The SS7 signaling transfer point (STP) market (product revenue only) contracted 17% in 2017 to reach $360 million. This decline is partially offset by a strong increase in the signaling firewall market. We forecast that very strong growth in the signaling firewall market will not be enough to offset declines in the legacy SS7 STP market (-13% CAGR) and that the aggregate market will decline by an average of 5% per year through 2022.