Emerging MPLS Applications: 
Practical Application of The Technology

John Fryer
Vice President of Marketing
NetPlane Systems
October 9, 2001

Focused Applications

Recently, there has been an increasing debate about the value of MPLS technology and the direction of the relevant standards bodies, such as the Internet Engineering Task Force (IETF), Optical Interworking Forum (OIF) and the International Telecommunications Union (ITU), as well as whether or not there are practical applications for MPLS.

The simple answer is that MPLS is alive and well and that there are, indeed, practical applications for MPLS.  The debate has focused on “how” the technology can enable critical applications, rather than “what” applications the technology could be used to support.  This debate is a natural process, driven by the rapid evolution of MPLS and the recognition that there are specific applications where MPLS can enhance service provider revenue opportunities.  Perhaps the main danger that exists for MPLS evolution is a proliferation of proprietary implementations, which when proposed to the standards organizations, leads to polarization behind leading ideas and an intractable situation, which then results in market confusion.  However, through compromise--a key element in standards body participation-- such issues can be overcome.

The key areas where MPLS deployments are already occurring, or where standards and product developments are targeted are:

• Traffic engineering of IP networks

• Layer 3 (IP) Provider Provisioned Virtual Private Networks (PP-VPNs)

• Layer 2 VPN – (metro-optical networks)

• Core optical network transport - Generalized MPLS (GMPLS)

• Optical network access – Optical User Network Interface (O-UNI)

These applications can be grouped into two broad categories – classical MPLS, focused towards Internet Protocol (IP) applications, and optical MPLS, designed to address the requirements of SONET/SDH and pure optical core networks.  Bridging these applications are Layer 2 VPNs, or metro optical applications, which seek to use modified classical MPLS techniques to supplant traditional SONET/SDH functionality. (Figure 1)

A basic examination of each of these applications demonstrates both the viability of MPLS technology and the remaining hurdles that need to be overcome to move the networking industry forward.

Traffic Engineering

The ability to provide large IP networks with Quality of Service (QoS) and Class of Service (CoS) capabilities was one of the early objectives identified by the MPLS working group inside the IETF.  The hop by hop routing mechanisms traditionally used, and the creation of Label Switched Paths (LSPs) using the Label Distribution Protocol (LDP), which mimics the hop- by- hop mechanism, provide no QoS/CoS capabilities, resulting in the “one size fits all” Internet phenomena, which makes profitable Internet/IP services such a challenge today.

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