RFC 5462 MPLS TC Field Definition February 2009 To avoid misunderstanding about how this field may be used, it has become increasingly necessary to rename this field. This document changes the name of the field to the Traffic Class field ( TC field ). In doing so, it also updates documents that define the current use of the EXP field. mpls exp traffic class To specify the experimental (EXP) bits that will be forwarded over a member tunnel that is part of the ClassBased Tunnel Selection (CBTS) bundle, use the tunnel mpls trafficeng exp command in interface configuration mode.
MPLS and Quality of Service Cisco Press MPLS EXP 2 field: Congestion management: LLQ 3. then you need one label per class for each flow of traffic between the two endpoints of the LSP mpls exp traffic class