configure flexible netflow (Transport Round-Trip-Time: Not Measured (0xffffffff))

[fkanucha1]

Hello sir.

I have question for configure flexible netflow v9 .

I config follow this https://docs.google.com.

and have problem at command ---- > collect transport round-trip-time (in TCP record)

I use wireshark to catch packet cflow. (config on router 2911/2811) and look in pkt!

Transport Round-Trip-Time: Not Measured (0xffffffff) 

I hope router send packet with RTT but now......... Not Measured.

I don't know why it happened. Who solution for me please.

THANK YOU FOR HELP.