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WAN Emulation - Testing Network Applications Using WAN Emulators
WAN emulation is a technique where the properties of an existing, planned and/or non-ideal network are simulated in order to assess performance, predict the impact of change, or otherwise optimize technologies choice-creating.
By: Gregg Faust
These networked applications are now core to many of the things every computer user does every day - simple things like accessing bank accounts online, accessing emails & calendars, booking travel tickets, social networking, (Facebook), and smart phone applications. They also can be found in processes such as controlling traffic lights and operating modern IP based public CCTV.
There is a whole world of difference between how an application runs in the LAN and how it runs in the WAN, Satellite, Mobile 3G/GPRS etc., which cannot be simply resolved by increasing the available bandwidth.
WAN emulation can be accomplished by introducing a device on the LAN that alters packet flow in a way that imitates the behavior of application visitors in the environment being emulated. This device might be either a general-purpose personal computer running software to perform the network emulation or a dedicated emulation device. The device incorporates a variety of network attributes into its emulation model - such as the round-trip time across the network (latency), the quantity of available bandwidth, a given degree of packet loss, duplication of packets, reordering packets, and/or the severity of network jitter. Desktop PCs can be connected to the emulated environment, so that users can encounter the performance and behavior of applications in that environment initial-hand. Similarly, phones can be connected to the emulated environment so that users can directly assess VoIP call quality for themselves.
WAN Emulation differs from simulation in that a network emulator appears to be a network end-systems such as computers can be attached to the emulator and will behave as if they are attached to a network. Network simulators are usually programs which run on a single pc, take an abstract description of the network traffic (such as a flow arrival method) and yield performance statistics (such as buffer occupancy as a function of time).
A network emulator emulates the network which connects end-systems, not the end-systems themselves. Systems which emulate the end-systems are called visitors generators.
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Since 1983, Tredent Data Systems (TDS) has been providing solutions for data communications needs. Started in 1983 by John and Gloria Tredent, TDS provided growing companies with ways to connect remote locations back to their headquarters.
The needs of companies to connect each remote location back to corporate, whether its retail stores, manufacturing, or just a remote presence in a different state or country, allowed TDS to grow into one of the nations most successful WAN integration companies. ??With the advent of the Internet in the mid 90’s, the ease and possibilities of accessing huge amounts of data, took data communications to another level.