L.4 3GPP specific encoding for SIP header field extensions

L.3 Application usage of SIP

L.2 EPS aspects when connected to the IM CN subsystem via E-UTRAN

L.2A Usage of SDP

K.3 Application usage of SDP

K.5 Application usage of ICE

K.4 Void

L.1 Scope

K.2 Application usage of SIP

I.5 Overload control