How MPLS works

A private MPLS VPN network delivers the highest reliability, agility, visibility and simplicity for connecting a global enterprises’ complex and highly distributed ecosystem of employees, customers and partners.

Let’s start with the reliability question. Every company must ask how critical network performance and quality are to its business strategy. Whether it’s an extended enterprise with locations around the globe or a local business, most companies will determine that a secure, robust and efficient communications infrastructure is a requirement for competing in today’s always-on global economy. Many customers cannot tolerate any network down-time.

Companies that provide private MPLS networks, such as Verizon, will typically commit to 100% availability of their core network, but will also put in place rigorous quality and process demands on the local access partners they use so the end-to-end quality can actually be guaranteed upfront.

If Murphy’s Law strikes and something does go wrong, all of the e-bonding processes in place will ensure any outage is dealt with swiftly. MPLS VPNs also offer the simplicity and peace of mind that the end-to-end network solution, including access components, are being managed efficiently by the solutions provider, freeing up the customer to concentrate on its core business.

The reliability factor however is only the baseline for ensuring that an underlying technology will be deemed the standard bearer of corporate networks.  The more challenging issues are driven by quality elements -- e.g. latency, packet loss, mean opinion scores, etc. -- that are essential for successful transport of applications.  

What's next for MPLS?

Consider, for example, the convergence of data, voice and video, which has been a primary driver of the MPLS VPN market because of MPLS’ inherent ability to prioritize traffic and ensure consistent performance. Customers that rely on their MPLS VPN network for converged communications need the ability to optimize the use of these resources, without compromising quality, which is where visibility comes into play.  

Complete visibility into a corporate network is a necessity, and customers have come to rely on MPLS tools for tracking and predicting actual usage and performance down to the bandwidth and application levels. This enables efficient troubleshooting and obviates the need to fix every problem by blindly throwing additional bandwidth into the network and hoping for the best.  

That being said, when additional bandwidth is the answer, MPLS networks are dynamic enough to allow customers to allocate additional bandwidth as needed or change classes of service settings to accommodate regularly recurring events, such as a weekly SAP back-up, or occasional events, such as a live stream video of the CEO.

Today, with enterprise mobility and cloud computing adoption on the rise, the application landscape is rapidly evolving. Whether an enterprise centrally hosts its applications or not, the key to a successful computing environment depends on the accessibility and security of applications and data, all of which rely upon the quality and security of the network.  

A recent report by research firm Ovum titled “Cloud Computing: What’s the Network got to do with it?” put it well:  “We think the network is an essential part of telcos' value propositions as cloud computing applications move from public IP, with no QoS or SLA guarantees, to trusted networks.”

Indeed, the need for cloud applications to communicate effectively over the WAN will become increasingly critical in network selection, a fact that plays to the strengths of MPLS VPNs.  

The quality, reliability, flexibility and simplicity of MPLS VPNs is a perfect complement to the emerging cloud-driven computing world, so much so that MPLS services will become analogous to the electric grid. That is, always on and operating reliably, yet invisible, to the point that when cloud customers ask themselves what the network has to do with it we will argue . . . everything.

Private WANs using Multiprotocol Label Switching (MPLS) or leased lines look very different economically. In the United States, MPLS pricing ranges from $350 to $700 per megabit per month for 1.5Mbps of bandwidth. Internationally, locations pay as much as the equivalent of $5,000 per month for a 2Mbps connection. Yet, consumers buy high-speed Internet connections boasting 20M or 50Mbps of connectivity for as little as $4 per megabit per month.

Why are businesses willing to spend a fortune on services like MPLS when cheap Internet is abundantly available?

Until now, the only way to get reliable connectivity with predictable performance between corporate locations was to buy leased lines or a service like MPLS. Enterprises require the 99.99%, four nines, reliability that MPLS offers with Quality of Service (QoS) features to ensure Voice over IP (VoIP) calls are prioritized over data traffic.

Basic Internet connections, on the other hand, don’t support QoS and are not four-nines reliable; they are about two nines or 99%.  Reliability, in this context, means availability of the network and also that packets actually reach their destination without being delayed or dropped such that they impact application performance and the user experience.

The emergence of WAN virtualization technology, however, means public Internet can give MPLS a run for its money.

How is this possible?

WAN virtualization solves the Internet’s problem of network peering points becoming choke points where congestion and packet loss randomly occur, and where there is a single point of failure because there’s only one connection at each location. How? By using two or more network connections at each location and monitoring precisely the one-way performance of every path between locations.

This real-time, fine-grained information on loss, jitter, latency and congestion is used to make real-time traffic engineering decisions on a packet-by-packet basis, picking the optimal path based on current traffic conditions and the type of traffic being delivered.

Think of it as a “GPS” that guides packets via an optimal route based on real-time traffic data. Advanced solutions are packet based vs. flow based, and allow even a single TCP/IP flow to use all available bandwidth as necessary.

This effectively addresses Internet weaknesses by providing physical diversity in the first- and last-mile, and detecting and avoiding congested peering points. WAN virtualization detects and mitigates problems by moving traffic from one path to another sub-second. This is an order of magnitude faster than routing protocols can move from a broken MPLS link to a backup MPLS connection or IPSec VPN.

The result is an adaptive network where application sessions don’t break, VoIP calls don’t drop, users experience predictable performance, and IT staff sleeps soundly because a network failover works transparently and reliably.

Because Internet connections are typically faster and cheaper than MPLS circuits, WAN virtualization results in a more reliable and predictable network, as well as one with more bandwidth today -- plus the flexibility to add more circuits or leverage newer access technologies as they become available.

This flexibility allows new sites to be brought online quickly with available bandwidth options, and for the first time, gives WAN managers real leverage over their service providers. Detailed reports derived from the network’s real-time measurement data allow managers to prove if an application problem was caused by the network or not.

If you are reading this after recently signing a three-year MPLS contract, don’t despair; WAN virtualization can be used to augment existing private WANs lighting up your back-up circuits, making your connections active-active. Eventually, you can cap, reduce or eliminate MPLS at some or most of your sites.

With the increasing need for faster WANs to access centralized computing sources at private and public clouds, enterprises can’t afford to ignore connectivity costs. It appears inevitable that MPLS will ultimately succumb to Internet economics as businesses cap their spending on expensive bandwidth by adding more Internet connectivity, and in some cases, eliminating MPLS at some or all of their locations.