Cyclades Router OS License

[Luiz Felipe <luiz@grupocarvalho.com.br>]

Hi list,

my firm recently purchased a Cyclades Router and i had seen that the OS 
that runs into the hardware is more expansive than the hardware itself.

Cyclades' OS is a Linux. So, ins't Cyclades, by implications of GPL, 
forced to publish its sources ?

I would like to make an OS for a router in my University's conclusion 
work, but I don't know the internals of an Router hardware, and i think 
that the only way to know this is getting the source of an OS.

Thanks for every help.

--
Atenciosamente,
Luiz Felipe de souza Gomes
Network Administrator