  Novel large scale research projects often require cooperation between various
different project partners that are spread among the entire world. They do not
only need huge computing resources, but also a reliable network to operate on.
The Large Hadron Collider (LHC) at CERN is a representative example for such a
project. Its experiments result in a vast amount of data, which is interesting
for researchers around the world. For transporting the data from CERN to 11
data processing and storage sites, an optical private network (OPN) has been
constructed. As the experiment data is highly valuable, LHC defines very high
requirements to the underlying network infrastructure. In order to fulfil those
requirements, the connections have to be managed and monitored permanently. In
this paper, we present the integrated monitoring solution developed for the
LHCOPN. We first outline the requirements and show how they are met on the
single network layers. After that, we describe, how those single measurements
can be combined into an integrated view. We cover design concepts as well as
tool implementation highlights.
