MPLS Layer Details

MPLS (Multiprotocol Label Switching) can be thought of as a shim-layer between Layer 2 and Layer 3 of the protocol stack. MPLS provides connection services to Layer 3 functions while making use of link-layer services from Layer 2. To achieve this, MPLS defines a shim header that is inserted between the link layer header and the network layer header of transmitted frames. The format of a 32-bit MPLS shim header is illustrated in the following figure.

Click to expand in new window
MPLS Shim Header
GUID-2775C131-0C57-4E74-8B8F-165B54105A57-low.png