Using a private wide-area network (WAN)
When the open internet proves too unreliable in terms of latency, jitter, packet loss, or path convergence, the historical answer has been for companies to build a private WAN using MPLS.
Multiprotocol Label Switching (MPLS)
Whereas IP routing operates at Layer 3 of the OSI model, MPLS operates below that (often called Layer 2.5). Data is forwarded based on labels along predetermined paths, which allows MPLS to offer far more reliable packet delivery than IP routing over the internet can.
The trouble with MPLS is bandwidth cost. Because many organizations do not have the capital required to deploy their own global MPLS network, paying an ISP or telco for a slice of theirs is common. However, this is quite expensive. For reference, 1 Gbps of business-class internet access from an ISP in New York City might cost $500/month. 1 Gbps of MPLS service in the same city could easily cost $100,000/month. This is why MPLS tends to be purchased...
