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MultiProtocol Label Switching (MPLS) Source Label

Document Type Expired Internet-Draft (mpls WG)
Authors Mach Chen , Xiaohu Xu , Zhenbin Li , Luyuan Fang , Greg Mirsky
Last updated 2015-04-16 (Latest revision 2014-10-13)
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
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Stream WG state Candidate for WG Adoption
Polled for WG adoption but not adopted
Document shepherd Ross Callon
IESG IESG state Expired
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)
This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at:


A MultiProtocol Label Switching (MPLS) label was originally defined to identify a Forwarding Equivalence Class (FEC). A packet is assigned to a specific FEC based on its network layer destination address, and optionally Class of Service. It's difficult or even impossible to derive the source identity information from the label. For some applications, source identification is a critical requirement. For example, performance monitoring, where the monitoring node needs to identify where a packet was sent from. This document introduces the concept of Source Identifier (SI) that identifies the ingress Label Switching Router (LSR) of a Label Switched Path (LSP). A SI is unique within a domain that is referred to as Source Identifier Administrative Domain (SIAD). This document also introduces the concept of Source Label (SL) that is carried in the label stack and carries the SI of the ingress LSR of an LSP. Source Label is preceded by a Source Label Indicator (SLI) when included the label stack and is not used for forwarding.


Mach Chen
Xiaohu Xu
Zhenbin Li
Luyuan Fang
Greg Mirsky

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)