Time for "Signalling System No 8" ?
It's been what 4-5 decades since first roll out.
You know certain TLA's have had to have been in through this path for decades.
Those telcos that don't use IP protocols also need to adopt defense-in-depth and can no longer assume that the next node they send to (or receive a packet from) is benign.
It may be a less trusting world for telcos, but it's a safer world for their customers.