A number of concerns and issues have been raised with regard to BER. We will cite some of them, but not address them in detail for the same reason we did not spend more time on the encoding rules themselves. In general, BER are widely implemented, but there is at least occasional concern about efficiency and speed. Two other issues, compactness and the number of options in BER also are worth noting.
Lin reported on a set of experiments that addressed the efficiency and processing time of ASN.1 BER. [] By applying to BER certain restrictions he considered realistic, he achieved experimental results that suggest BER is comparable to other known methods and that it can be viable when interoperability is sought.
Two enhancements of BER address the compactness and options issues. One enhancement, Packed Encoding Rules (PER), allows identifier or lenghth components to be omitted under certain conditions. PER has other features that decrease the amount of encoding necessary for transmission. In circumstances where BER offers optional ways to encode a value, the other enhancement, Distinguished Encoding Rules (DER), select a single encoding. The standard ISO 8825 consists of three parts, one for each of BER, PER, and DER.