1,059 research outputs found
Equilibrium of Heterogeneous Congestion Control: Optimality and Stability
When heterogeneous congestion control protocols
that react to different pricing signals share the same network,
the current theory based on utility maximization fails to predict
the network behavior. The pricing signals can be different types
of signals such as packet loss, queueing delay, etc, or different
values of the same type of signal such as different ECN marking
values based on the same actual link congestion level. Unlike in a
homogeneous network, the bandwidth allocation now depends on
router parameters and flow arrival patterns. It can be non-unique,
suboptimal and unstable. In Tang et al. (“Equilibrium of heterogeneous
congestion control: Existence and uniqueness,” IEEE/ACM
Trans. Netw., vol. 15, no. 4, pp. 824–837, Aug. 2007), existence and
uniqueness of equilibrium of heterogeneous protocols are investigated.
This paper extends the study with two objectives: analyzing
the optimality and stability of such networks and designing control
schemes to improve those properties. First, we demonstrate the
intricate behavior of a heterogeneous network through simulations
and present a framework to help understand its equilibrium
properties. Second, we propose a simple source-based algorithm
to decouple bandwidth allocation from router parameters and
flow arrival patterns by only updating a linear parameter in the
sources’ algorithms on a slow timescale. It steers a network to
the unique optimal equilibrium. The scheme can be deployed
incrementally as the existing protocol needs no change and only
new protocols need to adopt the slow timescale adaptation
Agile-SD: A Linux-based TCP Congestion Control Algorithm for Supporting High-speed and Short-distance Networks
Recently, high-speed and short-distance networks are widely deployed and
their necessity is rapidly increasing everyday. This type of networks is used
in several network applications; such as Local Area Networks (LAN) and Data
Center Networks (DCN). In LANs and DCNs, high-speed and short-distance networks
are commonly deployed to connect between computing and storage elements in
order to provide rapid services. Indeed, the overall performance of such
networks is significantly influenced by the Congestion Control Algorithm (CCA)
which suffers from the problem of bandwidth under-utilization, especially if
the applied buffer regime is very small. In this paper, a novel loss-based CCA
tailored for high-speed and Short-Distance (SD) networks, namely Agile-SD, has
been proposed. The main contribution of the proposed CCA is to implement the
mechanism of agility factor. Further, intensive simulation experiments have
been carried out to evaluate the performance of Agile-SD compared to Compound
and Cubic which are the default CCAs of the most commonly used operating
systems. The results of the simulation experiments show that the proposed CCA
outperforms the compared CCAs in terms of average throughput, loss ratio and
fairness, especially when a small buffer is applied. Moreover, Agile-SD shows
lower sensitivity to the buffer size change and packet error rate variation
which increases its efficiency.Comment: 12 Page
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