The guys at Techwise TV have a short but interesting feature on Cisco IOS
Techwise TV
Sunday 18 November 2012
Thursday 15 November 2012
SIP trunking - part 1
Recently we implemented a Vodafone SIP trunk at our office. The Vodafone setup consists of a fiberswitch and a Cisco 2901 CUBE (Cisco Unified Border Element). Normally the CUBE connects directly to a Cisco Unified Communication Manager (CUCM) but we connected it to our own CUBE mainly because of 3 reasons:
- our own CUBE enables us to control the way it talks tot the CUCM
- we need SRST on the CUBE because the SIP-trunk is not located at the CUCM-site.
- it's also the prefered way to do it
Researchers Find Way to Boost WiFi Performance 400-700 Percent
Is this just bringing switching tech to a shared medium? Nonetheless interesting:
WiFi hotspots in locations such as airports and large conventions frequently experience poor performance in terms of downlink goodput and responsiveness. We study the various factors responsible for this performance degradation. We analyse and emulate a large conference network environment on our testbed with 45 nodes. We find that presence of asymmetry between the uplink/downlink traffic results in backlogged packets at WiFi Access Point’s (AP’s) transmission queue and subsequent packet losses. This traffic asymmetry results in maximum performance loss for such an environment along with degradation due to rate diversity, fairness and TCP behavior. We propose our solution WiFox, which (1) adaptively prioritizes AP’s channel access over competing STAs avoiding traffic asymmetry (2) provides a fairness framework alleviating the problem of performance loss due to rate-diversity/fairness and (3) avoids degradation due to TCP behavior. We demonstrate that WiFox not only improves downlink goodput by 400-700 % but also reduces request’s average response time by 30-40 %.
http://news.ncsu.edu/releases/wms-gupta-wifi/
WiFi hotspots in locations such as airports and large conventions frequently experience poor performance in terms of downlink goodput and responsiveness. We study the various factors responsible for this performance degradation. We analyse and emulate a large conference network environment on our testbed with 45 nodes. We find that presence of asymmetry between the uplink/downlink traffic results in backlogged packets at WiFi Access Point’s (AP’s) transmission queue and subsequent packet losses. This traffic asymmetry results in maximum performance loss for such an environment along with degradation due to rate diversity, fairness and TCP behavior. We propose our solution WiFox, which (1) adaptively prioritizes AP’s channel access over competing STAs avoiding traffic asymmetry (2) provides a fairness framework alleviating the problem of performance loss due to rate-diversity/fairness and (3) avoids degradation due to TCP behavior. We demonstrate that WiFox not only improves downlink goodput by 400-700 % but also reduces request’s average response time by 30-40 %.
http://news.ncsu.edu/releases/wms-gupta-wifi/
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