Hanspeter Portner <dev@open-music-kontrollers.ch> schrieb am So., 3. Jan. 2016 um 09:28 Uhr:

As others have pointed out already, SLIP is merely used as a means of
framing packet data (e.g. IP, OSC) on 'unreliable' streams (e.g. serial
lines). Some clients (e.g. PureData) even use it for 'reliable' streams
(e.g. TCP).

SLIP is mandatory for OSC over TCP in OSC protocol version 1.1. Hence, you should use it when using OSC over TCP. IIRC it is optional in liblo.