Where's Waldo? practical searches for stability in iBGP
نویسندگان
چکیده
What does a child’s search of a large, complex cartoon for the eponymous character (Waldo) have to do with Internet routing? Network operators also search complex datasets, but Waldo is the least of their worries. Routing oscillation is a much greater concern. Networks can be designed to avoid routing oscillation, but the approaches so far proposed unnecessarily reduce the configuration flexibility. More importantly, apparently minor changes to a configuration can lead to instability. Verification of network stability is therefore an important task, but unlike the child’s search, this problem is NP hard. Until now, no practical method was available for large networks. In this paper, we present an efficient algorithm for proving stability of iBGP, or finding the potential oscillatory modes, and demonstrate its efficacy by applying it to the iBGP configuration of a large Tier-2 AS.
منابع مشابه
Eye movement feedback fails to improve visual search performance
Many real-world searches (e.g., radiology and baggage screening) have rare targets. When targets are rare, observers perform rapid, incomplete searches, leading to higher miss rates. To improve search for rare (10% prevalence) targets, we provided eye movement feedback (EMF) to observers during their searches. Although the nature of the EMF varied across experiments, each method informed observ...
متن کاملWhere’s Waldo? How perceptual, cognitive, and emotional brain processes cooperate during learning to categorize and find desired objects in a cluttered scene
The Where's Waldo problem concerns how individuals can rapidly learn to search a scene to detect, attend, recognize, and look at a valued target object in it. This article develops the ARTSCAN Search neural model to clarify how brain mechanisms across the What and Where cortical streams are coordinated to solve the Where's Waldo problem. The What stream learns positionally-invariant object repr...
متن کاملLooking back at Waldo: oculomotor inhibition of return does not prevent return fixations.
Inhibition of Return (IOR) is a difficulty in processing stimuli presented at recently attended locations. IOR is widely believed to facilitate foraging of a visual scene by decreasing the probability that gaze will return to previously fixated locations. However, there is a lack of clear evidence in support of the foraging facilitator hypothesis during scene search. The original R. M. Klein an...
متن کاملThe Scope of the IBGP Routing Anomaly Problem
Correctness problems in the iBGP routing, the de-facto standard to spread global routing information in Autonomous Systems, are a well-known issue. Configurations may route cost-suboptimal, inconsistent, or even behave non-convergent and -deterministic. However, even if a lot of studies have shown many exemplary problematic configurations, the exact scope of the problem is largely unknown: Up t...
متن کاملWhere's Waldo? The 'decapitation gambit' and the definition of death.
The 'decapitation gambit' holds that, if physical decapitation normally entails the death of the human being, then physiological decapitation, evident in cases of total brain failure, entails the death of the human being. This argument has been challenged by Franklin Miller and Robert Truog, who argue that physical decapitation does not necessarily entail the death of human beings and that ther...
متن کامل