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Devoflow: Scaling flow management for high-performance networks
- In ACM SIGCOMM
, 2011
"... OpenFlow is a great concept, but its original design imposes excessive overheads. It can simplify network and traffic management in enterprise and data center environments, because it enables flow-level control over Ethernet switching and provides global visibility of the flows in the network. Howev ..."
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Cited by 134 (1 self)
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OpenFlow is a great concept, but its original design imposes excessive overheads. It can simplify network and traffic management in enterprise and data center environments, because it enables flow-level control over Ethernet switching and provides global visibility of the flows in the network. However, such fine-grained control and visibility comes with costs: the switch-implementation costs of involving the switch’s control-plane too often and the distributed-system costs of involving the OpenFlow controller too frequently, both on flow setups and especially for statistics-gathering. In this paper, we analyze these overheads, and show that OpenFlow’s current design cannot meet the needs of highperformance networks. We design and evaluate DevoFlow, a modification of the OpenFlow model which gently breaks the coupling between control and global visibility, in a way that maintains a useful amount of visibility without imposing unnecessary costs. We evaluate DevoFlow through simulations, and find that it can load-balance data center traffic as well as fine-grained solutions, without as much overhead: DevoFlow uses 10–53 times fewer flow table entries at an average switch, and uses 10–42 times fewer control messages.
Where is the Debugger for my Software-Defined Network?
"... These authors contributed equally to this work The behavior of a Software-Defined Network is controlled by programs, which like all software, will have bugs – but this programmatic control also enables new ways to debug networks. This paper introduces ndb, a prototype network debugger inspired by gd ..."
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Cited by 50 (4 self)
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These authors contributed equally to this work The behavior of a Software-Defined Network is controlled by programs, which like all software, will have bugs – but this programmatic control also enables new ways to debug networks. This paper introduces ndb, a prototype network debugger inspired by gdb, which implements two primitives useful for debugging an SDN: breakpoints and packet backtraces. We show how ndb modifies forwarding state and logs packet digests to rebuild the sequence of events leading to an errant packet, providing SDN programmers and operators with a valuable tool for tracking down the root cause of a bug.
Kandoo: A Framework for Efficient and Scalable Offloading of Control Applications
"... Limiting the overhead of frequent events on the control plane is essential for realizing a scalable Software-Defined Network. One way of limiting this overhead is to process frequent events in the data plane. This requires modifying switches and comes at the cost of visibility in the control plane. ..."
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Cited by 39 (0 self)
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Limiting the overhead of frequent events on the control plane is essential for realizing a scalable Software-Defined Network. One way of limiting this overhead is to process frequent events in the data plane. This requires modifying switches and comes at the cost of visibility in the control plane. Taking an alternative route, we propose Kandoo, a framework for preserving scalability without changing switches. Kandoo has two layers of controllers: (i) the bottom layer is a group of controllers with no interconnection, and no knowledge of the network-wide state, and (ii) the top layer is a logically centralized controller that maintains the network-wide state. Controllers at the bottom layer run only local control applications (i.e., applications that can function using the state of a single switch) near datapaths. These controllers handle most of the frequent events and effectively shield the top layer. Kandoo’s design enables network operators to replicate local controllers on demand and relieve the load on the top layer, which is the only potential bottleneck in terms of scalability. Our evaluations show that a network controlled by Kandoo has an order of magnitude lower control channel consumption compared to normal OpenFlow networks.
Logically Centralized? State Distribution Trade-offs in Software Defined Networks
"... Software Defined Networks (SDN) give network designers freedom to refactor the network control plane. One core benefit of SDN is that it enables the network control logic to be designed and operated on a global network view, as though it were a centralized application, rather than a distributed syst ..."
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Cited by 25 (2 self)
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Software Defined Networks (SDN) give network designers freedom to refactor the network control plane. One core benefit of SDN is that it enables the network control logic to be designed and operated on a global network view, as though it were a centralized application, rather than a distributed system – logically centralized. Regardless of this abstraction, control plane state and logic must inevitably be physically distributed to achieve responsiveness, reliability, and scalability goals. Consequently, we ask: “How does distributed SDN state impact the performance of a logically centralized control application?” Motivated by this question, we characterize the state exchange points in a distributed SDN control plane and identify two key state distribution trade-offs. We simulate these exchange points in the context of an existing SDN load balancer application. We evaluate the impact of inconsistent global network view on load balancer performance and compare different state management approaches. Our results suggest that SDN control state inconsistency significantly degrades performance of logically centralized control applications agnostic to the underlying state distribution.
Software-Defined Networking: A Comprehensive Survey
, 2014
"... The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to pre- ..."
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Cited by 20 (3 self)
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The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to pre-defined policies, and to reconfigure it to respond to faults, load and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-Defined Networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network’s control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns introduced between the definition of network policies, their
Towards an Elastic Distributed SDN Controller
"... Distributed controllers have been proposed for Software Defined Networking to address the issues of scalability and reliability that a centralized controller suffers from. One key limitation of the distributed controllers is that the mapping between a switch and a controller is statically configured ..."
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Cited by 17 (2 self)
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Distributed controllers have been proposed for Software Defined Networking to address the issues of scalability and reliability that a centralized controller suffers from. One key limitation of the distributed controllers is that the mapping between a switch and a controller is statically configured, which may result in uneven load distribution among the controllers. To address this problem, we propose ElastiCon, an elastic distributed controller architecture in which the controller pool is dynamically grown or shrunk according to traffic conditions and the load is dynamically shifted across controllers. We propose a novel switch migration protocol for enabling such load shifting, which conforms with the Openflow standard. We also build a prototype to demonstrate the efficacy of our design.
AVANT-GUARD: Scalable and Vigilant Switch Flow Management in Software-Defined Networks
"... Among the leading reference implementations of the Software De-fined Networking (SDN) paradigm is the OpenFlow framework, which decouples the control plane into a centralized application. In this paper, we consider two aspects of OpenFlow that pose secu-rity challenges, and we propose two solutions ..."
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Cited by 17 (5 self)
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Among the leading reference implementations of the Software De-fined Networking (SDN) paradigm is the OpenFlow framework, which decouples the control plane into a centralized application. In this paper, we consider two aspects of OpenFlow that pose secu-rity challenges, and we propose two solutions that could address these concerns. The first challenge is the inherent communication bottleneck that arises between the data plane and the control plane, which an adversary could exploit by mounting a control plane sat-uration attack that disrupts network operations. Indeed, even well-mined adversarial models, such as scanning or denial-of-service (DoS) activity, can produce more potent impacts on OpenFlow net-works than traditional networks. To address this challenge, we in-troduce an extension to the OpenFlow data plane called connec-tion migration, which dramatically reduces the amount of data-to-control-plane interactions that arise during such attacks. The second challenge is that of enabling the control plane to expedite both detection of, and responses to, the changing flow dynamics within the data plane. For this, we introduce actuating triggers over the data plane’s existing statistics collection services. These triggers are inserted by control layer applications to both register for asynchronous call backs, and insert conditional flow rules that are only activated when a trigger condition is detected within the data plane’s statistics module. We present AVANT-GUARD, an im-plementation of our two data plane extensions, evaluate the perfor-mance impact, and examine its use for developing more scalable and resilient SDN security services.
A Survey of Software-Defined Networking: Past, Present, and Future of Programmable Networks
, 2013
"... The idea of programmable networks has recently re-gained considerable momentum due to the emergence of the Software-Defined Networking (SDN) paradigm. SDN, often referred to as a “radical new idea in networking”, promises to dramatically simplify network management and enable in-novation through net ..."
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Cited by 16 (2 self)
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The idea of programmable networks has recently re-gained considerable momentum due to the emergence of the Software-Defined Networking (SDN) paradigm. SDN, often referred to as a “radical new idea in networking”, promises to dramatically simplify network management and enable in-novation through network programmability. This paper surveys the state-of-the-art in programmable networks with an emphasis on SDN. We provide a historic perspective of programmable networks from early ideas to recent developments. Then we present the SDN architecture and the OpenFlow standard in particular, discuss current alternatives for implementation and testing of SDN-based protocols and services, examine current and future SDN applications, and explore promising research directions based on the SDN paradigm.
Driving software defined networks with xsp
- In SDNŠ12: Workshop on Software Defined Networks
, 2012
"... Abstract—This paper presents the eXtensible Session Protocol (XSP), which provides a control plane for driv-ing Software Defined Networks (SDNs). The XSP model supports proactive, application-driven configuration of dy-namic network resources with support for authentication and authorization, within ..."
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Cited by 8 (1 self)
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Abstract—This paper presents the eXtensible Session Protocol (XSP), which provides a control plane for driv-ing Software Defined Networks (SDNs). The XSP model supports proactive, application-driven configuration of dy-namic network resources with support for authentication and authorization, within an extensible protocol frame-work. We describe XSP application use cases in SDNs using OpenFlow enabled network devices as well as dynamic forwarding rule management that can be implemented on existing router platforms. I.
PolicyCop: An Autonomic QoS Policy Enforcement Framework for Software Defined Networks
"... Abstract—Network management is becoming increas-ingly challenging with the relentless growth in network size, traffic volume, and the diversity in QoS requirements. Traditionally, the concept of predefined Service Level Agreements (SLAs) has been utilized to establish QoS parameters. However, state- ..."
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Cited by 7 (3 self)
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Abstract—Network management is becoming increas-ingly challenging with the relentless growth in network size, traffic volume, and the diversity in QoS requirements. Traditionally, the concept of predefined Service Level Agreements (SLAs) has been utilized to establish QoS parameters. However, state-of-the-art technologies in this area are both proprietary and inflexible. To this end, Software Defined Networking (SDN) has the potential to make network management tasks flexible and scalable, and to provide an open platform to encourage innovation. In this paper, we present PolicyCop – an open, flexible, and vendor agnostic QoS policy management framework targeted towards OpenFlow based SDN. PolicyCop pro-vides an interface for specifying QoS-based SLAs and enforces them using the OpenFlow API. It monitors the network and autonomically readjusts network parameters to satisfy customer SLAs. We present experimental re-sults to demonstrate PolicyCop’s effectiveness in ensuring throughput, latency, and reliability guarantees. I.
