The distribution of broadcast TV across large
provider networks has become a highly topical subject as satellite
distribution capacity exhausts and competitive pressures increase.
In a typical IPTV architecture, broadcast TV is distributed from
two sources (for redundancy) to multiple destinations. The aim
of this paper is to examine how IPTV can be reliably and cost
effectively supported in wavelength division multiplexed (WDM)
networks. WDM networks have evolved to mesh topologies and
recently to support multicast, which is particularly valuable in
reducing the network cost in broadcast TV applications.
Our goal is to find two trees with a minimal total cost such that
we have two physically (or Shared Risk Link Group (SRLG))
diverse paths to each of the destinations – one from each of
the sources. Any two links that belong to a common SRLG are
subject to a single point of failure, be it a channel or wavelength
failure, a fiber cut, or a complete conduit cut. We first show
that our path protection routing problem is NP-complete. We
then propose an Integer Programming (IP) formulation for this
problem. Using real network topology data, we show that the
real networks are amenable to the IP problem formulation and
yield optimal solutions.