O'Reilly logo

MPLS Fundamentals by Luc De Ghein - CCIE No. 1897

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Introducing MPLS Labels

One MPLS label is a field of 32 bits with a certain structure. Figure 2-1 shows the syntax of one MPLS label.

Figure 2-1. Syntax of One MPLS Label

The first 20 bits are the label value. This value can be between 0 and 220–1, or 1,048,575. However, the first 16 values are exempted from normal use; that is, they have a special meaning. The bits 20 to 22 are the three experimental (EXP) bits. These bits are used solely for quality of service (QoS).

Note

These bits are named “experimental” for historical reasons. At one time, nobody knew what they were going to be used for. Chapter 12, “MPLS and Quality ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required