Distech Controls ECLYPSE APEX, Руководство пользователя

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12 ECLYPSE APEX
CHAPTER 2
Internet Protocol Suite Fundamentals
This chapter describes the Internet protocol operating principles necessary to configure the IP param-
eters of an IP controller.
About the Internet Network
The Internet is the world-wide interconnection of networks. At its root however, it is not one big net-
work, but a group of networks that communicate between each other by using standard protocols and
by using gateways between these networks called routers.
The structure of the Internet is decentralized and non-hierarchical. On the Internet, all communication
uses the Internet Protocol (IP) to communicate and all connected devices are identified by their IP ad-
dress. An Internet Registry allocates IP addresses to internet service providers to be used by their
users.
Data is sent across the network in packets. Each packet has a header that identifies the sender’s and
intended receiver’s IP addresses.
Internet Protocol Suite Overview
Internet Protocol (IP) is part of a multi-layered suite that together enables data communication. The
following descriptions are an overview of the IP suite protocol layers as used by IP devices:
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Physical layer (bits): This is the physical and device-to-device electrical connection layer otherwise
known as Ethernet. This layer defines:
– The requirements for the physical connection between devices (the signal medium). For exam-
ple, RJ-45 connectors (attached per TIA/EIA-568-A,), using Cat 5e data cable. The maximum
cable length between devices is 328 ft. (100 m) at 100 MB/s data rate.
– The electrical signal requirements for data packet transport.
– The data packet structure including data payload and the source and destination device’s MAC
addresses.
In the case of Wi-Fi connected devices, the link layer is the air interface defined by the Wi-Fi standard,
such as radio frequencies, data rates, authentication, data channel encryption, and so on.
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Data Link layer: This layer implements the ability for two devices to exchange data with each
other.
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Network layer: This layer implements the ability to connect multiple distinct networks with each
other. It provides the internetworking methods that allow data packets to travel from the source de-
vice to a destination device across network boundaries, such as a router through the use of an IP
address. See
About Routers, Switches, and Hubs .
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Transport Layer (segments): This layer provides end-to-end communication data stream connec-
tion between two or more devices through a variety of protocols. However, it is the Transmission
Control Protocol (TCP), the most commonly used internet transport protocol that is used by Dis-
tech Controls IP controllers to communicate with each other. TCP creates a connection-oriented
channel between two applications; that is to say the data stream is error-checked, is sorted into
the correct sequence (missing data packets are re-transmitted) and this data stream has a port
number for addressing a specific application at the destination host computer.
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Session layer (data): This layer implements the protocol to open, close, and manage a session be-
tween applications such that a dialog can occur.
Internet Protocol Suite Fundamentals