Networks at the speed of light
In recent years, networked computers have gained importance in the development of the activities of most of the institutions that focus on high productivity and sharing applications, especially in the field of databases and Internet functions. This short presentation tries to explain the basics on the two most common technologies used in the networks in our country: Networks Ethernet and Fast Ethernet. Ethernet and Fast Ethernet technologies have design rules that must be observed to function correctly. Maximum number of nodules and the repeaters and maximum distances segment are defined by constructive mechanical and electrical properties of each type of medium Ethernet and Fast Ethernet. For example, a network using repeaters has restrictions due to time constraints of Ethernet. Although electrical signals in an Ethernet environment have nearly the speed of light, yet it takes a while for the signal to get from one end to another in a large Ethernet network. Standard Ethernet supposed to last about 50 microseconds for a signal to reach their destination.
If the network does not respect the terms of construction the number of repeaters, then this time constraint will not be respected, and the transmission station will resend the packet, will not receive a confirmation signal of the package that you sent. This could result in loss of data packets, excessive numbers of returned packages, which can worsen and network performance can be problematic application. Ethernet applies the rule “5-4-3” placement of repeater: network can only have 5 segments connected. You can only use four repeaters. 5 segments, only three users can attach. The other two must be inter-repeaters. Fast Ethernet repeater rule has changed since the minimum size packets require less time than the Ethernet transmission. The length and standard network connections allow a smaller number of repeaters. When conditions require a greater distance or a greater number of nodes, you can use a bridge, a router or a switch to connect multiple networks together. In essence, these components assemble two separate networks, allowing network constructive reuse criteria. With switches, network designers can build extensive networks that work best.
The first servers printers support printing via serial or parallel ports, accepting one or two protocols. The latest generation of servers printer supports multiple protocols, have multiple parallel or serial connections and, in some cases, are small enough to be placed at the parallel printer port. Some printers have built-in printer server, facilitating communication between the printer and server, but decreasing degree of flexibility if the printer has physical problems. Printer servers do not have much memory as they need not only to store simple information about the host and the protocol used. When the selected printer becomes available, then allow hostname to send data to the nearest port of the server. Printer server can then analyze the queue and can print each job in ordirea that was sought, taking into account the protocol and the size of the job. Printer server allows printers in various distribution nodes throughout the network. He accepts commands from any node listing the network using protocols supporting and managing both work tiparire.Suporta parallel interface, and serial (sometimes both).