optical NW
equipment costs [1]
fiber medium
switching costs
duct costs
[1]
The network topology is the basic graph structure of a network consisting of nodes and edges that provide direct connections between two locations
Many properties of a transport network ultimately depend on the topology. In order to reduce costs, it is essential to consider all relevant aspects when allocating physical edges. This task is not only important when building up a transport network from scratch, which is often called “green field” planning. Instead, reconsidering the network topology is also involved when a network needs to be upgraded to support new traffic demands or quality of service. The provisioning expenses of a dense physical topology are high because of excavation costs and the procurement of rights-of-way.On the other hand, a well connected network can reduce capacity requirements as short transmission paths can be found between the nodes. Additionally, dense networks are crucial when ensuring resilience against multiple failures. We investigate these characteristics in order to find an optimal topology. {intro}
v.i protection path
backup path
restoration
green failed P3 vi
this work is a novel investigation of optimal topological design using the combined consideration of multiple failures and total network costs including capacity expenses plus topology costs.
[1]
[2]operational system of many other sectors of our economy, such that when the infrastructure is damaged or its fails as a result of cut on the physical layer vital communication links to airline industry (e.g. airport), health service (e.g. emergency services), power industry (e.g. nuclear power facility), banking industry (e.g. mobile financial services) etc. are interrupted.
OPTICAL FIBER NETWORK INFRASTRUCTURE IMPLEMENTATION METHODS[2]
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Underground Optical Cable Installation
Arial or Overhead Installation
Direct Burial Installation
indirect Burial Installation
Submarine Installation
[3] multilongitudinal mode (MLM)////leds
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In this case, the distance limitation was primarily due to a phenomenon known as intermodal dispersion. As we saw earlier, in a multimode fiber the energy in a pulse travels in different modes, each with a different speed. At the end of the fiber, the different modes arrive at slightly different times, resulting in a smearing of the pulse.
At this point another impairment, namely, chromatic dispersion, started becoming a limiting factor as far as increasing the bit rates was concerned. Chromatic dispersion is another form of dispersion in optical fiber (we looked at intermodal dispersion earlier). As we saw earlier, the energy in a light signal or pulse has a finite bandwidth. Even in a single-mode fiber, the different frequency components of a pulse propagate with different speeds. This is due to the fundamental physical properties of the glass.
The erbium atoms in the fiber are pumped from their ground state to an excited state at a higher energy level using a pump source. An incoming signal photon triggers these atoms to come down to their ground state. In the process, each atom emits a photon. Thus incoming signal photons trigger the emission of additional photons, resulting in optical amplification.
There are several types of nonlinear effects that occur in optical fiber. One of them is called four-wave mixing (FWM). In FWM, three light signals at different wavelengths interact in the fiber to create a fourth light signal at a wavelength that may overlap with one of the light signals. As we can imagine, this signal interferes with the actual data that is being transmitted on that wavelength.
[3]OPTICAL FIBER COMMUNICATION:
FROM TRANSMISSION TO NETWORKING
Centralization, which is a key characteristic of a network, can be used to measurenetwork robustness as the differences between the centrality of the most central node and that of all others [21]. In general, the most central network is the most robust i.e. if the network has more nodes with similar centrality values, there are then several spots to attack when centrality metrics are used to select the elements to be removed.
[4] Robustness Comparison of 15 Real Telecommunication
Networks: Structural and Centrality Measurements
Taxonomy of Robustness Metrics
Structural Metrics
Centrality Metrics
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degree centrality
,closeness centrality,
spreaders
eigenvector centrality,
betweenness centrality
Functional Metrics
To achieve some minimum level of robustness, a backbone network must not break in case of a single node or link failure, i.e., it must be biconnected. If such condition is not satisfied, as it is the case of REUNA network, link(s) must be added to the topology until achieve that.
[5]Measuring and Improving Network Robustness: A Chilean Case Study
from this paper we can do biconnected by multiway to get rebetness but we have to chooce the best way
pre-strategy