Cisco Systems ME3400G2CSA Configuring Private VLANs

CHAPTER

12-1

Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide

78-17058-01

Configuring Private VLANs

This chapter describes how to configure private VLANs on the Cisco ME 3400 Ethernet Access switch.

Note For complete syntax and usage information for the commands used in this chapter, see the command

reference for this release.

The chapter consists of these sections:

•Understanding Private VLANs, page 12-1

•Configuring Private VLANs, page 12-5

•Monitoring Private VLANs, page 12-15

The private-VLAN feature addresses two problems that service providers face when using VLANs:

•Scalability: The switch supports up to 1005 active VLANs. If a service provide r assign s o ne V LAN

per customer, this limits the numbers of customers that the service provider can support.

•To enable IP routing, each VLAN is assigned a subnet address space or a block of addresses, which

can result in wasting the unused IP addresses and cause IP addr es s m anage men t pr oble ms.

Using private VLANs addresses the scalability problem and provides IP address management benefits

for service providers and Layer 2 security for customers.

These sections describe how private VLANs work:

•Types of Private VLANs and Private-VLAN Ports, page 12-2

•IP Addressing Scheme with Private VLANs, page 12-4

•Private VLANs across Multiple Switches, page 12-4

•Private VLANs and Unicast, Broadcast, and Multicast Traffic, page 12-5

•Private VLANs and SVIs, page 12-5