By now you’ve seen speculation that the Malaysian Airlines flight in Ukraine was brought down by a “Buk” missile system. The NATO code name for this system is either SA-11 GADFLY or SA-17 GRIZZLY for the follow-on variant. The Russian (and Ukraine) name for the system is “Buk.”
Both Russia and Ukraine operate the Buk. And the pro-Russian separatists in eastern Ukraine claim to have captured some.
A Buk battery consists of a command post vehicle, a surveillance radar vehicle, several launcher vehicles, and vehicles carrying reloads. But the SA-11/17 can be fired and guided solely from its launcher vehicle, without integrating with the command post and surveillance radar.
The system is highly mobile, and intended to provide air defense for army formations in the field, though Ukraine does also use it as a portion of their fixed national air defense network protecting its cities and critical infrastructure.