A Wide Area Network (WAN) is a computer network deployed to exchange data over wide geographical area. A WAN is usually bigger than a LAN and makes use of phone lines or satellites for transmitting data. WANs are used to connect LANs and other types of networks and they are usually built with leased lines. They can also be implemented by utilising circuit switching or packet switching methods. Service providers use protocols such as Packet over SONET/SDH, MPLS, ATM and Frame Relay to offer the links that are used in WANs.
Originally designed as switching technology Gigabit Ethernet makes use of fibre or copper for connections. It is said to be an extension of 10 Mbps Ethernet networking standard, 10Base-T, and the 100 Mbps fast Ethernet standards, 100Base-TX and 100Base-FX. The new 10 Gigabit Ethernet or 10 GbE or 10 GibE standard is claimed to be the fastest of the Ethernet standards and is capable of transmitting data rates at 10 Gbps speeds.
Ethernet can be deployed with fibre, copper or even wireless media and IEEE standards such as 802.1q and 802.1p have only made the Ethernet more robust and resilient. Ethernet is said to be one of the main causes for the explosive growth of the Internet and its high speed transport capability has helped in the evolution of advanced services such as high-definition video, on-demand, media sharing and many more.
SONET and ATM have vast and advantageous features that help in the deployment of WAN. SONET (Synchronous Optical Network) is deployed in the network because of its rich features. It offers high speed connectivity and high availability and can support data transfer rates ranging from 1.5 Mbps to 45 Mbps.
ATM (Asynchronous Transfer Mode) enhances utilisation and quality of service on high-traffic networks. ATM networks can transfer data at the speed of 155 Mbps and are also capable of reaching speeds up to 622 Mbps.
Deploying Gigabit Ethernet is claimed to be cost-effective over SONET and ATM and its support for high speed data rates enables providers to satisfy their WAN transport requirements and at the same time reduce their costs and increase their revenue.
Some of the advantages of Ethernet are that is a cost effective solution that allows incremental investments which in turn will help increase the ROI. It supports data intensive applications such as video conferencing and complex imaging by increasing the MAC (Machine Access Control) layer data rates.
Both SONET and ATM which are time-division multiplexing (TDM) based infrastructure were designed for low level data transfer services. These are the two protocols that are widely used in implementing WAN networks. Even though they offer high multiplexing efficiency, high availability and reliability they incur high infrastructure costs at every site they are deployed. This cost is said to be caused by their requirement to terminate two large trunk interfaces, the need for redundant STS-1/STM-1 switch fabrics capable of handling the trunk interfaces at every site, and the complex protocol adaptation of all client signals to the rigid requirements of the SONET architecture.
On the other hand Gigabit Ethernet which can be very easily integrated into existing Ethernet infrastructure has the capability to retain the simplicity and manageability of Ethernet and Fast Ethernet.
For example, if an organisation decides to expand the reach of its WAN network i.e. annex nearby buildings or areas into one single network, by deploying Ethernet WAN it can easily achieve this objective. Gigabit Ethernet is claimed to be the ideal choice for transferring IP data because of its ability to support fibre spans of more than 70 km.
The advantage of packet based networks is that entire network topology uses the same technology which removes the latency involved in protocol conversion at each end of the circuit as in the case of SONET or ATM. Also in Ethernet topology data is converted into IP packets and it traverses the network in the form of Ethernet frames consistently throughout the entire transmission path which removes the need for additional layers of protocols and synchronisation that only results in extra costs and complexities.
Companies can choose either the copper line or the fibre line to deploy the Ethernet WAN. Copper is ideal for data transmission over shorter distances whereas fibre is more suited to transmit data over long distances. Ethernet services can be offered via multi-pair telephone cabling by bringing together newer modulation technologies and multi-twisted copper pair. The telephone cabling is the same one installed in almost all the business buildings eliminating the need for laying newer lines. This significantly brings down the construction costs.
Carriers by deploying a Gigabit Ethernet over fibre connection can offer Ethernet WAN bandwidth at a much lower price than other technologies.
Ethernet with its technical simplicity, lower cost and fast provisioning abilities is far more advantageous than SONET/SDH in deploying a WAN.