Omron CS1W-ETN21 operation manual Private and Global Addresses, FINS/UDP and FINS/TCP

Private and Global Addresses								Section 5-3
				Product		Model/Series/		Supports combined
							Version	method?
			Programmable Terminal			NS Series		No: Set manually. FINS
								communications are not
			Open Network Controller (ONC)			---
								possible with personal
								computers set automati-
								cally by DHCP.
5-2-5	Pairing IP Addresses and FINS Node Addresses
			The following table shows the methods for pairing IP address and FINS node
			addresses, and the relation between fixed and variable address, for both
			FINS/UDP and FINS/TCP.
Communi-		Method of pairing	IP address determination		Client (personal			Server (PLC)
cations		of IP addresses			computer of PLC)
method		and FINS node
					FINS node		IP address	FINS node	IP address
		addresses
					address			address
FINS/UDP		By pairing FINS	IP address	Automatic gen-	Fixed		Fixed	Fixed	Fixed
		node addresses with	conversion	eration method
		IP addresses in		(static)
		Ethernet
				Automatic gen-	Fixed		Fixed or	Fixed	Fixed
				eration method			variable
				(dynamic)
				IP address table	Fixed		Fixed or	Fixed	Fixed
				method			variable
				Combined	Fixed		Fixed or	Fixed	Fixed
				method			variable
FINS/TCP		By automatic conver-	Automatic	Connection	Fixed or		Fixed or	Fixed	Fixed
		sion of FINS node		method (auto-	can be allo-		variable
		addresses at Ether-		matic FINS	cated auto-
		net Unit and remote		node address	matically
		node (and then		conversion)	when not
		sending and receiv-			determined.
		ing data)

5-3 Private and Global Addresses

5-3-1 Private and Global Addresses

There are two kinds of IP addresses, private and global.

•Global addresses: These are IP addresses that connect directly to the Internet. Allocated by application to NIC, each address is unique in the world, and as many as 4.3 million can be allocated worldwide.

•Private addresses: These are IP addresses for Intranet (LAN) use, and cannot connect directly to the Internet. Frames that include private IP addresses are restricted by the router from being sent outside the LAN.

Generally, as shown below, global addresses in the intranet are allocated only to IP routers (such as broadband routers) interfacing with the Internet. All other nodes in the intranet, including the Ethernet Unit, are allocated private addresses.

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