This article explains the flapping behaviour of ICCP link for the Multi-Chassis Link aggregation Group (MC-LAG) when configured through an irb interface.

Sample Configuration:

  irb {
        unit 4094 {
            description "MC-LAG peers between switches";
            family inet {
                address 192.168.0.1/30 {
                    arp 192.168.0.2 l2-interface ae0.0 mac cc:e1:94:30:80:a0;
                }
            }

protocols {
    iccp {
        local-ip-addr 192.168.0.1;
        peer 192.168.0.2 {
            session-establishment-hold-time 50;
            redundancy-group-id-list 1;
            liveness-detection {
                minimum-receive-interval 1000;
                transmit-interval {
                    minimum-interval 1000;
                }
            }
        }
    }

Configure the ICCP liveness-detection interval (the Bidirectional Forwarding Detection (BFD) timer) to be at least 8 seconds if you have configured ICCP connectivity through an IRB interface.

A liveness-detection interval of 8 seconds or more allows for graceful Routing Engine switchover (GRES) to work seamlessly. By default, ICCP liveness detection uses multihop BFD, which runs in centralized mode.

Example:

protocols {
    iccp {
        local-ip-addr 192.168.0.1;
        peer 192.168.0.2 {
            session-establishment-hold-time 50;
            redundancy-group-id-list 1;
            liveness-detection {
                minimum-receive-interval 1000;
                transmit-interval {
                    minimum-interval 1000;    --------> The time is in milliseconds. We need to change this to 8000(8 sec) or above value.

Note: This recommendation does not apply if you configured ICCP connectivity through a dedicated physical interface. In this case, you can configure single-hop BFD.