Hi @Muthukumar1 !
MAC address of the L3 interface doesn't matter in this case, your connection interrupts on Layer 7, not Layer 2. When you connect to an IRF stack using SSH you initiate connection to the MPU which is current IRF Master. When Master-Backup failover happens you need to re-establish the SSH session, because there is no SSH state sync in IRF and new Master (former Backup) knows nothing about this SSH connection.