Control info includes the info that the network requires to be able to route the packet through the network and deliver it to the intended destination. At each node, the packet is received, stored briefly, and passed on to the next node. Packets are still accepted when traffic becomes heavy, but delivery delay increases. Jitter - because packets between a given source and destination may vary in length, may take different routes, and may be subject to varying delay in the switches they encounter, the overall packet delay can vary substantially. To route packets, overhead info, must be added to each packet, which reduces the communication capacity available for carrying user data.
More processing is involved in the transfer of info using packet switching.
Self-c0ntained packets carry info sufficient for routing from the originating data terminal equipment to the destination without relying on earlier exchanges between the DTE and the network. Then all packets between a pair of communicating parties follow this same route through the network. For adaptive routing to work, info about the state of the net must be exchanged among the nodes. Maintains the number of packets within the network below the level at which queuing delays become excessive. Interface between attached devices and the network.