  In this note we consider the survivable network design problem (SNDP) in
undirected graphs. We make two contributions. The first is a new counting
argument in the iterated rounding based 2-approximation for edge-connectivity
SNDP (EC-SNDP) originally due to Jain. The second is to make some additional
connections between hypergraphic version of SNDP introduced by Zhao, Nagamochi
and Ibaraki and edge and node-weighted versions of EC-SNDP and
element-connectivity SNDP (Elem-SNDP). One useful consequence of this
connection is a 2-approximation for Elem-SNDP that avoids the use of set-pair
based relaxation and analysis.
