Why i can't recv rni number?

Asterisk 11.4.0
chan_ss7 version 2.2.0

USE CHINA SS7 ISUP

for Examples:

USER A : 1000
USER B : 2000
USER C : 3000

B call forward To C
and then A call to B

in asterisk cli mode i only see about this:
– Recv IAM CIC=5 ANI=1000 DNI=3000 RNI= redirect=yes/0 complete=0

quesstion:why RNI is empty?

As this is received, because that is what the network operator sent.

hi david55,
thanks,but operator have sent to me , because use the ss7 isup