An in-band easy-to-deploy mechanism for network-to-transport signaling

Network-to-transport signaling is desirable for ensuring efficient resource usage and timely notice of network status. ICMP is the standard way for signaling, but unfortunately it generates extra load and does not traverse firewalls. In this paper, we develop M-ECN, an in-band network-to-transport signaling mechanism, which does not generate any extra packets and does not require dedicated header bits. The key idea is to sneak messages into the stream of ECN bits, but without interfering with ECN congestion signaling. Compared to other alternatives, M-ECN is easy to deploy because routers read/write to the IP header, and the mechanism requires no change to legacy routers along the path which do not participate in the signaling.