  In this paper, new equivalence relationships between a network code with link
errors (NCLE) and an index code with side information errors (ICSIE) are
studied. First, for a given network coding instance, the equivalent index
coding instance is derived, where an NCLE is converted to the corresponding
ICSIE and vice versa. Next, for a given index coding instance, the equivalent
network coding instance is also derived, where an ICSIE is converted to the
corresponding NCLE and vice versa if a pair of encoding functions of an
original link and the duplicated link are functionally related in the network
code. Finally, several properties of an NCLE are derived from those of the
equivalent ICSIE using the fact that the NCLE and the ICSIE are equivalent.
