEE 802.11b standard depending on conditions of a particular wireless networking environment. 
Wireless network adapters supporting the IEEE 802.11b, 802.11g, and 802.11n standards operate in the 2.4 gigahertz (GHz) radio frequency spectrum.  The number of channels available for data communications in the 2.4 GHz radio frequency spectrum depends on the mixture of the wireless network adapter population.  When the population consists of wireless network adapters implementing the IEEE 802.11b and 802.11g standards, three non-overlapping channels are available for data communications.  All three channels have a channel bandwidth of 20 megahertz (‘MHz’) as specified in the IEEE 802.11b and 802.11g standards.  When the population consists of wireless network adapters implementing the IEEE 802.11b and 802.11g standards and the 40 MHz channel option of the TGn Sync proposal for the IEEE 802.11n standard, two channels are available for data communications.  One channel has a bandwidth of 20 MHz for use by wireless network adapters implementing the IEEE 802.11b and 802.11g standards, and one channel has a bandwidth of 40 MHz for use by wireless network adapters implementing the TGn Sync proposal for the IEEE 802.11n standard. 
Dividing the 2.4 GHz radio frequency spectrum into three 20 MHz channels does not allow wireless network adapters supporting a 40 MHz channel bandwidth to utilize the highest data transfer rates specified in the TGn Sync proposal for the IEEE 802.11n standard.  In a communications channel topology that includes three 20 MHz channels, wireless network adapters supporting a 40 MHz channel bandwidth are forced to operate in their backward compatible modes that utilize a 20 MHz channel bandwidth.  Dividing the 2.4 GHz radio frequency spectrum into one 20 MHz channel and one 40 MHz channel, however, forces all the wireless network adapters that only support a 20 MHz channel bandwidth to transfer data through one 20 MHz channel.  Because an overwhelming majority of current wireless network adapters only support a 20 MHz channel bandwidth, data transfer rates in a communications channel topology that includes one 20 MHz channel and one 40 MHz channel would suffer greatly.  Regardless of whether a wireless network architect chooses a channel topology that includes three 20 MHz channels or a channel topology that includes one 20 MHz channel and one 40 MHz channel, the data transfer rates in a wireless networking environment suffer.