When the text encoding of [ITU-TH.248.1] is used, local descriptors (LD) and remote descriptors (RD) consisting of "session" descriptions are based on the session description protocol (SDP) (clause 7.1.8 of [ITU-T H.248.1]). As a result, SDP information elements are embedded in the H.248 protocol syntax. The encoder/decoder for H.248 Messages for Annex B of [ITU-T H.248.1] text mode therefore comprises of an SDP encoder/decoder in addition to the basic H.248 encoder/decoder.