C H A P T E R
5-1
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
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5
Configuring Ethernet VLAN Trunks
This chapter describes how to configure Ethernet VLAN trunks on the Catalyst 6500 series switches.
Note
For complete information on configuring VLANs, see
Chapter 11, “Configuring VLANs.”
Note
For complete syntax and usage information for the commands that are used in this chapter, refer to the
Catalyst 6500 Series Switch Command Reference
publication.
This chapter consists of these sections:
•
Understanding How VLAN Trunks Work, page 5-1
•
Default Trunk Configuration, page 5-5
•
Configuring a Trunk Link, page 5-5
•
Example VLAN Trunk Configurations, page 5-14
Understanding How VLAN Trunks Work
These sections describe how VLAN trunks work on the Catalyst 6500 series switches:
•
Trunking Overview, page 5-1
•
Trunking Modes and Encapsulation Type, page 5-2
•
802.1Q Trunk Configuration Guidelines and Restrictions, page 5-4
Trunking Overview
A trunk is a point-to-point link between one or more Ethernet switch ports and another networking
device such as a router or a switch. Trunks carry the traffic of multiple VLANs over a single link and
allow you to extend VLANs across an entire network.
Two trunking encapsulations are available on all Ethernet ports:
•
Inter-Switch Link (ISL)—ISL is a Cisco-proprietary trunking encapsulation
•
IEEE 802.1Q—802.1Q is an industry-standard trunking encapsulation