328 research outputs found
Impact of path diversity on multi-homed and overlay networks
Multi-homed and overlay networks are two widely stud-ied approaches aimed at leveraging the inherent redun-dancy of the Internet’s underlying routing infrastructure to enhance end-to-end application performance and availabil-ity. However, the effectiveness of these approaches depends on the natural diversity of redundant paths between two endhosts in terms of physical links, routing infrastructure, administrative control and geographical distribution. This paper quantitatively analyzes the impact of path diversity on multi-homed and overlay networks and highlights sev-eral inherent limitations of these architectures in exploit-ing the full potential redundancy of the Internet. We based our analysis on traceroutes and routing table data collected from several vantage points in the Internet including: look-ing glasses at ten major Internet Service Providers (ISPs), RouteViews servers from twenty ISPs, and more than fifty PlanetLab nodes globally distributed across the Internet. Our study motivates new research directions—constructing topology-aware multi-homing and overlay networks for bet-ter availability.
Endpoint-transparent Multipath Transport with Software-defined Networks
Multipath forwarding consists of using multiple paths simultaneously to
transport data over the network. While most such techniques require endpoint
modifications, we investigate how multipath forwarding can be done inside the
network, transparently to endpoint hosts. With such a network-centric approach,
packet reordering becomes a critical issue as it may cause critical performance
degradation.
We present a Software Defined Network architecture which automatically sets
up multipath forwarding, including solutions for reordering and performance
improvement, both at the sending side through multipath scheduling algorithms,
and the receiver side, by resequencing out-of-order packets in a dedicated
in-network buffer.
We implemented a prototype with commonly available technology and evaluated
it in both emulated and real networks. Our results show consistent throughput
improvements, thanks to the use of aggregated path capacity. We give
comparisons to Multipath TCP, where we show our approach can achieve a similar
performance while offering the advantage of endpoint transparency
Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections
Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay networ
SDN based testbeds for evaluating and promoting multipath TCP
Multipath TCP is an experimental transport proto-
col with remarkable recent past and non-negligible future poten-
tial. It has been standardized recently, however the evaluation
studies focus only on a limited set of isolated use-cases and
a comprehensive analysis or a feasible path of Internet-wide
adoption is still missing. This is mostly because in the current
networking practice it is unusual to configure multiple paths
between the endpoints of a connection. Therefore, conducting and
precisely controlling multipath experiments over the real “inter-
net” is a challenging task for some experimenters and impossible
for others. In this paper, we invoke SDN technology to make
this control possible and exploit large-scale internet testbeds to
conduct end-to-end MPTCP experiments. More specifically, we
establish a special purpose control and measurement framework
on top of two distinct internet testbeds. First, using the OpenFlow
support of GÉANT, we build a testbed enabling measurements
with real traffic. Second, we design and establish a publicly
available large-scale multipath capable measurement framework
on top of PlanetLab Europe and show the challenges of such
a system. Furthermore, we present measurements results with
MPTCP in both testbeds to get insight into its behavior in such
not well explored environment
Low latency via redundancy
Low latency is critical for interactive networked applications. But while we
know how to scale systems to increase capacity, reducing latency --- especially
the tail of the latency distribution --- can be much more difficult. In this
paper, we argue that the use of redundancy is an effective way to convert extra
capacity into reduced latency. By initiating redundant operations across
diverse resources and using the first result which completes, redundancy
improves a system's latency even under exceptional conditions. We study the
tradeoff with added system utilization, characterizing the situations in which
replicating all tasks reduces mean latency. We then demonstrate empirically
that replicating all operations can result in significant mean and tail latency
reduction in real-world systems including DNS queries, database servers, and
packet forwarding within networks
MPTCP Robustness Against Large-Scale Man-in-the-Middle Attacks
International audienceMultipath communications at the Internet scale have been a myth for a long time, with no actual protocol being deployed at large scale. Recently, the Multipath Transmission Control Protocol (MPTCP) extension was standardized and is undergoing rapid adoption in many different use-cases, from mobile to fixed access networks, from data-centers to core networks. Among its major benefits-i.e., reliability thanks to backup path rerouting, through-put increase thanks to link aggregation, and confidentiality being more difficult to intercept a full connection-the latter has attracted lower attention. How effective would be to use MPTCP, or an equivalent multipath transport layer protocol, to exploit multiple Internet-scale paths and decrease the probability of Man-in-the-Middle (MITM) attacks is a question which we try to answer. By analyzing the Autonomous System (AS) level graph, we identify which countries and regions show a higher level of robustness against MITM AS-level attacks, for example due to core cable tapping or route hijacking practices.
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