For indicating lost segments (LS) across layer boundaries an application encoder (AE) generates independently accessible symbols (Sym) , these symbols (Sym) are aggregated by symbol aggregation means (SA) into a packet payload, the aggregated symbols in the packet payload are transported in a defined packet structure (P1) whereby the packet structure (P1) is defined by anyone of at least one packet header, a block- check sequence, and a payload of variable length of aggregated independent symbols, these packets are transported over a channel by a packet transmitter (PT) segmenting the packets into different segments (S2) by segmentation means (SE), a segment receiver (SR*) included in a first entity has the ability to detect whether a certain segment is lost and also knows the length of the lost segment, the segments are aggregated in the first entity to form at least one packet conforming to the packet stream, the one or more packets are delivered to a packet receiver (CPS) in another, second entity by means of a normalized interface (Nil) between the two entities which allows to pass packets according to the specified format from the first entity to the second entity, a symbol parser entity (CPS) recovers the symbols and passes the individual symbols (Sym) to an application decoder (AR), whereby either correct symbols or erased symbols can be forwarded to the application decoder, the segment receiver (SR*) in the first entity inserts a certain pattern at the position where the lost or defective segment would be which indicates the loss or defect of segment and the length of the lost or defect segment in the aggregated packet, the packet receiver (CPS) in the second entity knows the format, the syntax and the semantics of the inserted pattern, means in the second entity search for specific patterns in the received packet (RP1*) and interpret each found pattern to recover all reliable non-lost information within the packet, and a symbol parser (CPS) in the second entity recovers from the recovered non-lost information of each received packet (RP1*) individual symbols (Sym).