Layer 3-Based VLANs
Layer
The
Even though a switch inspects a packet’s IP address to determine VLAN membership, no route calculation is performed, the RIP protocol is not employed, and packets traversing the switch are bridged using the Spanning Tree algorithm.
A switch that implements layer 3 (or ‘subnet’) VLANs without performing any routing function between these VLANs is referred to as performing ‘IP Switching’.
IP Addressing and Subnetting
This section gives basic information needed to configure your Layer 3 switch for IP routing. The information includes how IP addresses are broken down and how subnetting works. You will learn how to assign each interface on the router an IP address with a unique subnet.
Definitions
•IP Address – the unique number ID assigned to each host or interface on a network. IP addresses have the form xxx.xxx.xxx.xxx.
•Subnet – a portion of a network sharing a particular network address.
•Subnet mask – a
•Interface – a network connection
•IP Interface – another name for subnet.
•Network Address – the resulting
•Subnet Address – another name for network address.
IP Addresses
The Internet Protocol (IP) was designed for routing data between network sites. Later, it was adapted for routing between networks (referred to as “subnets”) within a site. The IP defines a way of generating a unique number that can be assigned each network in the internet and each of the computers on each of those networks. This number is called the IP address.
IP addresses use a “dotted decimal” notation. Here are some examples of IP addresses written in this format:
1.210.202.204.205
2.189.21.241.56
3.125.87.0.1
This allows IP address to be written in a string of 4 decimal (base 10) numbers. Computers can only understand binary (base 2) numbers, and these binary numbers are usually grouped together in bytes, or eight bits. (A bit is a binary digit – either a “1” or a “0”). The dots (periods) simply make the IP
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