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Talks, student talks, and other events of 2018

Monday, 12. February 2018

Impact of active probing on 802.11 performance
Speaker:
Marcin Bosk (TU Berlin bachelor student)
Type:
Bachelorstudent final talk
Time:
12 February 2018
15:30–16:00
Place:
MAR 4.033
Abstract:
Wireless networks play a significant role in today’s Internet access scheme. Because many devices such as Laptops, Smartphones and Tablets rely on them, it is important to keep performance of these networks at the highest level and give users the best throughput achievable. Some devices also feature more than one local interface that connects them to the Internet. A choice needs to be made which is the most optimal to use. Such decision requires some operational facts about these interfaces. A way to obtain that information and focus of this thesis is the active probing (scanning) in IEEE 802.11 networks. It can be utilized to acquire information from the access point about the parameters and usage of the wireless channel it operates on. Active probing introduces overhead in the medium, it being a trade-off for information obtained about the wireless link. In this thesis we show the influence active probing has on a device that performs such scanning. To accomplish that, a test set-up consisting of a single access point and one station associated with it is utilized. Using this arrangement, we analyze the frames present on the wireless channel under various data traffic conditions and probing schemes. The scans are being requested by Multiple Access Manager (MAM), a part of the Socket Intents Framework implementation. We conclude that active probing has a significant impact on the IEEE 802.11 network. The medium is notably less utilized and the throughput achievable using WiFi is lowered by 30% to 50% depending on the test scenario, compared to tests with no scanning. Later, we also investigate other ways the end devices can acquire information from the access points. We focus on passive scanning again based on the example of Multiple Access Manager. In this work we rewrite MAM to use a monitor interface which obtains the information from access points without the use of active probing. This change results in performance of the wireless network not being decreased and staying on the same level as in control tests where no scanning was done.

Friday, 09. February 2018

Realizing a Wireless Switch Abstraction in ONOS
Speaker:
Arne Kappen (TU Berlin bachelor student)
Type:
Bachelorstudent final talk
Time:
09 February 2018
13:00–13:30
Place:
MAR 4.033
Abstract:
The the need for bandwidth and availability of wireless access networks is increasing since ever modern mobile end device is WiFi enabled. Denser and larger WiFi deployments require novel means of network management and control to ensure an efficient use of the available wireless resources. Here, centralized control promises better decision-making from the vantage point of a unified network view.
In this talk, we present a wireless switch abstraction realized in ONOS and an integrated Open Source wireless Software-Defined Networking (SDN) implementation for OpenWRT/LEDE-based WiFi access points. We leverage SDN techniques to consolidate the state of all the wireless access points in a logically centralized control plane. This control plane hides the network complexity and exposes a unified network view. Moreover, it provides an interface to monitor and control the network elements performing split-MAC functionality. Through measurements, we show that our proposed solution handles well the expected load of standard WiFi network deployments. We understand our work as an enabler for more advanced applications. During the design of our system, we focused on extensibility and the possibility to incorporate new functionality at a later stage.
 

Thursday, 11. January 2018

Masterstudent introductory talk
Speaker:
Martin Ott
Type:
Masterstudent introductory talk
Time:
11 January 2018
16:00–16:30
Place:
MAR 4.023

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