A single user with a slow connection to a wireless network can significantly degrade the overall service to everyone using that wi-fi access station, new research shows.
Researchers from the Institut d鈥橧nformatique et Math茅matiques Appliqu茅es de Grenoble, part of France鈥檚 CNRS, studied the performance of networks using the popular wi-fi standard 802.11b.
They found that if a single user鈥檚 connection is slowed, perhaps because they are far from the access station, every user can suffer reduced data transfer speeds. 鈥淭hat computer may degrade the nominal bit rate,鈥� Duda told 快猫短视频.
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This is because of the way bandwidth is allocated to each user by the wi-fi standard鈥檚 access protocol, called Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA).
If just one person is unable to connect at the optimal speed, the CSMA/CA protocol throttles back the maximum connection speed for all. This guarantees that any user, no matter what their access speed, can get stable access to the network.
If the faster users were not limited and the network approached its maximum bandwidth, the slower user鈥檚 service would be the first to degrade to the point of uselessness. However, the speed limit could mean that the best connected users see their transfer speeds cut from 11 Mb per second to about 1 Mb/s.
Duda says users may not notice a network snarl-up unless they are using a lot of bandwidth by, for example, downloading large files. And he adds that some manufacturers have already begun to address the issue with their latest wireless networking hardware.
But it is particularly important, he says, that devices using the newer and higher-bandwidth networking standards such as 802.11g do not suffer from the same problem.
鈥淚n general, designers should be aware of this problem,鈥� says Mingyan Liu, a wireless networking expert at the University of Michigan in the US. He says it is a question of balancing the stability of the network for all with the quality of service delivered to the majority of users.
鈥淏ut it would be worthwhile for researchers and engineers to come up with mitigating methods,鈥� Lui told 快猫短视频.