We address the quantitative comparison of two basic connection schemes for on-chip communication, connection-oriented and connection-less, regarding their enforcement of a defined Quality-of-Service for the communication. For such comparison, we have built similar models for the two approaches, whose simulation highlights the drawbacks and opportunities of each solution. We demonstrate that for variable bit-rate applications, the end-to-end delay for the individual flows is less stable in the connection-oriented scheme than in the connection-less scheme.