Segmentation and reassembly of protocol data units. Segmentation may be needed since each communication network may have different size restrictions.
Advantages are less errors with smaller PDUs.
More equitable and less buffer space needed. Disadvantage of segmentation is the greater overhead and more time spent in processing with more PDUs. This means that addresses, error codes and headers must be added. Connection control of a virtual circuit if the protocol is connection oriented. In the case of connection-oriented internetworking this functionality is provided ndependently by each subnetwork.