While the datagram has served veIy well in solving themost important goals of the Internet, it has not served sowell when we attempt to addresssome of the goals whichwere further down the priority list. For example, thegoals of resource management and accountability haveproved difficult to achieve in the context of datagrams.As the previous section discussed, most datagrams are apart of some sequence of packets from source todestination, rather than isolated units at the applicationlevel. However, the gateway cannot directly see theexistence of this sequence, because it is forced to dealwith each packet in isolation. Therefore, resourcemanagement decisions or accounting must be done oneach packet separately. Imposing the datagram model onthe intemet layer has deprived that layer of an importantsource of information which it could use in achievingthese goals.
Datagrams solved the higher priority goals
...but 34 years later we have the same challenges with the lower priority goals.

