Multi-layer switching makes the router "smart"

In today's world, the network is more and more high, the communication between people and equipment with each passing day, a wide range. Some of these types of communication are well-known, such as IP voice (VoIP), digital images, multicast, video-on-demand, peer-to-peer file sharing, remote video conferencing, and so on. However, all of these applications have a common feature that the need for network bandwidth can be described as "insatiable".

In the long run, bandwidth itself is always inadequate. As a result, the smart "devices" behind the network infrastructure, that is, switches and routers, must assume the difficult task of being intelligent to keep pace with bandwidth requirements. Applications like video and digital x-rays always require a larger, smarter "transmission pipeline," While VoIP applications require low latency or response times and consistent delivery rates. In the middle of the 90, with the decline of traditional switches, people began to race to develop faster, more intelligent switches and routers. A swarm of Silicon Valley geniuses have seen this opportunity, creating network hardware and related software based on a new concept called "Multilayer switched routing". These new "smart" switches/routers provide faster speed and shorter latency than software-based routers at the time, and can combine the capabilities of multiple network devices.

Originally, when the need to increase network bandwidth, network administrators often through the network redesign to avoid bottlenecks in the router. Servers often do not go through routers and are reinstalled closer to the user. In large enterprises, users are often divided into smaller networks (subnets) that interconnect through routers. This division is usually based on geographical, operational application types, the amount of data required and security factors. For example, the Finance Department is often fully deployed in its own group, because it is designed to effectively protect the company's financial records, rather than taking into account the bandwidth used. VoIP telephony is also often placed in its own network because it bypasses the bottleneck of traditional routers.

When computers need to communicate with other computers outside their local network, in order to send packets outside the group, they must first send packets to their nearest router. Routers provide connectivity and security boundaries between the company and the Internet, as well as connections between groups within a company (intranet).

Traditional routers are used only when absolutely necessary, such as connecting remote offices over a WAN, connecting to the Internet, or isolating groups with high-bandwidth requirements in the company. Traditional routers are expensive, and still are, and there is no significant progress compared to the original design, using components similar to a standard PC and using multiple interface cards to run proprietary software.

Problem: Core router "bottleneck"

Solution: Combine network functions with multilayer switched routers

In contrast, multilayer switched routers focus all the functions of a traditional router on a dedicated integrated circuit (ASIC). The ASIC is less expensive than traditional routers and is typically distributed across multiple network ports. Today, a typical switch/router may include 50 ASIC in one device, and can support hundreds of interfaces. In addition, the new ASIC allows intelligent switches/routers to forward data at the fastest speed on all ports, regardless of the type of network traffic, which can be said to forward data at the actual interface speed (often called a wire speed). Currently, new switches/routers on the market for corporate local area networks (LANs) can forward data on a single interface with gigabit bandwidth per second (OC-192).