A Brief History of MPLS

Multiprotocol Label Switching has been a staple of enterprise connectivity for years now. But when and how did this technology come to pass, and how has it remained a mainstay of corporate networking?

What is MPLS?

MPLS is a specific type of protocol that enables the transmission and shaping of network traffic, TechTarget noted. As opposed to passing through the routing level of a network, MPLS allows for data packets to be transmitted at Layer 2, the switching level. In this way, packet forwarding can take place and network paths can be determined based on the labels obtained after packets enter service provider networks.

MPLS: A capable alternative

According to Infocellar, MPLS as we know it today was established in 1997 by the Internet Engineering Task Force, coming as an alternative to multilayer switching and IP-over-ATM.

IP-over-ATM, one of the earliest routing protocols utilized, allowed for Layer 3 functionality, but was only leveraged on the edges of networks. As consumer and corporate networking demands grew, service providers soon realized the limitations of IP-over-ATM, particularly when it came to scalability.

As a result of these challenges, multilayer switching in the form of integrated ATM switching and IP routing began being widely adopted in 1996. However, telcos and technology vendors which had established multilayer switching systems – including IP switching, tag switching and aggregated route-based IP switching – began to identify the shortcomings of these types of solutions.

MPLS allows for improved traffic shaping capabilities and Quality of Service support.

MPLS allows for improved traffic-shaping capabilities and Quality-of-Service support.

“Although these approaches had a number of characteristics in common, they were not interoperable because each relied on different technologies to combine IP routing and ATM switching into an integrated solution,” Infocellar noted. “The challenge facing the ISP community was that each solution was proprietary and therefore not interoperable.”

This obstacle led to the creation of MPLS in 1997, which became the industry standard for interoperable multilayer switching. The IETF worked to establish MPLS, maintaining the IP functionality while eliminating ATM protocols and utilizing MPLS label switching.

The rise of MPLS

MPLS was made widely available in 2001, and ISP and enterprise network engineers quickly recognized the benefits this technology could offer.

“MPLS’s Quality of Service support enables users to gain insights about latency, jitter and packet loss.”

“With advancement in packet switching, MPLS overcomes ATM setbacks with less overhead and connection-oriented services for frames and varying length,” MPLS Info stated. “This also provides the advantage of maintaining traffic engineering and out-of-band control. Thus, Frame Relay and ATM are less in need for installing large-scale networks, as MPLS performance is far superior to previous [protocols].”

As MPLS deployments grew, TechTarget noted that a number of other advantages became clear as well, including:

  • Outsourced routing, which freed users from having to handle WAN routing themselves.
  • Any-to-any traffic patterns through interconnected sites for a range of applications, including VoIP and video conferencing.
  • Quality-of-Service support, enabling users to gain insights about latency, jitter and packet loss. This capability ensures that data packets associated with sensitive apps like voice and video can be prioritized over other types of traffic.

More than a decade of success

Around the time of MPLS’s 12th birthday, Network World highlighted the protocol’s continued success, noting that its flexibility, neutral nature, adaptability and scalability helped it become an industry standard.

“MPLS is one of our wildly successful protocol suites,” Loa Andersson, IETF MPLS Working Group co-chair, told Network World in 2009.

Even now that alternatives – including Internet as WAN – are available, MPLS is still a connectivity mainstay in the majority of corporate networks.

“[MPLS] is not dead,” said Gartner research director Andrew Lerner. “It’s still a backbone of most WANs. It’s just being supplemented with other technologies like Ethernet and Internet.”

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Categories: Application Performance/Application Quality, IT Challenges, Network Reliability, Internet as WAN (MPLS Alternatives)