Friday, January 15, 2010

Is Voice Over MPLS The New PSTN?

It’s clear that packet switched networks are taking over from circuit switched networks. So much so, that the FCC is considering pulling the plug on the PSTN (Public Switched Telephone Network) at some point. It’s a clear omen that the end is near for the telephone system that has served us for over a century. But what will take its place? Will it be VoIP? How about cellular?

MPLS networks offer global private voice and data transport.It’s likely that VoIP is going to be the answer, but not the VoIP that we know today. What VoIP has going for it is established standards for coding & decoding, signaling, and a packet protocol that is compatible with Ethernet data networks. What’s holding it back from taking over virally is a wide variety of incompatible implementations, fear by wireless carriers that it will bring down their networks, and unpredictable voice quality on the Internet.

That hasn’t stopped major organizations from switching to enterprise VoIP solutions. They avoid the problems that consumers face using Voice over the Internet by rigidly controlling the performance of their in-house networks. For calls that need to go outside the organization, enterprise users will terminate outside calls to the PSTN through ISDN PRI digital trunks or have a third party SIP trunking provider terminate the calls.

Clearly, the larger the organization, the higher the percentage of calls that can be kept in-house. When companies have multiple locations, they have a decision to make. Each location can have its own PBX telephone system and connect to the PSTN for calls leaving the building. Or, a corporate PBX telephone system can handle all facilities with private trunk lines running between locations.

Chances are that a multi-location business needs data connectivity between locations anyway. So, adding voice packets to the data stream makes sense. That way call quality can be assured while avoiding the per-minute costs of using the public telephone system. The question is what type of network will work best for this application.

MPLS is increasingly becoming the network architecture of choice for converged voice and data networks. MPLS or Multi-Protocol Label Switching is designed from the ground up to handle whatever protocol you want to transport. But even if everything is IP, MPLS has some big advantages over rolling your own network with private lines.

MPLS are privately operated and available only to customers of the service. That gives the network operators the ability to ensure the availability of enough bandwidth to prevent congestion and the resulting latencies and dropped packets that slow data and destroy voice services. QoS or Quality of Service control ensure that voice packets get the priority treatment they need to maintain high audio quality.

MPLS networks are also mesh networks, which makes them ideal for interconnecting multiple business locations. You can do this yourself with a hub and spoke arrangement with headquarters at the hub and routing traffic among the other locations. But your costs will be higher and the latency between locations greater when everything has to go through a central routing hub on private point to point trunk lines.

MPLS makes so much sense that the large telecom carriers are converting their core networks to MPLS to handle today’s traffic and whatever will be coming through the pipes tomorrow. Data, voice and video are handled equally well and can be transported in traditional TDM channel as well as packet protocols. What we call the PSTN today may well become interconnected MPLS networks in the future.

In the meantime, you can be enjoying the quality, security and cost advantages that MPLS networks have to offer. Learn how MPLS for VoIP networks can work for your organization.

Click to check pricing and features or get support from a Telarus product specialist.

Follow Telexplainer on Twitter