Content-based publish/subscribe is a versatile communication
mechanism for building loosely coupled distributed applications.
In the past, publish/subscribe systems often required an overlay
network of cooperating brokers that inspect the content of a published
notification on the application layer in order to flexibly
make forwarding decisions. Leveraging OpenFlow-enabled network
switches, forwarding decisions can now be flexibly taken
within the network layer significantly reducing latency and jitter.

https://www.ava.uni-rostock.de/storages/uni-rostock/Alle_IEF/Inf_AVA/poster/OfPubSub.pdf

https://dl.acm.org/doi/abs/10.1145/3297280.3297589