{"title":"Congestion management for non-blocking clos networks","authors":"Nikolaos Chrysos","doi":"10.1145/1323548.1323569","DOIUrl":"https://doi.org/10.1145/1323548.1323569","url":null,"abstract":"We propose a distributed congestion management scheme for non-blocking, 3-stage Clos networks, comprising plain buffered crossbar switches. VOQ requests are routed using multipath routing to the switching elements of the 3rd-stage, and grants travel back to the linecards the other way around. The fabric elements contain independent single-resource schedulers, that serve requests and grants in a pipeline. As any other network with limited capacity, this scheduling network may suffer from oversubscribed links, hotspot contention, etc., which we identify and tackle. We also reduce the cost of internal buffers, by reducing the data RTT, and by allowing sub-RTT crosspoint buffers. Performance simulations demonstrate that, with almost all outputs congested, packets destined to non-congested outputs experience very low delays ( ow isolation). For applications requiring very low communication delays, we propose a second, parallel operation mode, wherein linecards can forward a few packets eagerly, each, bypassing the request-grant latency overhead.","PeriodicalId":329300,"journal":{"name":"Symposium on Architectures for Networking and Communications Systems","volume":"31 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126305248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Sushanth Kumar, M. Becchi, P. Crowley, J. Turner
{"title":"CAMP: fast and efficient IP lookup architecture","authors":"S. Sushanth Kumar, M. Becchi, P. Crowley, J. Turner","doi":"10.1145/1185347.1185355","DOIUrl":"https://doi.org/10.1145/1185347.1185355","url":null,"abstract":"A large body of research literature has focused on improving the performance of longest prefix match IP-lookup. More recently, embedded memory based architectures have been proposed, which delivers very high lookup and update throughput. These architectures often use a pipeline of embedded memories, where each stage stores a single or set of levels of the lookup trie. A stream of lookup requests are issued into the pipeline, one every cycle, in order to achieve high throughput. Most recently, Baboescu et al. [21] have proposed a novel architecture, which uses circular memory pipeline and dynamically maps parts of the lookup trie to different stages.In this paper we extend this approach with an architecture called Circular, Adaptive and Monotonic Pipeline (CAMP), which is based upon the key observation that circular pipeline allows decoupling the number of pipeline stages from the number of levels in the trie. This provides much more flexibility in mapping nodes of the lookup trie to the stages. The flexibility, in turn, improves the memory utilization and also reduces the total memory and power consumption. The flexibility comes at a cost however; since the requests are issued at an arbitrary stage, they may get blocked if their entry stage is busy. In an extreme case, a request may block for a time equal to the pipeline depth, which may severely affect the pipeline utilization. We show that fairly straightforward techniques can ensure nearly full utilization of the pipeline. These techniques, coupled with an adaptive mapping of trie nodes to the circular pipeline, create a pipelined architecture which can operate at high rates irrespective of the trie size.","PeriodicalId":329300,"journal":{"name":"Symposium on Architectures for Networking and Communications Systems","volume":"44 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121002570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}