Cisco Systems RJ-45-to-AUX manual Peer−to−Peer Networking Model

Many different types of physical cable media have been introduced over the years, such as Token Ring, FDDI, and Ethernet. At one time, Token Ring was seen as a technically superior product and a viable alternative to Ethernet. Many networks still contain Token Ring, but very few new Token Ring installations are being implemented. One reason is that Token Ring is an IBM product with very little support from other vendors. Also, the prices of Token Ring networks are substantially higher than those of Ethernet networks.

FDDI networks share some of the limitations of Token Ring. Like Token Ring, FDDI offers excellent benefits in the area of high−speed performance and redundancy. Unfortunately, however, it has the same high equipment and installation costs. More vendors are beginning to recognize FDDI and are offering support, services, and installation for it—especially for network backbones.

Network backbones are generally high−speed links running between segments of the network. Normally, backbone cable links run between two routers; but they can also be found between two switches or a switch and a router.

Ethernet has by far overwhelmed the market and obtained the highest market share. Ethernet networks are open−standards based, more cost−effective than other types of physical media, and have a large base of vendors that supply the different Ethernet products. The biggest benefit that makes Ethernet so popular is the large number of technical professionals who understand how to implement and support it.

Early networks were modeled on the peer−to−peer networking model. These worked well for the small number of nodes, but as networks grew they evolved into the client/server network model of today. Let’s take a look at these two models in more depth.

Peer−to−Peer Networking Model

A small, flat network or LAN often contains multiple segments connected with hubs, bridges, and repeaters. This is an Open Systems Interconnection (OSI) Reference Model Layer 2 network that can actually be connected to a router for access to a WAN connection. In this topology, every network node sees the conversations of every other network node.

In terms of scalability, the peer−to−peer networking model has some major limitations—especially with the technologies that companies must utilize to stay ahead in their particular fields. No quality of service, prioritizing of data, redundant links, or data security can be implemented here, other than encryption. Every node sees every packet on the network. The hub merely forwards the data it receives out of every port, as shown in Figure 1.1.

Figure 1.1: A flat network topology.

Early networks consisted of a single LAN with a number of workstations running peer−to−peer networks and sharing files, printers, and other resources. Peer−to−peer networks share data with one another in a non−centralized fashion and can span only a very limited area, such as a room or building.

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