Lucent Technologies Release 8.2 manual Valid Value Usage, Gateway Address

Networking Screens				A Screens Reference
Subnet Mask	The subnet mask determines which part of an IP address is the network identifier and
	which part is the host identifier. The subnet mask is associated with the IP address
	administered on the Node Names screen for the IP interface identified by the Node
	Names field on this screen.
	See Chapter 1 for more information on IP addresses and subnetting.
	Valid Values		Usage
	The valid values of the subnet		This field can be used to subdivide a network
	mask depend on the IP address		into 2 or more subnetworks.
	that the subnet mask is applied to		The subnet mask consist of a string of n
	— in this case, the IP address on
			contiguous 1’s followed by a string of 32–n
	the Node Names screen that is
			contiguous 0’s. When applied to a 32-bit IP
	associated with the name entered
			address, the subnet mask indicates that the first
	in the Node Name field.
			n bits of the address form the network ID and
	In general, each octet value must		the next 32–n bits form the host ID portion of
	be one of the following numbers:		the address.
	255 or 0, corresponding to the		The following default values for the subnet
	network and host portions of an
			mask are used for no subnetting:
	IP address; or 192, 224, 240, 248,
	or 252, corresponding to using 2,		Class A addresses:	255.0.0.0
	3, 4, 5, or 6 bits from the host ID		Class B addresses:	255.255.0.0
	for the subnet ID.
			Class C addresses:	255.255.255.0
Gateway Address	Specifies the address of a network node that will serve as the default gateway for the
	IP interface.
	Valid Value	Usage
	An IP address of a	The default gateway enables communication with nodes
	bridge or router on	on (sub)networks that are different from the (sub)network
	the network that is	of the IP interface. A default gateway makes use of
	directly connected to	explicit IP routes unnecessary.
	the IP interface.	If left blank, this node (this IP interface) can communicate
	The gateway address	with nodes on different (sub)networks only if explicit IP
	must be administered	routes (on the IP Routing screen) are defined —
	on the Node Names	communication with nodes on the same (sub)network is
	screen.	not affected. With the Gateway Address left blank, you
		can enable communications with individual nodes on
		other (sub)networks by creating host IP routes to them. Or
		you can enable communication with all nodes on a
		different (sub)network by defining a network IP route to
		that (sub)network. You can define a combination of
		network and host IP routes to enable communications to
		all nodes on some (sub)networks and individual nodes on
		other (sub)networks.
Administration for Network Connectivity
555-233-504 — Issue 1 — April 2000		CID: 77730		249