[manigandham]

You can generate any size number in a distributed fashion. The only difference is that 128-bits gives you enough scale that it's practically impossible to have collisions when randomly generating.

Unless you need to be completely disconnected, a little coordination can drastically improve things. In past companies, I used a simple counter with 64-bit integers and each distributed process would increment a billion-number range to use for IDs. Fast, efficient, compatible with everything, naturally ordered, and guaranteed to never have a collision.