This is actually kind of a complicated question, depending on why you're asking, and more specifically, the behavior you expect.
All .deb files are "Debian packages", and that is technically correct, regardless of the distro or version of distro you're referring to. The same is true of "RPM", as all are "Red Hat packages". Specific files refer to the utilities to manage them, namely dpkg (The Debian Package Manager) and RPM (The Red Hat Package Manager).
The confusion stems from the fact that in addition to "installing packages", most users are used to "installing software", which is a complex process of "finding the software, installing it's dependencies, unpacking it, and configuring it for use on a user's system."
For instance... as of today (1 Jan, 2015), downloading and installing the sudo package from Ubuntu Trusty on an x86_64 system doesn't matter if you do:
wget http://mirrors.kernel.org/ubuntu/pool/main/s/sudo/sudo_1.8.9p5-1ubuntu1_amd64.deb; sudo dpkg -i sudo_1.8.9p5-1ubuntu1_amd64.deb
sudo apt-get update; sudo apt-get install sudo -y
Deviations from that cause problems even with timing.
The dpkg file in question here has some specific things going for it.
- It is for the 'sudo' package.
- It is of version 1.8.9p5
- It is Ubuntu epoch 1
- It is version 1 of epoch 1 of version 1.8.9p5 of sudo.
- It is compiled for the x86_64 architecture.
Attempts to install this Debian package via dpkg will (almost) always fail on say, Raspbian, which is built with Debian dependencies and a different architecture.
apt-get install sudo
Will almost always work. The difference lies in how the package manager, and the dependency resolver, are configured.
If you want a user to install "sudo", you should refer them to their dependency resolve, like aptitude, yum, or apt-get.
If you want them to work with a specific package, suck as "convert this Debian package to an RPM via alien", you deal with specific packages.