Ethernet, MPLS and IP dominate the WAN

Which enterprise network technologies are most common?
Over the last five years, two technologies have come to dominate fixed enterprise networks: multiprotocol label switching (MPLS) and Ethernet. Demand for both MPLS IPVPN and Ethernet services are booming. Analyst Infonetics says that worldwide Ethernet service revenue grew 33% to $12.5 billion in 2007, and IP MPLS VPN service revenue grew 20% to $13 billion; it predicts that both will grow strongly through to 2011.
What's so special about MPLS and Ethernet?
MPLS was first conceived in the late 1990s to improve the performance of IP traffic over the network. For this it uses classes of service that allow enterprises to put time-sensitive applications such as VoIP in a priority class, and batch traffic such as email in a 'best-effort' class. MPLS IP VPNs are popular with enterprises because they offer quality of service and security guarantees, and allow them to utilize a single network for all voice, video and data traffic. More recently, advances in Ethernet technology have seen it make major inroads into the enterprise WAN. The main drivers for Ethernet's popularity are: ubiquity, which makes equipment economical; flexibility, as enterprises can scale bandwidth up and down easily; and its support for IP.
Why is IP fundamental to enterprise networking?
Internet Protocol (IP) is a protocol for communicating data over a packet-switched network and is the fundamental language of Internet communications. The advantage of packet switching is that it allows multiple transmissions to share the same network, so that one 'converged' network can carry all information and services - voice, data, and video. It is simpler and more economical for a large enterprise to run operations for the entire organization on a single network. 
What is a virtual private network (VPN)?
The virtual in a VPN allows you to create a private network within a much larger network, such as the Internet or a service provider's backbone. There are two types of VPNs: trusted VPNs and secure VPNs. MPLS IP VPNs are an example of the former. They allow service providers to create virtual circuits within their IP network and sell these as VPN services. MPLS isolates the traffic streams from one another so that customers can share the same network, much like legacy ATM or Frame Relay services.
What is the difference between an access and core network?
A multi-site enterprise WAN will typically comprise an access and a core network. Also called backbones, core networks such as MPLS IP VPNs and Ethernet consist of the service providers' high-speed worldwide infrastructure, to which it provides access through a series of points-of-presence (PoP). Access networks are essentially the link between those core network PoP and the enterprise site. Network technologies used here include xDSL, T1/E1, fiber, Ethernet, ISDN, dial-up, wireless networks such as WiMax and microwave, and satellite.
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Anthony Plewes

After a Masters in Computer Science, I decided that I preferred writing about IT rather than programming. My 20-year writing career has taken me to Hong Kong and London where I've edited and written for IT, business and electronics publications. In 2002 I co-founded Futurity Media with Stewart Baines where I continue to write about a range of topics such as unified communications, cloud computing and enterprise applications.