Such a scheme, however, is required to permit autonomous IMP operation in case of the failure of the calculating node. Traffic statistics would be gathered by the IMP's and transmitted to the calculating node under some form of control from the latter. This control could well extend to the connection and disconnection of circuit switched circuits throughout the network. The second version of the network protocol was reviewed. No firm decision evolved.
Error detection depends upon two cyclic redundancy characters.
The structure of the packet header was examined. To facilitate the reordering of packets received out of time sequence, a packet number was introduced. Also, the notion of a variable length header was developed to improve the utilization of message bits. Thus, short headers could be used with short, simple messages, and long headers with long, complex ones. The IMP was viewed conceptually as consisting of a network part and a host part.