CHAPTER
16-1
ATM Switch Router Software Configuration Guide
OL-7396-01
16
Configuring Tag Switching and MPLS
This chapter describes tag switching, a high-performance packet-forwarding technology that assigns
tags to mulitprotocol frames for transport across packet- or cell-based networks.
Note This chapter provides advanced configuration instructions for the Catalyst8540 MSR,
Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. For an overview of tag switching, refer
to the Guide to ATM Technology. For complete descriptions of the commands mentioned in this chapter,
refer to the ATM Switch Router Command Reference publication.
This chapter includes the following sections:
Tag Switching Overview, page 16-1
Hardware and Software Requirements and Restrictions (Catalyst 8540 MSR), page 16-2
Hardware and Software Requirements and Restrictions (Catalyst8510 MSR and
LightStream 1010), page 16-2
Configuring Tag Switching, page 16-2
Configuring Tag Switching CoS, page 16-13
Threshold Group for TBR Classes, page 16-17
CTT Row, page 16-18
RM CAC Support, page 16-18
Tag Switching Configuration Example, page 16-19
MPLS Overview, page 16-21
MPLS Network Packet Transmission, page 16-27
Configuring Label Edge Routing, page 16-28
MPLS Over Fast Ethernet Interfaces, page 16-31
MPLS VPNs, page 16-33

Tag Switching Overview

In conventional Layer 3 forwarding, as a packet traverses the network, each router extracts forwarding
information from the Layer 3 header. Header analysis is repeated at each router (hop) through which the
packet passes.