154,639 research outputs found
Performance, Validation and Testing with the Network Simulation Cradle
Much current simulation of TCP makes use of simplified models of TCP, which is a large and complex protocol with many variations possible between implementations. We use direct execution of real world network stacks in the network simulator ns-2 to compare TCP performance between implementations and reproduce existing work. A project called The Network Simulation Cradle provides the real world network stacks and we show how it can be used for performance evaluation and validation. There are large differences in performance between simplified TCP models and TCP implementations in some situations. Such differences are apparent in some reproduced research, with results using the Network Simulation Cradle very different from the results produced with the ns-2 TCP models. In other cases, using the real implementations gives very similar results, validating the original research
A First Look at QUIC in the Wild
For the first time since the establishment of TCP and UDP, the Internet
transport layer is subject to a major change by the introduction of QUIC.
Initiated by Google in 2012, QUIC provides a reliable, connection-oriented
low-latency and fully encrypted transport. In this paper, we provide the first
broad assessment of QUIC usage in the wild. We monitor the entire IPv4 address
space since August 2016 and about 46% of the DNS namespace to detected
QUIC-capable infrastructures. Our scans show that the number of QUIC-capable
IPs has more than tripled since then to over 617.59 K. We find around 161K
domains hosted on QUIC-enabled infrastructure, but only 15K of them present
valid certificates over QUIC. Second, we analyze one year of traffic traces
provided by MAWI, one day of a major European tier-1 ISP and from a large IXP
to understand the dominance of QUIC in the Internet traffic mix. We find QUIC
to account for 2.6% to 9.1% of the current Internet traffic, depending on the
vantage point. This share is dominated by Google pushing up to 42.1% of its
traffic via QUIC
Quality of service assurance for the next generation Internet
The provisioning for multimedia applications has been of increasing interest among researchers and Internet Service Providers. Through the migration from resource-based to service-driven networks, it has become evident that the Internet model should be enhanced to provide support for a variety of differentiated services that match applications and customer requirements, and not stay limited under the flat best-effort service that is currently provided.
In this paper, we describe and critically appraise the major achievements of the efforts to introduce Quality of Service (QoS) assurance and provisioning within the Internet model. We then propose a research path for the creation of a network services management architecture,
through which we can move towards a QoS-enabled network environment, offering support for a variety of different services, based on traffic characteristics and user expectations
Gozar: NAT-friendly Peer Sampling with One-Hop Distributed NAT Traversal
Gossip-based peer sampling protocols have been widely used as a building block for many large-scale distributed applications. However, Network Address Translation gateways (NATs) cause most existing gossiping protocols to break down, as nodes cannot establish direct connections to nodes behind NATs (private nodes). In addition, most of the existing NAT traversal algorithms for establishing connectivity to private nodes rely on third party servers running at a well-known, public IP addresses. In this paper, we present Gozar, a gossip-based peer sampling service that: (i) provides uniform random samples in the presence of NATs, and (ii) enables direct connectivity to sampled nodes using a fully distributed NAT traversal service, where connection messages require only a single
hop to connect to private nodes. We show in simulation that Gozar preserves the randomness properties of a gossip-based peer sampling service. We show the robustness of Gozar when a large fraction of nodes reside behind NATs and also in
catastrophic failure scenarios. For example, if 80% of nodes are behind NATs, and 80% of the nodes fail, more than 92% of the remaining nodes stay connected. In addition, we compare Gozar with existing NAT-friendly gossip-based peer sampling services, Nylon and ARRG. We show that Gozar is the only system that supports one-hop NAT traversal, and its overhead is roughly half of Nylon’s
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