Hi JDK,

Well, as you said, there's no mechanism for STP1 to alert/inform MSC1 to keep sending traffic for CdPA 987654321 when STP1 cant process it further to the next hop. I guess everyone agrees on it and we can call it "limitation" of SS7?

For your idea (second route to STP2), I guess it will depends on specific STP vendor, since you will do first route on NI=3, and second route on NI=2. I dont know whether STP can do this.