Depending on the size of the network, these are partially meshed or hierarchically structured with backbone area and access network. In the backbone networks, data packets are transported via meshed UAS nodes. The access network is connected to the backbone in a linear fashion.
These networks form the access via the classic telecommunication networks to the end subscriber and the connection towards other network architectures. This connection is realized via the Frame Relay Access Devices( FRAD), which open up the world to other protocols, such as the Internetwork Packet Exchange Protocol( IPX), System Network Architecture( SNA), DECnet, the IP protocol, the UDP protocol, etc., so that they can communicate via a frame relay connection.