Abstract—Recently, many overlay applications have emerged in the Internet, such as peer-to-peer file sharing, end host multicasting, and content distribution network. Currently, each of these applications requires their proprietary functionality support, such as network topology discovery, routing path selection, fault detection and tolerance, etc. A general unified framework may be a desirable alternative to application-specific overlays. In this paper, we introduce the concept of overlay brokers (OBs). We assume that each autonomous system in the Internet has one or more OBs. These OBs cooperate with each other to form an overlay service network (OSN) and provide overlay service support for overlay applications, such as resource allocation and negotiation, overlay routing, topology discovery, and other functionalities. The scope of our effort is the support of quality-of-service (QoS) in overlay networks. In this paper, our primary focus is on the design of QoSaware routing protocols for overlay networks (QRONs). The goal of QRON is to find a QoS-satisfied overlay path, while trying to balance the overlay traffic among the OBs and the overlay links in the OSN. A subset of OBs, connected by the overlay paths, can form an application specific overlay network for an overlay application. The proposed QRON algorithm adopts a hierarchical methodology that enhances its scalability. Two different types of path selection algorithms are analyzed in our paper. We have simulated the protocols based on the transit-stub topologies produced by GT-ITM. Simulation results have shown that the proposed algorithms perform well in providing QoS-aware overlay routing service. Index Terms—Modified shortest distance path (MSDP), overlay brokers (OBs), overlay routing, overlay service network (OSN), proportional bandwidth shortest path (PBSP), quality-of-service (QoS)-aware routing in overlay networks (QRONs), QoS satisfaction ratio. I.

Group communication has become increasingly important in mobile ad hoc networks (MANET). Current multicast routing protocols in MANET have been shown to have large overhead due to dynamic network topology. To overcome this problem, there is a recent shift towards stateless multicast in small groups (DDM [1]). DDM queries the underlying unicast routing protocol to forward data packets towards members of a multicast group. The multicast distribution tree in DDM is implicit and cannot be controlled by the upper transport and application layers.

Multi–constrained Quality of Service (QoS) routing finds a route in the network that satisfies multiple independent quality of service constraints. This problem is NP–hard and a number of heuristic algorithms have been proposed to solve the problem. This paper studies two heuristics, the limited granularity heuristic and the limited path heuristic, for solving general –constrained problems. Analytical and simulation studies are conducted to compare the time/space requirements of the heuristics and the effectiveness of the heuristics in finding the paths that satisfy the QoS constraints. We prove analytically that for an nodes and edges network with (a small constant) independent QoS constraints, the limited granularity heuristic must maintain a table of size in each node to be effective, which results in a time complexity of. We also prove that the limited path heuristic can achieve very high performance by maintaining entries in each node, which indicates that the performance of the limited path heuristic is not sensitive to the number of constraints. We conclude that although both the limited granularity heuristic and the limited path heuristic can efficiently solve –constrained QoS routing problems, the limited path heuristic is superior to the limited granularity heuristic in solving –constrained QoS routing problems "!$ # when. Our simulation study further confirms this conclusion. 1

Many value-added and content delivery services are being offered via service level agreements (SLAs). These services can be interconnected to form a service overlay network (SON) over the Internet. Service composition in SON has emerged as a cost-effective approach to quickly creating new services. Previous research has addressed the reliability, adaptability, and compatibility issues for composed services. However, little has been done to manage generic quality-of-service (QoS) provisioning for composed services, based on the SLA contracts of individual services. In this paper, we present QUEST, a QoS assUred composEable Service infrasTructure, to address the problem. QUEST framework provides: (1) initial service composition, which can compose a qualified service path under multiple QoS constraints (e.g., response time, availability). If multiple qualified service paths exist, QUEST chooses the best one according to the load balancing metric; and (2) dynamic service composition, which can dynamically recompose the service path to quickly recover from service outages and QoS violations. Different from the previous work, QUEST can simultaneously achieve QoS assurances and good load balancing in SON.

Providing quality-of-service (QoS) guarantees in packet networks gives rise to several challenging issues. One of them is how to determine a feasible path that satisfies a set of constraints while maintaining high utilization of network resources. The latter objective implies the need to impose an additional optimality requirement on the feasibility problem. This can be done through a primary cost function (e.g., administrative weight, hop-count) according to which the selected feasible path is optimal. In general, multi-constrained path selection, with or without optimization, is an NP-complete problem that cannot be exactly solved in polynomial time. Heuristics and approximation algorithms with polynomialand pseudo-polynomial-time complexities are often used to deal with this problem. However, existing solutions suffer either from excessive computational complexities that cannot be used for online network operation or from low performance. Moreover, they only deal with special cases of the problem (e.g., two constraints without optimization, one constraint with optimization, etc.). For the feasibility problem under multiple constraints, some researchers have recently proposed a nonlinear cost function whose minimization provides a continuous spectrum of solutions ranging from a generalized linear approximation (GLA) to an asymptotically exact solution. In this paper, we propose an efficient heuristic algorithm for the most general form of the problem. We first formalize the theoretical properties of the above nonlinear cost function. We then introduce our heuristic algorithm (H MCOP), which attempts to minimize both the nonlinear cost function (for the feasibility part) and the primary cost function (for the optimality part). We prove that H MCOP guarantees at least t...

Most of the QoS routing schemes proposed so far require periodic exchange of QoS state information among routers, imposing both communication overhead on the network and processing overhead on core routers. Furthermore, stale QoS state information causes the performance of these QoS routing schemes to degrade drastically. In order to circumvent these problems, we focus on localized QoS routing schemes where the edge routers make routing decisions using only local information and thus reducing the overhead at core routers. We first describe virtual capacity based routing (vcr), a theoretical scheme based on the notion of virtual capacity of a route. We then propose proportional sticky routing, an easily realizable approximation of vcr and analyze its performance. We demonstrate through extensive simulations that adaptive proportional routing is indeed a viable alternative to the global QoS routing approach.

The future Internet is expected to support multicast applications with quality of service (QoS) requirements. To facilitate this, QoS multicast routing protocols are pivotal in enabling new receivers to join a multicast group. However, current routing protocols are either too restrictive in their search for a feasible path between a new receiver and the multicast tree, or burden the network with excessive overhead. We propose QMRP, a new QoS-aware Multicast Routing Protocol. QMRP achieves scalability by significantly reducing the communication overhead of constructing a multicast tree, yet it retains a high chance of success. This is achieved by switching between single-path routing and multiple-path routing according to the current network conditions. The high level design of QMRP makes it operable on top of any unicast routing algorithm in both intra-domain and interdomain. Its responsiveness is improved by using a termination mechanism which detects the failure as well as the succes...

All of the advantages of application-layer overlay networks arise from two fundamental properties: (1) The network nodes in an overlay network, as opposed to lower-layer network elements such as routers and switches, are end systems and have capabilities far beyond basic operations of storing and forwarding; and (2) The overlay topology, residing above a densely connected IP-layer wide-area network, can be constructed and manipulated to suit one's purposes. In this paper, we seek to significantly...

One of the key issues in providing end-to-end quality-of-service (QoS) guarantees in packet networks is how to determine a feasible route that satisfies a set of constraints. In general, finding a path subject to multiple additive constraints (e.g., delay, delay-jitter) is an NP-complete problem that cannot be exactly solved in polynomial time. Accordingly, several heuristics and approximation algorithms have been proposed for this problem. Many of these algorithms suffer from either excessive computational cost or low performance. In this paper, we provide an efficient approximation algorithm for finding a path subject to two additive constraints. The worst-case computational complexity of this algorithm is within a logarithmic number of calls to Dijkstra's shortest path algorithm. Its average complexity is even much lower than that, as demonstrated by simulation experiments. The performance of the proposed algorithm is justified via theoretical bounds that are provided for ...

Bear the provision of Quality of Service (QoS) in the Internet, Differentiated Service (DiffServ) model has been proposed as a cost-effective solution. Traffic is classified into several service classes with different priorities. The premium class traffic has the highest one. The routing algorithm used by the premium class service has significant effects not only on its own traffic, but on all other classes of traffic as well. The shortest hopcount routing scheme used in current Internet turns out to be no longer sufficient in DiffServ networks.