Router Installation and Configuration Manual/Configuring MPLS
From ImageStream Router Documentation
Multiprotocol Label Switching (MPLS) is a mechanism in high-performance telecommunications networks which directs and carries data from one network node to the next. MPLS makes it easy to create "virtual links" between distant nodes. It can encapsulate packets of various network protocols.
MPLS support was introduced in ImageStream Linux version 4.4.0-41. This release contained MPLS kernel forwarding plane support for functionality as both a Label Switch Router (LSR) and Label Edge Router (LER) as well as Label Distribution Protocol (LDP) with OSPF.
Creating an MPLS Core Network using the Label Distribution Protocol (LDP)
ImageStream's MPLS implementation utilizes the Label Distribution Protocol (LDP) between MPLS-enabled routers to create Label Switched Paths (LSPs). Configuring LDP