Pica8 - Open Source Cloud Switch

Tue Oct 19 15:00:23 UTC 2010

Yes "cloud computing" is a vastly overused term that is hard to nail down.
That is why I try to get people to use the specific technology term they are
talking about.

Basically in my world "cloud computing" is the vision of having computation
and storage just 'out there' without having to worry about it and just
paying for a bit more or less as you go... but its not a "technology".
Sometimes it helps to flip the term ... for example "desktop computing" is
sort of the inverse .. again its not a "technology" really either... just a
broad term but we all kind of know what it means by now, like "laptop
computing".

There seem to be too major views on technologies to make this "cloud
computing" happen. Their view on scale/transparency is considerably
different.

a) bigger layer 2 networks with Vmware type mobility and no IP address
changes. Technolgies in this space are much more than just L2 switching, its
L2 switching on larger scales with encapsulation, multipathing etc. This is
where technologies like IEEE 802.1aq Shortest Path Bridging, IEEE 802.1ah
mac-in-mac come to play. These tend to be appropriate for existing
enterprise applications (or complete virtual desktops) and simply make
existing DC L2 fabrics bigger and availale for virtualization. No
application software changes required, its done under them and end hosts
can't tell whats happening.

b) All new applications/environments that don't care if their IP address
changes and deal with it transparently. In this model you can make an
application run anywhere, move it around etc without any special
infrastructure .. the smarts are between the application and its hosts.
Basically dumb infrastructure and smart applications a.k.a over the top
stuff. I suppose the hot movement of one of these applications requires
co-ordination by the application itself while if its done below as in a) it
can be transparent.

So depending on where you sit, generically run something anywhere v.s. run
specific things anywhere you end up with slightly different underlying
technologies... both with the overused moniker 'cloud'.

Ok .. flame away .. ;)

Peter