This work introduces the concept of critical sections for online first person shooter games (FPS). A critical section is a section of game-play which demands higher precision or tighter deadlines. Critical section traffic is more sensitive to network degradations than sections immediately preceding or following it. Critical sections provide game developers and network programmers a notion of relative priority of game traffic, and can identify segments whose preservation can lead to superior user perceived quality of playing FPS games on a network. By analyzing video-recordings of over 5 hours of FPS gameplay by 10 volunteers, we identify sections of FPS game-play whose degradation would cause inconsistent game-state updates resulting in user frustration. We observe that critical sections exhibit a pattern of occurrence and can account for upto 17% of game-play time. We next quantify the expected network induced degradations on critical sections for online FPS games on the Internet. Using traces from a deployment of FPS workloads on 50+ nodes in the Internet, we study network dynamics and their ensuing effect on critical sections. Using traces from this experiment, we derive the lower bound on potentially degraded game-play session on todays Internet. We argue that critical sections of FPS games can be preserved. This can allow a variety of network architectures to better deliver higher perceptual experience when deployed on the Internet. Overall, our results have implications for FPS game-design, network provisioning, and game quality evaluation.

Internet eXchange Points (IXPs) have been recently identified as critical components of the Internet's AS level infrastructure. Recent studies have characterized the importance of IXPs in Internet topology evolution studies but the network benefits brought about by the increased peering has not garnered much attention. In this work, we propose and implement a measurement framework to compare paths traversing an IXP hop with a set of valid alternate paths which isolate the IXP effects. Our framework enables identification of these alternate paths and then carries out an in-depth comparison of the IXP path with its available alternates. Using the popular route performance metric of end- to-end latency we observe that most paths through peering ASes at exchanges generally have a better alternate through transit providers of the peering ASes. Traditional overlay routes such as detour paths also outperform the default BGP path through an IXP. While economic benefits are the primary driving forces behind public peering we conclude that obtaining network benefits (in terms of path latencies) require due consideration by peering ASes to ensure better end-user experience.

The Internet ecosystem comprising of thousands of Autonomous Systems (ASes) now include Internet eXchange Points (IXPs) as another critical component in the infrastructure. With the growth of peering worldwide, IXPs are playing an increasing role not only in the topology evolution of the Internet but also inter-domain path routing. In this work, we first motivate the need to monitor popular exchange points based on geographical locations. These major IXPs are responsible for transmitting 43% of the total IXP traffic and hence play a significant role in determining the effects of peering at IXPs on path latencies. Using the most important route performance metric of end to end latency we then propose and implement a measurement framework to carry out an in-depth comparison of paths traversing an IXP with other available alternate paths. We observe the presence of a significant percentage of alternate paths outperforming the default route through an IXP in all major regions. Even though IXPs are set up primarily with economic benefits in mind, we conclude that there is a huge potential for improvement with more efficient routing and better planning at the primary IXPs around the world.

The Internet is a network of Autonomous Systems (ASes) comprising of a complex and complicated ecosystem of net- works used for a wide variety of applications. ASes exhibit varied functionality and communicate according to predefined rules to maintain distinct business objectives; termed intra- AS relations. These relations are one of two types: customer- provider (hierarchical) or peering (flat). Recent studies of intra-AS relations indicate the gradual transition of the In- ternet ecosystem from the hierarchical structure to a flatter peering architecture [1]. This infrastructure level flattening is characterized by the constant growth, rewiring and deaths of inter-AS links. Primary driving forces behind these changes are economic; especially the meteoric rise in popularity of organizations such as Facebook, Google, Yahoo and Microsoft, who have lately deployed large, private WAN infrastructures [1]. The transition from the hierarchical Internet has also accelerated with the deployment of multiple Internet eXchange Points (IXPs) worldwide, the facilitator of peering. Numerous peering links (between ASes) at these IXPs have recently been uncovered but their effects on Internet topology and inter- domain routing performance not yet examined. Exchange points (shown in fig 1) provide an infrastructure for ASes to set up mutually agreeable peering agreements at a common location and enable the quick exchange of traffic without requiring higher tier transit providers. They also facilitate dynamic changing of peering agreements be- tween Internet Service Providers (ISPs) providing transit to customer ASes. These customer ASes obtain better network performance (lesser delays, more reliability) while the ISPs save substantially on transit costs.

The recent uncovering of a high number of peering links at Internet eXchange Point (IXP) locations across the world has made these exchange switches a critical component of the Internet Autonomous System (AS) level ecosystem. Studies concentrating on the Internet topology evolution have surmised that numerous links hidden at these exchange points hold the key towards solving the missing links problem in studying the evolution of the AS-level topology of the Internet. In this work, we study the effect of this set of hitherto unseen peering links on the visible Internet topology. Starting from a simple visual analysis and continuing with a more advanced graph based metric analysis, we conclude that IXP links follow power law increase characteristics while exhibiting definitive clustering characteristics. Moreover, these additional links affect the joint degree distributions of nodes with higher degrees while leaving most other types of nodes unchanged. We conclude that the currently inferred AS-level maps of the Internet demonstrate considerable variations with the incorporation of these new links and could eventually provide us a better understanding of Internet topology evolution.