| 1. |
- Margasinski, Igor, et al.
(author)
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Low-latency parallel transport in anonymous peer-to-peer overlays
- 2008
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In: IP operations and management / Lecture notes in computer science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540873563 ; 5275, s. 127-141
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Conference paper (peer-reviewed)abstract
- The paper presents a design and discusses configuration aspects of an overlay transport protocol based on an idea of the peer-to-peer direct and anonymous distribution overlay (P2PRIV). We estimate a secure configuration of the protocol and examine a correlation between the P2PRIV’s anonymous path lengths and latency. An increase of the path lengths speaks strongly in favor of the parallel solution’s anonymity, as in classical cascade networks. In the paper we evaluate the new protocol in a scope of a trade-off between anonymity and traffic performance and show that the presented solution allows effectively increasing anonymity with relatively low impact on anonymous transport latency.
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| 2. |
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| 3. |
- Dzida, Mateusz, et al.
(author)
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Design of mixed MPLS/OSPF routing in IP networks
- 2006
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In: Systems Science. - 0137-1223. ; 32:3, s. 55-59
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Journal article (peer-reviewed)abstract
- In this paper, we address some Internet core network optimization issues related to a combination of Open Shortest Path First (OSPF) and Multi Protocol Label Switching (MPLS) routing protocols. Since MPLS can be combined with any routing protocol there has appeared an idea of coupling IP streams routed via the OSPF protocol and MPLS Label Switched Paths (LSPs) in the same network. One expected advantage behind such a combined routing is to adjust the design stage by allowing some flows to be routed via OSPF while others to be transmitted via MPLS LSPs. In the paper we discuss two routing optimization problems. In the first case, OSPF routing protocol works over logical network with generalized IP links. These links are either standard IP links or IP links established as MPLS LSPs. In the second case, we distinguish two types of demands depending on whether OSPF routing is used or packets are switched by MPLS Label Switch Routers (LSR). We present both problem formulations and discuss the question on how to effectively solve these problems.
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| 4. |
- Dzida, Mateusz, et al.
(author)
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Optimization of resilient IP networks with shortest path routing
- 2007
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In: [Host publication title missing]. - 9781424438242
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Conference paper (peer-reviewed)abstract
- In the paper we address traffic engineering problems related to optimization of routing in IP networks applying destination-based shortest path routing (SPR) of the OSPF type. An SPR routing pattern is determined by a system of (administrative) weights defined over the set of IP links: the routes for IP forwarding are determined as the shortest paths computed locally at the nodes using the current link weights. When the shortest path from a certain node (node v, say) to a particular destination (destination t, say) is not unique, the traffic routed from node v to destination t is split equally among all links outgoing from v that belong to the shortest paths to destination t, i.e., according to the Equal Cost Multiple-Paths (ECMP) rule. The basic problem considered in this paper consists in finding a resilient link weight system generating a routing scheme that satisfies given traffic demands and does not lead to link overloads both in the normal network state of operation and in all considered failure states when certain IP links are failed. We assume that if a failure occurs then the weight system is modified by assigning infinite weights to the failed links, and not altering the weights of the remaining, operating links. We consider the traffic engineering goal related to minimization, over all failure states, of the maximal link overload. We formulate the considered problem as a mixed integer programme (MIP) and propose a heuristic algorithm based on the tabu search meta-heuristic. The efficiency of the proposed weight optimization method is illustrated by means of a numerical study.
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| 5. |
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| 6. |
- Pioro, Michal, et al.
(author)
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Application of the max-min fairness principle in telecommunication network design
- 2005
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In: Next Generation Internet Networks, 2005. - 078038900X ; , s. 219-225
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Conference paper (peer-reviewed)abstract
- The rapid growth of traffic induced by Internet services makes the simple over-provisioning of resources not economical and hence imposes new requirements on the dimensioning methods. Therefore, the problem of network design with the objective of minimizing the cost and at the same time solving the tradeoff between maximizing the service data flows and providing fair treatment of all demands becomes more and more important. In this context, the so-called max-min fair (MMF) principle is widely considered to help finding reasonable bandwidth allocation schemes for competing demands. Roughly speaking, MMF assumes that the worst service performance is maximized, and then is the second worst performance, the third one, and so on, leading to a lexicographically maximized vector of sorted demand bandwidth allocations. It turns out that the MMF optimal solution cannot be approached in a standard way (i.e., as a mathematical programming problem) due to the necessity of lexicographic maximization of ordered quantities (bandwidth allocated to demands). Still, for convex models, it is possible to formulate effective sequential procedures for such lexicographic optimization. The purpose of the presented paper is three-fold. First, it discusses resolution algorithms for a generic MMF problem related to telecommunications network design. Second, it gives a survey of network design instances of the generic formulation, and illustrates the efficiency of the general algorithms in these particular cases. Finally, the paper discusses extensions of the formulated problems into more practical (unfortunately non-convex) cases, where the general for convex MMF problems approach fails.
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| 7. |
- Pioro, Michal, et al.
(author)
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Path generation issues for survivable network design
- 2008
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In: Computational Science and Its Applications /Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783540698401 ; 5073, s. 820-835
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Conference paper (peer-reviewed)abstract
- Link dimensioning and routing problems in resilient network design are considered. Reliable network operation is ensured by means of flow restoration which is performed on preselected protection (backup) paths that can absorb traffic overflows from failed primary paths. Backup and primary flows use separated link capacities, and can be split among many paths. In the paper, two restoration models are considered. The first model assumes that once the backup path is assigned it must be used in every state in which the protected primary path fails while the second model allows different protection paths to be used in different network failure states. The problems are formulated as multiple commodity linear programming (LP) models using the link-path (L-P) notation and solved by the column generation technique. Consequent pricing models and algorithms are introduced. Computational efficiency of the presented approaches is analyzed. The research was partially supported by the Dean’s grant from the Faculty of Electronics and Information Technology, Warsaw University of Technology.
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| 9. |
- Tomaszewski, Artur, et al.
(author)
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Valid inequalities for a shortest-path routing optimization problem
- 2007
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Conference paper (peer-reviewed)abstract
- In autonomous systems of the Internet packets are routed on shortest paths to their destinations, for example according to the ECMP principle. The problem of finding a feasible traffic routing configuration realized on paths which can be generated by a system of weights assigned to IP links is NP-hard. This problem can be formulated as a mixed-integer program and attempted with a branch-and-cut algorithm if effective cuts (valid inequalities) can be derived. In this paper we present exact and approximate LP- and MIPbased methods for generating valid inequalities that separate fractional solutions of the basic problem. Besides, a family of complementary valid inequalities, generated with a shortest-path algorithm, related to combinatorial properties of feasible traffic routes is introduced to speed up the cut generation process. Results of a numerical study illustrating computational issues are discussed.
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