https://app.knowbase.one/vault/rfc/docid/1132
RFC3032: MPLS Label Stack Encoding
Network Working Group E. Rosen Request for Comments: 3032 D. Tappan Category: Standards Track G. Fedorkow Cisco Systems, Inc. ...
https://app.knowbase.one/vault/rfc/docid/4581
RFC4182: Removing a Restriction on the use of MPLS Explicit NULL
Network Working Group E. Rosen Request for Comments: 4182 Cisco Systems, Inc. Updates: 3032 September 2005 Category: Standards Track Removing a Restriction on the use of MP...