GE 90*-30 PLC Series User Manual

Also see for 90-30 PLC: Installation and Hardware Manual

Contents

GFK-1322 Appendix D Glossary D-7DName Usually, this refers to the Network Address Name. For DistributedDirectory Protocol operation, this can sometimes refer to a Long-Form name, which is a combination of a Network Address Name anda specific Device Name at that network adapter.Netid The netid is the part of the IP address identifying the network onwhich the node resides. (See also Hostid.)Network An arrangement of nodes and interconnecting branches.Network Adapter The device, such as the Ethernet Interface, providingcommunications services for a particular network.Network Address Name A character string that is used in lieu of an actual IP address. Theclient device uses Name Resolution to resolve this symbolic nameinto the actual IP address. This name represents the address on thenetwork of a particular network adapter.Node The physical module that connects a node to the network. TheEthernet Interface is an example of a node. It connects a station (PLCor CNC) to a network (Factory LAN). A station may contain morethan one Ethernet Interface and therefore contain more than onenode.Octet A group of 8 bits operated on as a single unit. (See also Byte.)One-Way Propagation Time See Transmission Path Delay.Path The sequence of segments and repeaters providing the connectivitybetween two DTEs. In CSMA/CD networks, there is one and onlyone path between any two DTEs.Peer Another entity at the same level (layer) in the communicationhierarchy.Peer-Peer Communication between nodes at the same level or layer in thehierarchy.Physical Address The unique physical layer address associated with a particular nodeon the Local Area Network (LAN). Ethernet physical addresses aretypically assigned by the manufacturer. (See for comparison, InternetAddress.)Protocol A set of rules for exchanging messages between two communicatingprocesses.Protocol Data Unit (PDU) Information that is delivered as a unit between peer entities of a localarea network (LAN) and that contains control information, addressinformation, and may contain data.Remote Station Station located elsewhere on the network. (See also “Local Station”)Repeater In a Local Area Network, a device that amplifies and regeneratessignals to extend the range of transmission between network nodes orto interconnect two or more segments.Responding Station A station which generates a message in response to a command thatwas directed to the station.Round-Trip Propagation Time Twice the time required for a bit to travel between the two mostdistant nodes in a bus network.NOTE: In a network using carrier sense, each frame must be longenough so that a collision or jam signal may be detected by thetransmitting node while this frame is being transmitted. Its minimumlength is therefore determined by the round-trip propagation time.Router A device similar to a bridge that allows access to multiple LANs.(Also known as a gateway in Internet terminology.)