A basic requirement for communication in a heterogeneous
computing environment is a standard external data representation.
Abstract Syntax Notation One (ASN.l) has been widely used in
international standard specifications: its transfer-syntax, the Basic Encoding
Rules (BER), is used as the external data representation. This
paper presents a BER implementation called the ED library. The EL)
library includes a number of encoding and decoding routines that may
be used as primitive functions to compose encoders and decoders for
arbitrarily complicated ASN.l data-types. Based on the ED library, an
ASN.1-C compiler, called CASNl, is designed and implemented to free
the protocol implementors from the arduous work of translating protocol-
defined data-types and constructing their encoders and decoders.
Given an ASN.l protocol specification, CASNl automatically translates
the input ASN.1 modules into C and generates the BER encoders
and decoders for the protocol defined data-types. This paper discusses
the CASNl design principles, user interface, and some example applications.
The performance of the ED library and generated CASNl code
is also measured and discussed.
