The GPL license functions very simply when you get down to it.

If you don't believe what I'm about to say, you are welcome to check 
with the FSF website, and they will tell you the same thing.


As was mentioned it all comes down to distribution outside of the 
organization involved, and whether they are using the GPL or LGPL - 
which are different licenses.

The GPL stipulates that if you modify GPL code and distribute  it in any 
way outside of your organization, - source or binary, embedded or not - 
you must pass on the source code modifications to anyone who requests it 
under the GPL without additional restrictions.

Now "requests it" does _not_ mean posting to the Internet, regardless of 
what everyone thinks.

It simply means that if you give them a personal request for the code, 
they have to honour it, and turn over a copy of any changes they made. 
They are under no other obligations.

If they don't, then they are in violation of the GPL, and the author of 
the original software can either in theory: terminate their license, or 
ask the FSF  to intercede and try to negotiate a license settlement.

In practice, the FSF prefers not to get involved unless absolutely 
necessary.  They only have limited resources, and they can't put out 
every brushfire.  The GPL works primarily because everyone agrees that 
it's a good idea.

Cisco and other companies know this, and they also know that the chances 
you will actually request the code directly are slim. Distribution of 
code costs money, in bandwidth and server space.

But there is no specific stipulation requiring Internet distribution, or 
that they even have to give you the code for free.  They can charge you 
a reasonable amount for the time, shipping, and the distribution medium 
used.  But once you have it, you can exercise any of the rights of the 
GPL including reposting and so on.

Now if the code they are using is LGPL, rather than GPL, that's another 
animal.  Unlike the GPL which requires that if code is intermingled by 
compiler linking, it must also be GPL'ed  - the LGPL does not.

So if they built an application on top of Linux, without modifying the 
Linux code, that's completely closed source, because the system 
libraries in Linux used by GCC are actually LGPL.

But if they link it to any GPL code, then they would have to honour the 
GPL instead.


Cheers!
T.J.