Metro networks link local switching central offices in a large metropolis. These days there are two types of metro networks: those grown from traditional telephone networks and those that have been built by nontraditional telecoms companies for different plans.
National agencies that have changes of telephone lines branch out to individual customers. And a metro rail network connects all central offices largely in a metropolitan area like San Francisco or NewYork. The part of the network from the center to the customer is the "access network", while the interior is home to the "underground network".
A large underground network you can use two layers of network loops. The inner layer, called "U-Bahn-access loops" that connect groups of central offices, and this in cycles, which in turn link to a "metro-core network loop that connects the city all together. In short, it seems a big circle with smaller circlesinside.
:: How can customers leasing capacity in metro networks?
The owners of these metropolitan networks, often the ability to hire in bulk to other companies. Examples: company, telephone connections between their central offices, phone companies, large private companies leased lines, or even competitive phone companies that have their own networks.
We see here an example. A cable company can lease capacity from local TV stations andThe headquarters of the cable companies. So the local television station may report directly to the cable company and give them a very clean signal for distribution through its cable network.
Another example might be the cable company to lease capacity from an antenna on a farm on the outskirts of the seat. So be obtained from the satellite signals from the antenna farm, directly to the cable company signals that the quality 'and speed of delivery will be sent guaranteed.
:: WhatYou can rent the capacity of an underground network?
Most of the new metro network transfers offer a very high-speed service for lease. The capacity can of 155Mbit / s to 10 Gbit / s. Alternatively you can also rent an entire channel in the link fiber optic transmission and run independently choose.
:: How can you access a network, U-Bahn
Two types of access to the underground network available: a hub or an add-drop multiplexer.
A hub is a point where it will disable all signals in the systemand organized. The hubs are local central offices.
An add-drop multiplexer is a point where some signals get picked up and dropped another. An add-drop multiplexer directs only a portion of the signals at nodes.
:: U-Bahn network transmission links
Metro system, transmission range of a few kilometers can range up to 200 km, but most are shorter in the field. Most fields are actually below 100 km and therefore no longer required in optical amplifiersWhere the coupling losses are too high.
Does not require optical amplifier light wavelength can operate outside of readily available bandwidth optical amplifier. These wavelengths of light are the transmitter and can spread on a wider range of cheaper optics.
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