18,027 research outputs found
DISCO: Distributed Multi-domain SDN Controllers
Modern multi-domain networks now span over datacenter networks, enterprise
networks, customer sites and mobile entities. Such networks are critical and,
thus, must be resilient, scalable and easily extensible. The emergence of
Software-Defined Networking (SDN) protocols, which enables to decouple the data
plane from the control plane and dynamically program the network, opens up new
ways to architect such networks. In this paper, we propose DISCO, an open and
extensible DIstributed SDN COntrol plane able to cope with the distributed and
heterogeneous nature of modern overlay networks and wide area networks. DISCO
controllers manage their own network domain and communicate with each others to
provide end-to-end network services. This communication is based on a unique
lightweight and highly manageable control channel used by agents to
self-adaptively share aggregated network-wide information. We implemented DISCO
on top of the Floodlight OpenFlow controller and the AMQP protocol. We
demonstrated how DISCO's control plane dynamically adapts to heterogeneous
network topologies while being resilient enough to survive to disruptions and
attacks and providing classic functionalities such as end-point migration and
network-wide traffic engineering. The experimentation results we present are
organized around three use cases: inter-domain topology disruption, end-to-end
priority service request and virtual machine migration
A File System Abstraction for Sense and Respond Systems
The heterogeneity and resource constraints of sense-and-respond systems pose
significant challenges to system and application development. In this paper, we
present a flexible, intuitive file system abstraction for organizing and
managing sense-and-respond systems based on the Plan 9 design principles. A key
feature of this abstraction is the ability to support multiple views of the
system via filesystem namespaces. Constructed logical views present an
application-specific representation of the network, thus enabling high-level
programming of the network. Concurrently, structural views of the network
enable resource-efficient planning and execution of tasks. We present and
motivate the design using several examples, outline research challenges and our
research plan to address them, and describe the current state of
implementation.Comment: 6 pages, 3 figures Workshop on End-to-End, Sense-and-Respond Systems,
Applications, and Services In conjunction with MobiSys '0
PaRiS: Causally Consistent Transactions with Non-blocking Reads and Partial Replication
Geo-replicated data platforms are at the backbone of several large-scale
online services. Transactional Causal Consistency (TCC) is an attractive
consistency level for building such platforms. TCC avoids many anomalies of
eventual consistency, eschews the synchronization costs of strong consistency,
and supports interactive read-write transactions. Partial replication is
another attractive design choice for building geo-replicated platforms, as it
increases the storage capacity and reduces update propagation costs. This paper
presents PaRiS, the first TCC system that supports partial replication and
implements non-blocking parallel read operations, whose latency is paramount
for the performance of read-intensive applications. PaRiS relies on a novel
protocol to track dependencies, called Universal Stable Time (UST). By means of
a lightweight background gossip process, UST identifies a snapshot of the data
that has been installed by every DC in the system. Hence, transactions can
consistently read from such a snapshot on any server in any replication site
without having to block. Moreover, PaRiS requires only one timestamp to track
dependencies and define transactional snapshots, thereby achieving resource
efficiency and scalability. We evaluate PaRiS on a large-scale AWS deployment
composed of up to 10 replication sites. We show that PaRiS scales well with the
number of DCs and partitions, while being able to handle larger data-sets than
existing solutions that assume full replication. We also demonstrate a
performance gain of non-blocking reads vs. a blocking alternative (up to 1.47x
higher throughput with 5.91x lower latency for read-dominated workloads and up
to 1.46x higher throughput with 20.56x lower latency for write-heavy
workloads)
Using the Java Media Framework to build Adaptive Groupware Applications
Realtime audio and video conferencing has not yet been satisfactorily integrated into web-based groupware environments. Conferencing tools are at best only loosely linked to other parts of a shared working environment, and this is in part due to their implications for resource allocation and management. The Java Media Framework offers a promising means of redressing this situation. This paper describes an architecture for integrating the management of video and audio conferences into the resource allocation mechanism of an existing web-based groupware framework. The issue of adaptation is discussed and a means of initialising multimedia session parameters based on predicted QoS is described
The Performance of a Second Generation Service Discovery Protocol In Response to Message Loss
We analyze the behavior of FRODO, a second generation service discovery protocol, in response to message loss in the network. Earlier protocols, like UPnP and Jini rely on underlying network layers to enhance their failure recovery. A comparison with UPnP and Jini shows that FRODO performs more efficiently in maintaining consistency, with shorter latency, not relying on lower network layers for robustness and therefore functions correctly on a simple lightweight protocol stack
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