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Deployment and maintenance of current data center networks is costly and prone to errors. In order to avoid manual configuration, many of them require centralized administrators which constitute a clear bottleneck, while distributed approaches do not guarantee sufficient flexibility or robustness. This paper describes and evaluates GA3 (Generalized Automatic Address Assignment), a discovery protocol that assigns multiple unique labels to all the switches in a hierarchical network, without any modification of hosts or the standard Ethernet frames. Labeling is distributed and uses probes. These labels can be leveraged for shortest path routing without tables, as in the case of the Torii protocol, but GA3 also allows other label-based routing protocols (such as PortLand or ALIAS). Additionally, GA3 can detect miswirings in the network. Furthermore, control traffic is only necessary upon network deployment rather than periodically. Simulation results showed a reduced convergence time of less than 2 s and 100 kB/s of bandwidth (to send the GA3 frames) in the worst case for popular data center topologies, which outperforms other similar protocols., Comunidad de Madrid

This paper describes and evaluates Torii, a layer 2 data centre network fabric protocol. The main features of Torii are being fully distributed, scalable, fault-tolerant and with automatic setup. Torii is based on multiple, tree-based, topological media access control addresses that are used for table-free forwarding over multiple equal-cost paths, and it is capable of rerouting frames around failed links on the fly without needing a central fabric manager for any function. To the best of our knowledge, it is the first protocol that does not require the exchange of periodic messages to work under normal conditions and to recover from link failures, as Torii exchanges messages just once. Moreover, another important characteristic of Torii is that it is compatible with a wide range of data centre topologies. Simulation results show an excellent distribution of traffic load and latencies, similar to the shortest path protocols. Copyright © 2014 John Wiley & Sons, Ltd.

Today, link-state routing protocols that compute multiple shortest paths predominate in data center and campus networks, where routing is performed either in layer three or in layer two using link-state routing protocols. But current proposals based on link-state routing do not adapt well to real time traffic variations and become very complex when attempting to balance the traffic load. We propose All-Path bridging, an evolution of the classical transparent bridging that forwards frames over shortest paths using the complete network topology, which overcomes the limitations of the spanning tree protocol. All-Path is a new frame routing paradigm based on the simultaneous exploration of all paths of the real network by a broadcast probe frame, instead of computing routes on the network graph. This paper presents All- Path switches and their differences with standard switches and describes ARP-Path protocol in detail, its path recovery mechanisms and compatibility with IEEE 802.1 standard bridges. ARP-Path is the first protocol variant of the All-Path protocol family. ARP-Path reuses the standard ARP Request and Reply packets to explore reactively the network and find the fastest path between two hosts. We compare its performance in terms of latency and load distribution with link-state shortest-path routing bridges, showing that ARP-Path distributes the load more evenly and provides lower latencies. Implementations on different platforms prove the robustness of the protocol. The conclusion is that All-Path bridging offer a simple, resilient and scalable alternative to path computation protocols., Comunidad de Madrid

This paper describes Path-Moose, a scalable tree-based shortest path bridging protocol. Both ARP-Path and Path-Moose protocols belong to a new category of bridges that we name All-path, because all paths of the network are explored simultaneously with a broadcast frame distributed over all network links to find a path or set a multicast tree. Path-Moose employs the ARP-based low latency routing mechanism of the ARP-Path protocol on a bridge basis instead of a per-single-host basis. This increases scalability by reducing forwarding table entries at core bridges by a factor of fifteen times for big data center networks and achieves a faster reconfiguration by an approximate factor of ten. Reconfiguration time is significantly shorter than ARP-Path (zero in many cases) because, due to the sharing of network paths by the hosts connected to same edge bridges, when a host needs the path it has already been recovered by another user of the path. Evaluation through simulations shows protocol correctness and confirms the theoretical evaluation results. This work was supported in part by grants from Comunidad de Madrid and Universidad de Alcal´a through the following projects: MEDIANET-CM (S-2009/TIC-468), EMARECE (PII1I09-0204-4319) and CMAC (UAH2011/EXP-016). Publicado

The work at: The 37th IEEE Conference on Local Computer Networks (LCN). Clearwater, Florida, USA. Date: 22-25 October 2012 This paper describes Flow-Path, an AllPath flowbased switching protocol that features improved load adaptive properties. Upon arrival of a new flow to the network, it explores every possible path reaching from source to destination host and selects the lowest latency path at the moment. It is based on the same basic principle than ARPPath, that is, snooping the ARP protocol dialog (request and reply messages) to explore all available paths at the same time that address resolution takes place, but it is flow-based instead of source address-based. While preserving the main advantages of ARP-Path: shortest path bridging exploiting the full network topology, Flow-Path has the advantages of full independence of flows at the time of path creation and guarantees path symmetry (congruency) and increased path diversity. Flow-Path thus improves load distribution, at the expense of increased address table size in each bridge. This work was supported in part by grants from Comunidad de Madrid and Comunidad de Castilla-La Mancha through Projects MEDIANET-CM (S-2009/TIC- 1468) and EMARECE (PII1I09-0204-4319). Publicado

2011 IEEE 12th International Conference on High Performance Switching and Routing took place July 4-6, 2011 in Cartagena, Spain. This event web site is: http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5976787 This paper describes the implementation of ARPPath (a.k.a. FastPath) bridges, a recently proposed concept for low latency bridges, in Linux/Soekris and OpenFlow/NetFPGA platforms. These ARP-based Ethernet Switches rely on the race between the replicas of a standard ARP Request packet flooded over all links, to discover the minimum latency path to the destination host, complemented in the opposite direction by the ARP Reply packet directed to the source host. Implementations show that the protocol is loop free, does not block links, is fully transparent to hosts and neither needs a spanning tree protocol to prevent loops nor a link state protocol to obtain low latency paths. Implementations in Linux and OpenFlow on NetFPGA show inherent robustness and fast reconfiguration. Previous simulations showed a superior performance (throughput and delay) than the Spanning Tree Protocol and similar to shortest path routing, with lower complexity This work was supported in part by grants from Comunidad de Madrid and Comunidad de Castilla la Mancha through Projects MEDIANET-CM (S-2009/TIC-1468), EMARECE (PII1I09-0204-4319) and T2C2(TIN2008-06739-C04-04). Publicado

This article describes a scalable, self-configuring architecture for campus networks, the ABridges architecture. It is a two-tiered hierarchy of layer two switches in which network islands running independent rapid spanning tree protocols communicate through a core formed by island root bridges (ABridges). ABridges use AMSTP, a simplified and self configuring version of MSTP protocol, to establish shortest paths in the core using multiple spanning tree instances, one instance rooted at each core edge ABridge. The architecture is very efficient in terms of network usage and path length due to the ability of AMSTP to provide optimum paths in the core mesh, while RSTP is used to aggregate efficiently the traffic at islands networks, where sparsely connected, tree-like topologies are frequent and recommended. Convergence speed is as fast as existing Rapid Spanning Tree and Multiple Spanning Tree Protocols. Publicado