Lucent Technologies Release 8.2 When to use IP routes, Connection When IP Routes are Needed Type

IP Addressing 1 Networking Overview

When to use IP routes

You need to define IP routes only in special cases when default gateways are not defined or when you want to limit communication between nodes. This section describes the network configurations that require explicit IP routes.

The following table summarizes when you would use IP routes:

Connection	When IP Routes are Needed:
Type
	The endpoints are on different subnets and no default
	gateway is defined on the IP Interfaces screen for the
	local node, and
	• You want the local node to communicate with only
Ethernet	the specified node on a remote subnet (this is a
	host route type), or
	• You want the local node to communicate with any
	node a remote network but not with nodes on other
	networks (this is a network route type)
PPP	There are one or more intermediate nodes between
	endpoints.

The host and network route types are not specified directly. The system implies the type from the specified destination IP address and its associated subnet mask. The route type is displayed on the IP Routing screen for the display, list, and modify commands.

The endpoint nodes are on the same subnet if the following three conditions are met:

•the endpoints are on the same physical subnetwork

•the Subnet Mask field is assigned the same value on the IP Interface screens for the two endpoint nodes

•the network + subnet portions of the IP addresses (as determined by the subnet mask) are the same

See Subnetting (page 16) for more information about subnet masks.

Administration for Network Connectivity
555-233-504 — Issue 1 — April 2000	CID: 77730	23