Multi-Protocol Label Switching promises a number of new efficiencies and control features for service providers. The benefits of MPLS have certainly been noticed, as the technology is widely adopted within telecom networks. So what are some of those MPLS benefits?
Lower Cost
MPLS is a layer 2.5 technology. It allows shared network resources, but private routing for customers’ data.
“It has some of the scalability and cost advantages that Layer 3 public Internet has, but it also has some additional security and some efficiencies that make it really good for deploying these large-scale, IP-based but protocol-agnostic, and much more private type of network services,” said Eric Bozich, vice president of marketing for CenturyLink’s wholesale division.
Quality of Service Attributes
One of the oft-cited benefits of MPLS is the ability to assign QoS features to traffic. Because MPLS works with a system of labels, customers can determine prioritization levels associated with those labels.
“One of the big features is the ability to manage and control QoS,” Bozich said. “So customers subscribe to various levels of bandwidth or sizes of ports, and then they get the ability to say if there is congestion on this network link, what type of traffic gets through or held up in cue for delivery later.”
Scalability
One of the benefits of MPLS is that it combines some of the qualities of physical “nailed up” circuits that were difficult and expensive to scale, with the cost-effective but relatively unpredictable nature of pure IP routing, according to Errol Binda, senior marketing director of Aviat Networks.
“When it comes to the scalability of larger or more complex networks, if you have MPLS, that allows you to do automatic configuration of the network and setting up of tunnels or label-switched paths. It’s less resource-intensive physically, to configure the circuits,” he said.
In addition, another MPLS benefit is its protocol-agnostic nature. Many different types of traffic can be carried via MPLS routing without regard to what type of traffic it is.
“It’s a great generalized transport,” said Joe Whitehouse of Metro Switch. “It can transport anything. A lot of the mobile backhaul networks have different types of traffic they have to transport. With 2G, there may be some TDM. With 3G, ATM, and with 4G, more IP-based [traffic]. A lot of those are co-located, and they have to take all that traffic and move it.”
Traffic Routing
MPLS works by imposing labels on packets as they leave a customer’s network and enter the MPLS network. Rather than look up IP header information to direct packets, network elements simply read the MPLS label and whisk the packet along to the next hop in a pre-determined path.
“With MPLS, you have a much more determined path from point A to point B through the network,” said Joe Whitehouse, director of marketing for the network technologies division at MetroSwitch, a major MPLS provider to OEMs.
Other benefits of MPLS include greater reliability and predictability of traffic within the network. Because the Label Switched Paths (LSPs) are pre-determined, packets only travel along the paths they have been directed upon. This is a marked difference from IP routing, where one packet’s path could be distinctly different from the next based on network conditions at the time.
“It’s almost like on every hop of the way, that router is making a decision based on what he knows for a path forward,” said Whitehouse. Where as within MPLS, he added, “it’s always down the same path and it makes life much easier for the MPLS device, which may be a router. … There’s really no heavy lifting that has to be done from an IP look-up standpoint.”
Whitehouse also noted MPLS’ ability to set up pre-programmed fallback paths, in case the typical LSP is down.
“In the case of a network failure, you can switch over the entire path to avoid the failure,” he said. “You really can’t do that with IP.”
