Asante Technologies 35516 Assign Multiple IP Addresses to Network Interfaces, Command Purpose

CIDR Prefix	Class C Equivalent	Host Addresses
/27	1/8 Class C	32 Hosts
/26	1/4 Class C	64 Hosts
/25	1/2 Class C	128 Hosts
/24	1 Class C	256 Hosts
/23	2 Class C	512 Hosts
/22	4 Class C	1,024 Hosts
/21	8 Class C	2,048 Hosts
/20	16 Class C	4,096 Hosts
/19	32 Class C	8,192 Hosts
/18	64 Class C	16,384 Hosts
/17	128 Class C	32,768 Hosts
/16	256 Class C	65,536 Hosts
	OR 1 Class B
/13	2,048 Class C	524,288 Hosts

An interface can have one primary IP address. To assign a primary IP address and a network mask to a network interface, use the following command, starting in global configuration mode.

Command	Purpose
Interface interface name	Enters the interface configuration mode.
ip address address l mask	Set a primary IP address for an interface.

5.1.1 Assign Multiple IP Addresses to Network Interfaces

The IC35516 software supports multiple IP addresses per interface. You can specify an unlimited number of secondary addresses. Secondary IP addresses can be used in a variety of applications:

There might not be enough host addresses for a particular network segment. Suppose your sub-netting allows up to 254 hosts per logical subnet, but you need to have 300 host addresses on one physical subnet. Using secondary IP addresses on the routers or access servers allows you to have two logical subnets using one physical subnet.

Many older networks were built using Level 2 bridges, and were not sub-netted. The use of secondary addresses can aid in the transition to a sub-netted, router-based network. Routers on an older, bridged segment can easily be made aware of multiple subnets are on that segment.

You can create a single network from subnets that are physically separated by another network by using a secondary address. In these instances, the first network is layered on top of the second network. Note that a subnet cannot appear on more than one active interface of the router at a time.

Note: If any router on a network segment uses a secondary address, all other routers on that same segment must also use a secondary address from the same network or subnet.

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