The world is rapidly shifting to mobile applications-based communications. With the rise of high speed 4G networks, access flexibility and amazing “genius” phones and tablets this makes sense. Even if Facebook has overcome the challenge in monetizing mobile advertisements. Yet, to be prepared for a deluge of mobile devices accessing your public facing websites you need to be ready for the perils of mobile connectivity.
Since the dawn of the Internet, session interruptions have been greatly amplified for wireless users. Packets get dropped by simply walking around or sharing a congested access point. Clients experience dropped packets when switching between towers and oversubscribed networks. Unfortunately current protocol standards assume packet loss is always due to infrastructure bottlenecks and while valid for users connected to broadband networks (e.g.,DSL) this is problematic for mobile users; packet loss is due to more than congestion.
The current standard TCP implementation relies on packet loss as an indicator of network congestion. The problem is that TCP does not possess the capability to distinguish congestion loss from that invoked by noisy links. In wireless connections overlapping radio channels, signal attenuation, and additional sources of noise result in serious interruptions of service. As a consequence, standard TCP mistakenly reacts with a drastic reduction of the transmission window size. When TCP sessions lose a packet, it stops, and slowly ramps again with lower throughput over time until packet loss no longer occurs.
The solution is to this conundrum is to employ NetScaler Application Delivery Controllers (ADCs) with support for TCP Westwood (TCPW). This fully standardized and deployed TCP protocol extension works by finding the ideal performance in a mobile network and is designed to handle noisy mobile links. TCPW can tell when packet loss is due to mobility or congestion. Mobile users now obtain higher overall throughput with significant performance improvement over long distance, high bandwidth links. TCPW on NetScaler is disabled by default but can be configured in minutes.
TCP Westwood is a small modification of the standard TCP congestion and control algorithm. When the sender perceives that congestion has appeared, the sender uses the estimated available bandwidth to set the congestion window and the slow start threshold sizes. TCPW avoids huge reductions of these values and ensures both faster recovery and effective congestion avoidance. It does not require any support from lower or higher OSI layers and does not need any explicit congestion feedback from the network. TCPW ensures faster recovery and effective congestion avoidance to provide a better end user experience. Just in time to easily view more mobile client ads!