In this world, there is a growing world, people are constantly using communication between people and devices in new and different ways. Some communication types have been familiar with, such as IP voice (VoIP), digital images, multicast, video on demand, peer-to-peer file sharing, remote video conferencing, and more. However, all of these applications have a common feature: the demand for network bandwidth can be described with the word "greed".
In the long run, the bandwidth itself is always not enough. The smart "device" - switches and routers behind the network infrastructure must assume a difficult task that follows the bandwidth requirements in intelligent ways. Applications such as video and digital X-rays are always required, more intelligent "pipes", while VoIP applications require low delay and consistent transmission rates. In the mid-1990s, as the traditional switch did not fall, people began to compete for the faster, higher intelligence, and higher intelligence. A group of genius in Silicon Valley saw this market opportunity, invented the network hardware and compatible software on a new concept called "multi-layer exchange routing". These new "intelligent" switch / routers can provide faster speed and shorter delay compared to the software-based router, while capable of combining multiple network devices.
Historically, when the demand for network bandwidth increases, network administrators are redesigned by redesigning the network to avoid router bottlenecks. The server often bypasses the router and is reinstalled to where the user is closer. For example, a group of stock trading workstations may be far from other devices of the company and put together with servers that provide real-time data entries. This is because the smaller number of devices that share network resources (such as routers), the more bandwidths that can be obtained each device. Traditionally, the closer from the user and the data, the faster the speed they get data, because this avoids the generating router bottleneck.
In large enterprises, users are divided into smaller networks (subnets) that enable interconnection through the router. The foundation of user division is usually the type of region, the application type, the required amount of data and security. For example, the accounting department is often placed in their own group so that the company's financial records can be protected instead of because of their bandwidth. VoIP phones are often placed in their own network so they can bypass the bottleneck of the traditional router.
When the computer needs to communicate with other computers that are not in your local network, they send packets to their nearest routers. The router provides the connection and security boundaries between the company and the Internet, as well as the connection between the company's internal groups (internal network).
Traditional routers are only used when absolutely necessary, such as through WAN connecting a remote office, connecting to the Internet and quarantine, high bandwidth requirements. The traditional router is very expensive (now still this), and there is no significant progress compared to the original design, and the components used are similar to a standard PC and use multiple interface cards to run dedicated software.
In contrast, multi-layer exchange routers focus all of these features on a dedicated special application integrated circuit or ASIC. The ASIC is cheap than the CPU of the traditional router, and is usually distributed on the network port. Today, a typical switch / router may include 50 ASICs in a single device, which can support hundreds of interfaces. New ASIC allows smart switch / routers to forward data at very fast speed on all ports - no matter what type of network traffic. They forward traffic in actual interface speed (often referred to as linear speed). Now, the new switch / router provided by the Enterprise Local Area Network (LAN) can forward traffic at a single interface with a bandwidth (OC-192) per second.
