LAN network design, MAN network design and WAN network design services design and develop large-scale networks for communication providers or large-enterprise businesses. MAN network design services specialize in metropolitan area networks (MAN) that serve users in regions larger than the areas covered by local area networks (LAN), but smaller than the areas served by wide area networks (WAN). Unlike MAN and WAN networks, LANs are limited to an immediate area, such as an office building or a floor in a building. WANs cover a much broader geographic area, sometimes spanning cities, states and even countries. Whereas LAN design services support users in a relatively limited location, MAN and WAN network design services support the protocols and technologies used in these larger metropolitan area network (MAN) and wide area network (WAN) environments.
LAN network design, MAN network design and WAN network design services that support metropolitan area networks (MAN) may adhere to the IEEE 802.6 MAN standard from the Institute of Electrical and Electronics Engineers (IEEE). IEEE 802.6 MAN defines the distributed queue dual bus (DQDB) network form and supports the open systems interconnect (OSI) protocol, a communications standard that defines a networking framework with seven layers. IEEE 802.16a, an amendment to IEEE 802.16-2001, builds upon the WirelessMAN-SC air interface, a single carrier (SC) modulation scheme designed to operate in the 10 - 66 GHz spectrum. LAN, MAN and WAN network design services that adhere to IEEE 802.16a may retain the single-carrier access method for special-purpose networks, but add a 256-carrier, orthogonal frequency, division multiplexed (OFDM) layer to split the signal into smaller sub signals.
LAN network design, MAN network design and WAN network design services that support wide area networks (WAN) understand technologies that function at the lower three layers of the OSI reference model. Typically, these LAN, MAN and WAN network design services support point-to-point links, packet-switched circuits, switched circuits, virtual circuits, or circuit switching. Point-to-point links provide a single, pre-defined communications path from a customer’s premises through a carrier network to a remote network. Packet-switched circuits let users share common carrier resources via asynchronous transfer mode (ATM), frame relay, switched multi-megabit data services (SMDS), or X.25. Switched circuits initiate data connections as needed and terminate connections when communication is complete. WAN virtual circuits are created within a shared network between two networked devices, and include both switched virtual circuits (SVC) and permanent virtual circuits (PVC). Integrated services digital network (ISDN), a type of circuit switching, provides on-demand data connections.