IEC 61334-4-61:1998 pdf download – Distribution automation usingdistribution line carrier systems -Part 4-61: Data communication protocols – Network layer – Connectionless protocol

IEC 61334-4-61:1998 pdf download – Distribution automation usingdistribution line carrier systems -Part 4-61: Data communication protocols – Network layer – Connectionless protocol.
This part of IEC 61334 covers the services required of. or by, the DCP netwotk layer (N) sublayer entity at the logical interfaces with the N user layer and the LLC sublayer, using the connectionless N procedures.
Services are specified showing the information flow between the N user and the LLC service. by describing the service primitives and parameters which characterize each service.
The primitives in Ibis standard are associated with the connectionless N potocol, providing connectionless services.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text. constitute provisions of this part of IEC 61334. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC 61334 are encouraged to investigate the possibility of applying the most recent editions of normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
lEG 61334-4-1:1996. Distribution automation using distribution line carrier systems — Part 4:
Data communication protocols — Section 1: Reference model of the communication system
lEG 61334-4-33:1996, Distribution automation using distribution line corner systems — Part 4- 33: Data communication protocols — Data link layer — Connection onenteci protocol
IEC 61334-4-41:1996, Distribution automation using distribution line carrier systems — Part 4:
Data communication protocols — Section 41: Application protocols — Distribution line message specification
IEC 61334-4-42:1996, Distribution automation using distribution line carrier systems — Part 4; Data communication protocols — Section 42: Application protocols — Application layer
ISO/IEC 7498: Information technology — Open Systems Interconnection — Basic Reference Model
2 N service definition
The N service primitives allow a connectionless, unacknowledged data transfer at the N-user interlace, improving the addressing capabilities of the underlying LIC service.
The N data transfer prlmtive refers to a neiwork address and. In the general case, while in the global network two or more stations belonging to different subnetworks may have the same MAC station address, each of them will be univocally edentilied by its own unique network address
In details, an N user is identified by its title composed by a network address and a NSAP selector, in a similar way as specified In IEC 61334-4.1.
A message coming from an N user has assoc*aled the network destination address and the N- entity should map it in a transmission request to the underlying LLC sublayer, with an associated LLC destination station address of the next station involved in the network path to be traversed by the message
The LLC destination station address is composed of two parts: the LSAP selector (the fixed value 01 Hex assigned to the referenced Symbol N-entity_LSAP, identifying the N-entity LSAP) and the MAC address.
Therefore, each N-entity has to have a table (routing table) to execute the addressing translation between the network destination address and the next-hop station LLC address.
The N-entity recognizes also its own local station network address, so that the messages for its local N-users are not routed to the next-hop station btit delivered to them,
The services assumed from the LLC sublayer are those related to the LLC connection oriented (LLC-CO) protocol mode, which supports bl-d.rectional full-duplex connectionless LIC service of data transfer,
It should be noted that the network layer does not support segmentation nor reassemblin9 of data: that means the NSDUs have to be a maximum sizo compatible wdh the size supported by all the involved subnetworks.
The services are described in an abstract way.