  A recent advance in networking is the deployment of path-aware multipath
network architectures, where network endpoints are given multiple network paths
to send their data on. In this work, we tackle the challenge of selecting paths
for latency-sensitive applications. Even today's path-aware networks, which are
much smaller than the current Internet, already offer dozens and in several
cases over a hundred paths to a given destination, making it impractical to
measure all path latencies to find the lowest latency path. Furthermore, for
short flows, performing latency measurements may not provide benefits as the
flow may finish before completing the measurements. To overcome these issues,
we argue that endpoints should be provided with a latency estimate before
sending any packets, enabling latency-aware path choice for the first packet
sent. As we cannot predict the end-to-end latency due to dynamically changing
queuing delays, we measure and disseminate the propagation latency, enabling
novel use cases and solving concrete problems in current network protocols. We
present the Global Latency Information Dissemination System (GLIDS), which is a
step toward global latency transparency through the dissemination of
propagation latency information.
