In many cases, the most time-consuming part of the Open Systems Interconnection (OSI) protocol stack is the encoding and decoding of transfer syntax done in the presentation layer. The conventional ASN.1/BER decoding scheme runs on a whole Presentation Protocol Data Unit (PPDU). To overcome this problem, we present a new ASN.1/BER decoding scheme called Partial Decoding. The Partial Decoding scheme allows us to start decoding partially on each segment of a PPDU before a whole PPDU has been received. The measures show that the new scheme has a performance improvement as high as 40% over the conventional decoding scheme at large message size. Parallel processing for the network layer through the presentation layer is also used for a high performance protocol implementation on the basis of the proposed scheme.