Although each link guarantees that an IP datagram sent over the link will be received at the other end of the link without errors,it is not guaranteed that IP data grams will arrive at the ultimated estination in the proper order.WithIP,datagrams in the sameTCP connection can takedifferent routes in the network,and therefore arrive out oforder.TCP is still needed to provide the receiving end of the application the byte stream in the correct order.Also,IP can lose packets due to routing loops orequipment failures.