RLC/MAC layer in real networks is always used in acknowledged/reliable mode, and LLC is always only used in unreliable (UI) mode. The reason for this is that TCP cannot deal with the enormous packet loss that GPRS or similar radio links pose. If TCP would be exposed to the real packet loss, it would stall way too much. So my rationale was to use the same while creating osmo-sgsn. We use LLC in UI mode. Or are we talking about something completely else? Regards, Harald -- - Harald Welte <laforge@gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)