Congestion Minimization for Multipath Routing via Multiroute Flows

Congestion minimization is a well-known routing problem for which there is an O(log n/loglog n)-approximation via randomized rounding due to Raghavan and Thompson. Srinivasan formally introduced the low-congestion multi-path routing problem as a generalization of the (single-path) congestion minimization problem. The goal is to route multiple disjoint paths for each pair, for the sake of fault tolerance. Srinivasan developed a dependent randomized scheme for a special case of the multi-path problem when the input consists of a given set of disjoint paths for each pair and the goal is to select a given subset of them. Subsequently Doerr gave a different dependentrounding scheme and derandomization. Doerr et al. considered the problem where the paths have to be chosen, and applied the dependent rounding technique and evaluated it experimentally. However, their algorithm does not maintain the required disjointness property without which the problem easily reduces to the standard congestion minimization problem. In this note we show a simple algorithm that solves the problem correctly without the need for dependent rounding --- standard independent rounding suffices. This is made possible via the notion of multiroute flows originally suggested by Kishimoto et al. One advantage of the simpler rounding is an improved bound on the congestion when the path lengths are short

Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work

Decisive analysis of current state of the art in congestion aware and control routing models in ad hoc networks

An important aspect that portrays a crucial position in the ad hoc network routing is congestion. Almost every research analysis is en-route in adapting this key factor in addressing congestion. This problem cannot be totally addressed by the regular TCP protocol based networks, keeping in view the special assets which include multi hop sharing etc, which is difficult to ascertain in ad hoc networks. Many attempts have been made and are in progress by researchers to provide unique solutions to the above mentioned problems. This paper projects a vital study on jamming aware and different routing standards that have been dealt with in recent times

A Competitive Algorithm for Random-Order Stochastic Virtual Circuit Routing

We consider the virtual circuit routing problem in the stochastic model with uniformly random arrival requests. In the problem, a graph is given and requests arrive in a uniform random order. Each request is specified by its connectivity demand and the load of a request on an edge is a random variable with known distribution. The objective is to satisfy the connectivity request demands while maintaining the expected congestion (the maximum edge load) of the underlying network as small as possible. Despite a large literature on congestion minimization in the deterministic model, not much is known in the stochastic model even in the offline setting. In this paper, we present an O(log n/log log n)-competitive algorithm when optimal routing is sufficiently congested. This ratio matches to the lower bound Omega(log n/ log log n) (assuming some reasonable complexity assumption) in the offline setting. Additionally, we show that, restricting on the offline setting with deterministic loads, our algorithm yields the tight approximation ratio of Theta(log n/log log n). The algorithm is essentially greedy (without solving LP/rounding) and the simplicity makes it practically appealing