"The single biggest problem with communication is the illusion that it has taken place."
- George Bernard Shaw
As discussed in the previous section, IP provides a connectionless service. There is no acknowledgement mechanism in the IP layer, and the IP packets are routed at every hop from the source to the destination. Hence, it is possible that some packets sent by the transmitting node are lost on the network due to errors, or are discarded by the intermediate devices due to congestion on the network. Hence the receiving node will never receive the lost packets in the absence of a feedback mechanism.
Further, if there are multiple paths on the network to reach the destination from the source, it is possible ...
