It's times like these that I wish I was more informed about military equipment. Sure, I know the basics, but when it comes to some more antiquated equipment like this, it's hard for me to say what it is for sure. I believe that this line of vehicles are BM-24Ms mounted on the ZIL-157 6x6 truck.
The BM-24 is a Soviet designed multiple rocket launcher (MRL) with 12 launch tubes capable of launching 240mm rockets. It was originally designed around 1949-1951, and North Korea is believed to have 200 of these MRLs.
Parade of rocket launchers rolls through Pyongyang in the Democratic People's Republic of Korea.