WAN Technology: Circuit, Message & Frame Relay
WAN Technology: Understanding the Basics
WANs (Wide Area Networks) can cover distances from approximately 100 km to over 1000 km, providing service to a country or continent. Many WANs, such as RedIRIS or those used by Internet providers, are built by private companies for private use, offering high-speed connectivity.
Typically, a WAN is a point-to-point network. WANs may use satellite communication systems or radio technology. Their primary function is networking, connecting terminal equipment located at great distances from each other. This requires an infrastructure based on powerful switching nodes that interconnect these elements and handle a significant, continuous flow of information. These connections, often called “channels” or “trunks,” move information between different network nodes.
Circuit Leasing Services
Point-to-point circuits enable the transmission of voice and/or data between two fixed points. This is especially beneficial when the volume of information is very high (justifying a flat fee) or when the points are relatively close. Compared to other solutions, leased lines can be very advantageous.
Circuit Switching
Circuit switching involves establishing a physical circuit *before* information is sent. This circuit remains open for the entire duration of the transmission. The physical path is chosen from available options, using various signaling techniques to establish, maintain, and release the circuit. An example of this type of network is the PSTN (Public Switched Telephone Network).
Message Switching
Message switching is a method based on processing units of information. Each unit is equipped with a source address and a destination address. This allows it to be processed by switching centers in the network, which store the message until they can verify its successful delivery.
Frame Relay Technology
Frame Relay is a technology that transmits “frames” of data of various sizes, making it ideal for transmitting large amounts of technical data. The Frame Relay service is used for high-speed voice and data transmission, allowing the interconnection of geographically separated local area networks (LANs) at a lower cost.
Initially, Frame Relay was an economical alternative to dedicated lines. It established point-to-point communications between two remote locations without the high cost of a dedicated line. Because Frame Relay is not dedicated, customers share the same wires and facilities, with each having assigned virtual circuits (VCs).
Frame Relay provides connections between users via a public network, similar to a point-to-point private network. This means it is connection-oriented. Connections can be permanent (Permanent Virtual Circuit or PVC) or switched (Switched Virtual Circuit or SVC). Currently, only permanent connections are commonly used. A significant advantage is its ability to replace multiple private lines with a single network link.
Applications and Benefits of Frame Relay
- Reduced Network Complexity: Multiple virtual connections can share the same access line.
- Lower Equipment Costs: Reduces hardware needs and simplified processing offers better performance for the cost.
- Improved Performance and Response Time: Direct connectivity between areas with minimal network delays.
- Increased Network Availability: Network connections can be automatically redirected to different paths when an error occurs (e.g., Telefónica’s CVP Plus service, a backup PVC that activates upon primary CVP failure).
- Flat Fee Pricing: Prices are not distance-sensitive, meaning customers are not penalized for long-distance connections.