BlueSky: a cordless networking solution for palmtop computers |
| Pravin Bhagwat, Chatschik Bisdikian, Ibrahim Korpeoglu, Mahmoud
Naghshineh, Satish Tripathi
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| Paltmtop computers are rapidly becoming the popular platform of choice
for running personal productivity applications, but their networking capabilities
are still lagging behind user expectations. Due to memory size, cost, and
power considerations most palmtop computers provide only limited form of
point-to-point communication support, namely, connection via a PSTN modem
or a serial RS-232 cable. Due to wired point-to-point nature of these interfaces,
satisfactory solutions for multi-point communication and direct LAN connection
do not yet exist.
The BlueSky project aims at providing a low-cost, low-power, indoor wireless networking solution for handheld devices. Our solution consists of two components; a BlueSky wireless attachment that plugs into standard serial port of any palmtop device, and a LAN access point that acts as a layer 2/3 bridge between the wireless and wired part of the network. Palmtop devices use dialup networking software and PPP to connect via BlueSky to the network. BlueSky enables MobileIP style seamless roaming between access points without requiring any changes to the communication stack of palmtop devices. Our roaming enhancements to PPP are implemented in the PPP server, the access point, and the BlueSky attachment, all of which are completely transparent to the palmtop device. In this paper, we present our design rationale and implementation experience
of building the BlueSky system. We show in what ways low cost, low power,
and form factor constraints affect the choice of protocols and function
placement in wireless networking systems. We use PPP based mobility solution
as an example to illustrate what design adjustments and compromises one
has to make to build a working solution. Based on our experience, we recommend
making slight modification to the dialup networking stack of palmtop computers.
Our proposed modification offers an efficient, lower cost, and lighter-weight
wireless networking solution which is particularly attractive for enabling
mobility over emerging short range, low power wireless technologies, such
as HomeRF and Bluetooth.
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| Paper (postscript) |
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