With the maturation of Carrier Ethernet, we are seeing operators deploy – or desire to deploy – single, converged metro networks that support multiple business, residential and mobile backhaul services and applications. But while network convergence can bring long-term capex and opex savings, it does pose issues related to complexity, capacity demands and QoS requirements. For service convergence to work cost effectively on a large scale, the complexity must be removed from the equation.
While it is technically possible to extend MPLS from the metro core into the access network to support the convergence of services, it has generally been too expensive to accomplish on a large scale due to opex and capex reasons. MPLS was developed for the IP core, and it is more suited to the operational processes and scalability requirements of this part of the network rather than transport. As a result, adopting MPLS ‘as is’ can impose steep learning curves on transport/access network managers, along with the operational models that have been developed over decades.
These operational concerns and the cost of deploying MPLS routers at every node represent significant barriers to mass adoption of the carrier-grade, all-IP metro network. Too, because of the learning curve involved with MPLS, operators often find themselves deploying a parallel IP/MPLS network managed by a separate team alongside their traditional transport network. All these complexities cancel out any savings that a truly consolidated network provides.
Fortunately, things are changing with the emergence of MPLS-TP (Multi-Protocol Label Switching Transport Profile), which was developed by the IETF and ITU. By tackling the barriers that MPLS faces when it is pushed towards the metro, MPLS-TP changes the economic equation and makes end-to-end MPLS deployment affordable via streamlined operational models and consolidated and simplified network topologies.
A key element in lowering costs and simplifying operations is management. MPLS-TP is managed through a centralized network management system (NMS) rather than a distributed control plane. Instead of having to integrate a complex and costly IP control plane into each network node, all control complexity is located at the NMS. Moreover, the same working procedures that are used today to manage transport networks can be preserved without the need to hire costly personnel who are familiar with complex IP protocols. Another cost-saving benefit is the GUI-based unified management, which simplifies service deployment via point-and-click provisioning and automated monitoring.
Overall, introducing NMS-based MPLS-TP into the metro access/aggregation network allows operators to gain control of network resources rather than relinquish it to the complex control plane.
As I mentioned earlier, MPLS was developed for the core. When it is implemented end to end, the number of nodes can increase by a factor of 100, and this can affect scalability and resiliency. MPLS-TP’s simpler OAM and transport-grade resiliency make it well suited for large networks.
As MPLS-TP continues to work its way into the feature sets of P-OTS, CESR and MSPP platforms, operators gain much-welcomed flexibility when choosing the mix of optical and Ethernet platforms that best suits their migration path to NGN.
Next time, we’ll explore some of the key applications that can benefit from MPLS-TP.