Network tomography is the study of a
network's internal characteristics using information derived from end point data. The word
tomography is used to link the field, in concept, to other processes that infer the internal characteristics of an object from external observation, as is done in
MRI or
PET scanning (even though the term
tomography strictly refers to imaging by slicing). The field is a recent development in
electrical engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
and
computer science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...
, dating from 1996. Network tomography seeks to map the path data takes through the
Internet
The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...
by examining information from “edge nodes,” the computers in which the data are originated and from which they are requested.
The field is useful for engineers attempting to develop more efficient computer networks. Data derived from network tomography studies can be used to increase
quality of service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...
by limiting link
packet loss
Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is either caused by errors in data transmission, typically across wireless networks, or network congestion.Ku ...
and increasing
routing
Routing is the process of selecting a path for traffic in a Network theory, network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched ...
optimization.
Recent developments
There have been many published papers and tools in the area of network tomography, which aim to monitor the health of various links in a network in real-time. These can be classified into loss and delay tomography.
Loss tomography
Loss tomography aims to find “lossy” links in a network by sending active “probes” from various vantage points in the network or the Internet.
Delay tomography
The area of delay tomography has also attracted attention in the recent past. It aims to find link delays using end-to-end probes sent from vantage points. This can potentially help isolate links with large queueing delays caused by
congestion.
More applications
Network tomography may be able to infer
network topology
Network topology is the arrangement of the elements (Data link, links, Node (networking), nodes, etc.) of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, ...
using end-to-end probes. Topology discovery is a tradeoff between accuracy vs. overhead. With network tomography, the emphasis is to achieve as accurate a picture of the network with minimal overhead. In comparison, other network topology discovery techniques using
SNMP or
route analytics
Network monitoring is the use of a system that constantly monitors a computer network for slow or failing components and that notifies the network administrator (via email, SMS or other alarms) in case of outages or other trouble. Network monito ...
aim for greater accuracy with less emphasis on overhead reduction.
Network tomography may find links which are shared by multiple paths (and can thus become potential bottlenecks in the future).
Network Tomography may improve the control of a
smart grid
The smart grid is an enhancement of the 20th century electrical grid, using two-way communications and distributed so-called intelligent devices. Two-way flows of electricity and information could improve the delivery network. Research is main ...
See also
*
Network science
Network science is an academic field which studies complex networks such as telecommunication networks, computer networks, biological networks, Cognitive network, cognitive and semantic networks, and social networks, considering distinct eleme ...
*
Computer network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...
References
{{DEFAULTSORT:Network Tomography
Networks
Electrical engineering