30,905 research outputs found
CASPR: Judiciously Using the Cloud for Wide-Area Packet Recovery
We revisit a classic networking problem -- how to recover from lost packets
in the best-effort Internet. We propose CASPR, a system that judiciously
leverages the cloud to recover from lost or delayed packets. CASPR supplements
and protects best-effort connections by sending a small number of coded packets
along the highly reliable but expensive cloud paths. When receivers detect
packet loss, they recover packets with the help of the nearby data center, not
the sender, thus providing quick and reliable packet recovery for
latency-sensitive applications. Using a prototype implementation and its
deployment on the public cloud and the PlanetLab testbed, we quantify the
benefits of CASPR in providing fast, cost effective packet recovery. Using
controlled experiments, we also explore how these benefits translate into
improvements up and down the network stack
Shortcuts through Colocation Facilities
Network overlays, running on top of the existing Internet substrate, are of
perennial value to Internet end-users in the context of, e.g., real-time
applications. Such overlays can employ traffic relays to yield path latencies
lower than the direct paths, a phenomenon known as Triangle Inequality
Violation (TIV). Past studies identify the opportunities of reducing latency
using TIVs. However, they do not investigate the gains of strategically
selecting relays in Colocation Facilities (Colos). In this work, we answer the
following questions: (i) how Colo-hosted relays compare with other relays as
well as with the direct Internet, in terms of latency (RTT) reductions; (ii)
what are the best locations for placing the relays to yield these reductions.
To this end, we conduct a large-scale one-month measurement of inter-domain
paths between RIPE Atlas (RA) nodes as endpoints, located at eyeball networks.
We employ as relays Planetlab nodes, other RA nodes, and machines in Colos. We
examine the RTTs of the overlay paths obtained via the selected relays, as well
as the direct paths. We find that Colo-based relays perform the best and can
achieve latency reductions against direct paths, ranging from a few to 100s of
milliseconds, in 76% of the total cases; 75% (58% of total cases) of these
reductions require only 10 relays in 6 large Colos.Comment: In Proceedings of the ACM Internet Measurement Conference (IMC '17),
London, GB, 201
Re-designing Dynamic Content Delivery in the Light of a Virtualized Infrastructure
We explore the opportunities and design options enabled by novel SDN and NFV
technologies, by re-designing a dynamic Content Delivery Network (CDN) service.
Our system, named MOSTO, provides performance levels comparable to that of a
regular CDN, but does not require the deployment of a large distributed
infrastructure. In the process of designing the system, we identify relevant
functions that could be integrated in the future Internet infrastructure. Such
functions greatly simplify the design and effectiveness of services such as
MOSTO. We demonstrate our system using a mixture of simulation, emulation,
testbed experiments and by realizing a proof-of-concept deployment in a
planet-wide commercial cloud system.Comment: Extended version of the paper accepted for publication in JSAC
special issue on Emerging Technologies in Software-Driven Communication -
November 201
Datacenter Traffic Control: Understanding Techniques and Trade-offs
Datacenters provide cost-effective and flexible access to scalable compute
and storage resources necessary for today's cloud computing needs. A typical
datacenter is made up of thousands of servers connected with a large network
and usually managed by one operator. To provide quality access to the variety
of applications and services hosted on datacenters and maximize performance, it
deems necessary to use datacenter networks effectively and efficiently.
Datacenter traffic is often a mix of several classes with different priorities
and requirements. This includes user-generated interactive traffic, traffic
with deadlines, and long-running traffic. To this end, custom transport
protocols and traffic management techniques have been developed to improve
datacenter network performance.
In this tutorial paper, we review the general architecture of datacenter
networks, various topologies proposed for them, their traffic properties,
general traffic control challenges in datacenters and general traffic control
objectives. The purpose of this paper is to bring out the important
characteristics of traffic control in datacenters and not to survey all
existing solutions (as it is virtually impossible due to massive body of
existing research). We hope to provide readers with a wide range of options and
factors while considering a variety of traffic control mechanisms. We discuss
various characteristics of datacenter traffic control including management
schemes, transmission control, traffic shaping, prioritization, load balancing,
multipathing, and traffic scheduling. Next, we point to several open challenges
as well as new and interesting networking paradigms. At the end of this paper,
we briefly review inter-datacenter networks that connect geographically
dispersed datacenters which have been receiving increasing attention recently
and pose interesting and novel research problems.Comment: Accepted for Publication in IEEE Communications Surveys and Tutorial
Software Defined Networks based Smart Grid Communication: A Comprehensive Survey
The current power grid is no longer a feasible solution due to
ever-increasing user demand of electricity, old infrastructure, and reliability
issues and thus require transformation to a better grid a.k.a., smart grid
(SG). The key features that distinguish SG from the conventional electrical
power grid are its capability to perform two-way communication, demand side
management, and real time pricing. Despite all these advantages that SG will
bring, there are certain issues which are specific to SG communication system.
For instance, network management of current SG systems is complex, time
consuming, and done manually. Moreover, SG communication (SGC) system is built
on different vendor specific devices and protocols. Therefore, the current SG
systems are not protocol independent, thus leading to interoperability issue.
Software defined network (SDN) has been proposed to monitor and manage the
communication networks globally. This article serves as a comprehensive survey
on SDN-based SGC. In this article, we first discuss taxonomy of advantages of
SDNbased SGC.We then discuss SDN-based SGC architectures, along with case
studies. Our article provides an in-depth discussion on routing schemes for
SDN-based SGC. We also provide detailed survey of security and privacy schemes
applied to SDN-based SGC. We furthermore present challenges, open issues, and
future research directions related to SDN-based SGC.Comment: Accepte
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