WAN stands for A Wide Area Network, and by definition WAN consists of various network connections between multiple sites. A WAN is used to provide inter-connectivity between remote sites typically using speeds considerable less than that of wired LAN connection. Numerous WAN technologies and connectivity options exist which allow the connection of remote sites. According to WAN Definition, the WAN connects devices separated by wide areas.
WAN definition, WAN describes relation between Wide Area Network and devices. WANs are designed to:
- Operate over large geographical areas
- Allow access over serial interfaces operating at lower speeds
- Provide full-time and part-time connectivity
- Connect devices which are separated over wide, even global areas
WAN Definition describes connection between WAN devices including the following:
- Network routers, offers many services including internetworking and WAN interface ports
- LAN Switches, provides connection to WAN bandwidth for voice, data, and video communication
- Modems, that interface voice-grade services; Include channel service units/digital service units (CSU/DSU) that interface T1/E1 services; Terminal Adapters/Network Termination 1 (TA/NT1) that interface Integrated Services Digital Network (ISDN) services
- Communication servers that concentrate dial-in and dial-out user communication.
- WANs use the OSI-model layered approach for frame encapsulation just like LAN’s but mainly focused on the physical and data link layers.
WAN physical layer protocols describe how to provide electrical, mechanical, operational, and functional connections for wide-area networking services. These services are most often obtained from WAN service providers such as Regional Bell Operating Companies (RBOCs), alternate carriers, and Post, Telephone, and Telegraph (PTT) agencies.
WAN Data-Link Layer
WAN definition regarding WAN data-link protocols describe how frames are carried between systems on a single data path. They include protocols designed to operate over dedicated point-to-point, multipoint, and multi access switched services such as Frame Relay.
WAN definition also describes WAN standards, which typically describes both physical layer delivery methods and data link layer requirements including addressing and flow control encapsulation.
WAN Physical Layer
WAN definition regarding WAN physical layer describes the interface between the data terminal equipment (DTE) and the data circuit-terminating equipment (DCE). Typically, the DCE is the service provider, and the DTE is the attached device. In this model, the services offered to the DTE are made available through a modem or channel service unit/data service unit CSU.
Several physical layer standards specify this interface:
- EIA/TIA-232
- EIA/TIA-449
- V.24
- V.35
- X.21
- G.703
- EIA-530
Data Link Layer: WAN Protocols
WAN definition also describes the common data-link encapsulations associated with synchronous serial lines are listed in the graphic below:
WAN Protocols
- High-Level Data Link Control (HDLC) – HDLC is an ISO standard that might not be compatible between different. HDLC supports both point-to-point and multipoint configurations.
- Frame Relay – By using a simplified framing with no error correction mechanisms over high-quality digital facilities, Frame Relay can transmit data very rapidly, compared to these other WAN protocols.
- Point-to-Point Protocol (PPP) – Described by RFC 1661, two standards developed by the IETF. PPP contains a protocol field to identify the network-layer protocol.
- Integrated Services Digital Network (ISDN) – A set of digital services that transmits voice and data over existing phone lines.
- Data Link Layer WAN Protocols support both connectionless and connection-oriented higher layer protocols
- Share internet connection discussing the methods of sharing Internet to users
- basic routing guide
- Configure router – basic configuration of a router
- Router connection – basic knowledge of connecting the router
- Router redundancy – deployed in a mission critical WAN connection
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