Challenges
Challenges - How to Overcome Hardware and Software Limitations
The Arduino hardware is very powerful in the sense of provided functionality and bang for the buck. But, resources are pretty limited.
You get
- 32kB of unmodifiable (at run-time) flash memory for the program
- 2kB of volatile SRAM memory for variables, and
- 1kB runtime-programmable, non-volatile EEPROM memory for data
That's it. Pretty much any icon on your Linux, Apple, or Windows desktop is bigger then the Arduino flash memory. This is a challenge already at compile time. It gets potentially worse at run time: Processing network data requires buffers, and buffer sizes may be variable.
Configuration
Another thing is modifiable configuration (in example, WLAN credentials). If you want do to that without re-programming the chip, you need to use an interface of some kind (wireless, SPI/ I2C, or an SD card).
Updating the Firmware (OTA or Over the Air)
The Arduino itself does not provide a means to update its flash memory without some external help. But the ESP8266 or another Arduino (€2.50 from China) could do that.