CHAPTER

4-1
Layer 3 Switching Software Feature and Configuration Guide
78-6235-04, Cisco IOS Release 12.0(10)W5(18)
4
Configuring Interfaces
This chapter describes basic interface configurationsfor your Layer 3 switch router. Also included are
sections about configuring virtual LANs (VLANs), packet-over-SONET interfaces, ATM uplink
interfaces, and port snooping.
Unless otherwise noted, the information in this chapter applies to the Catalyst 8540 CSR,
Catalyst 8510 CSR, and Catalyst 8540 MSR with Layer 3 functionality. For further information about
the commands used in this chapter, refer to the command reference publications in the Cisco IOS
documentation set and to Appendix A, “Command Reference.”
This chapter includes the following sections:
•Overview of Interface Configuration
•General Instructions for Configuring Interfaces
•About Layer 3 Switching Interfaces
•About Virtual LANs
•Configuring ISL VLAN Encapsulation
•Configuring 802.1Q VLAN Encapsulation
•About Packet over SONET (Catalyst 8540)
•Configuring the POS OC-12c Uplink Interface (Catalyst 8540)
•About ATM Uplinks (Catalyst 8540)
•Configuring the ATM Uplink Interface (Catalyst8540)
•About Port Snooping
•Configuring Snooping
Note You are at Step 3 in the suggested process for configuring your switch router (see the
“Suggested Procedure for Configuring Your Switch Router” section on page2-1). You
should have already configured the processor module (and LAN emulation on the
Catalyst 8540 MSR) and now be ready to proceed with configuring interfaces.