For the current Two-Way Active Measurement Protocol (TWAMP) support on MX platforms, packet timestamping is performed inline in the LU or on the ukernel of the PFE.

The TWAMP support on Advance Forwarding Toolkit (AFT) for MPC10, packet reflection and timestamping is done by AFT/PacketIO. 

The AFT is the replacement for ukernel timestamping under MPC10 and no destination-interface si-x/y/z config is required. Also the "target-address" needs to be a peer address of an interface on MPC10.

If si- interface is configured or target-address is incorrect, then TWAMP will not come up. The error below is seen when running "show services rpm twamp client connection":

Example of si- interface configured:

services {
    rpm {
        twamp {
            client {
                control-connection R3cc1 {
                    destination-interface si-7/1/0.20;  <<<< 
                    destination-port 862;
                    history-size 500;
                    target-address 160.22.0.1;
                    test-count 0;
                    test-interval 15;
                    traps {
                        test-iteration-done;
                        control-connection-closed;
                    }
                    test-session tss1 {
                        target-address 160.22.0.1;
                        data-fill-with-zeros;
                        data-size 1400;
                        probe-count 2;
                        probe-interval 1;
                    }
                }
 
@lab-re0> show services rpm twamp client connection 
error: Control-connection does not exist.  <<<

An example of correct AFT based TWAMP Client target-address Configuration:

@R1_re0# show
et-0/0/0 { <<< interface on MPC10
    unit 0 {
        family inet {
            address 50.0.0.1/24;
        }
    }
[edit services rpm twamp client]
regress@R1_re0# show
control-connection c1 {
    persistent-results;
    destination-port 862;
    history-size 500;
    target-address 50.0.0.2; <<< peer ip address of interface et-0/0/0.0
    test-count 0;
    test-interval 2;
    traps {
        test-iteration-done;
        control-connection-closed;
    }
    test-session t1 {
        target-address 50.0.0.2;
        data-fill-with-zeros;
        data-size 1300;
        probe-count 10;
        probe-interval 3;
        thresholds {
            successive-loss 1;
            rtt 50;
        }
        traps {
            test-completion;
        }

 

Remove the si- interface configuration and TWAMP session will be up.

.