  Internet traffic continues to grow relentlessly, driven largely by
increasingly high resolution video content. Although studies have shown that
the majority of packets processed by Internet routers are pass-through traffic,
they nonetheless have to be queued and routed at every hop in current networks,
which unnecessarily adds substantial delays and processing costs. Such
pass-through traffic can be better circuit-switched through the underlying
optical transport network by means of pre-established circuits, which is
possible in a unified packet and circuit switched network. In this paper, we
propose a novel convex optimization framework based on a new destination-based
multicommodity flow formulation for the allocation of circuits in such unified
networks. In particular, we consider two deployment settings, one based on
real-time traffic monitoring, and the other relying upon history-based traffic
predictions. In both cases, we formulate global network optimization objectives
as concave functions that capture the fair sharing of network capacity among
competing traffic flows. The convexity of our problem formulations ensures
globally optimal solutions.
