Cross‐layer and cognitive QoS management system for next‐generation networking

SUMMARYHot-potato routing is a border gateway protocol policy that selects the 'closest' egress router in terms of interior gateway protocol cost. This policy imposes inherent interactions between intra-AS (Autonomous System) and inter-AS traffic engineering. In light of this observation, we present a hybrid intra-AS and inter-AS traffic engineering scheme named egress selection based upon hot potato routing. This scheme involves link weight optimization, which can not only minimize the time that IP (Internet Protocol) packets travel across the network by assigning specified egress router but also balance the load among the internal links of the transit network. Egress selection based upon hot potato routing also incorporates multi-topology routing technique to address the problem that one set of link weights might not guarantee specified egress routers. Accordingly, we formulate the link weights optimization problem using multi-topology routing as a mixed integer linear programming model. And we present a new heuristic algorithm to make the problem tractable. Numerical results show that only a few topologies are needed to guarantee specified egress router, and maximum link utilization is also reduced.

Section: Egress Selection Based Upon Hot-potato Routingmentioning

confidence: 99%

Multi‐topology routing based egress selection approach to achieve hybrid intra‐AS and inter‐AS traffic engineering

Wang

et al. 2014

“…Reviews of cross-layer designs and proposed metrics are presented in [13][14][15]. Therefore, to be more efficient, routing protocols for wireless networks should be aware of such lower-layer problems.…”

Section: Wireless Mesh Network Routing Protocolsmentioning

confidence: 99%

Efficient routing for wireless mesh networks using a backup path

Esmailpour

Dallal

2012

Wireless mesh networks (WMNs) have a proven record in providing viable solutions for some of the fundamental issues in wireless networks such as capacity and range limitations. WMN infrastructure includes clusters of mobile ad-hoc networks connected through a fixed backbone of mesh routers. The mesh network can be constrained severely because of various reasons, which could result in performance degradation such as a drop in throughput or long delays. Solutions to this problem often focus on multipath or multichannel extensions to the existing ad-hoc routing protocols. In this paper, we propose a novel solution by introducing an alternative path to the mesh backbone that traverses the mobile ad-hoc networks part of the WMN. The new routing solution allows the mobile nodes (MNs) to establish direct communication among peers without going through the backbone. The proposed alternative ad-hoc path is used only when the mesh backbone is severely constrained. We also propose, for the first time in WMNs, using MNs with two interfaces, one used in the mesh backbone communication and the other engaged in the ad-hoc network. A scheme is presented for making the MN aware of link quality measures by providing throughput values to the ad-hoc on-demand distance vector protocol. We use piggybacking on route reply messages in ad-hoc on-demand distance vector to avoid incurring additional costs. We implemented our solution in an OPNET simulator and evaluated its performance under a variety of conditions. Simulation results show that the alternative ad-hoc path provides higher throughput and lower delays. Delay analysis show that the throughput improvement does not impose additional costs.WMN has a major component on the access network with clusters of mobile ad-hoc nodes. In this research study, we focus on the access network rather than the backbone. We propose an efficient routing system for WMN that utilizes both backbone and access links, while introducing a backup path to be used when the backbone is constrained. The WMN backbone is formed by fixed wireless routers; thus, its topology does not change frequently. This allows us to employ link-state routing in the backbone. MNs connected to the WMRs in the backbone could also make direct connection with their peers through their access links to form the mobile ad-hoc network (MANET). MANET topology undergoes frequent changes because of the mobility of MNs. Therefore, an on-demand routing protocol such as ad-hoc on-demand distance vector (AODV) is more suitable for this part of the network. Our proposed routing system provides a solution for routing of WMNs with at least two alternative paths: one through the MANET called the ad-hoc path (ah_path), and the other through the backbone, called the backbone path (bb_path). WMRs in the backbone are fixed; therefore, the bb_path is more stable than the ah_path and has no power constraints. In contrast, the ah_path is relatively unstable with power constraints because of the mobility and limited power source of user devices. Hence, t...

“…In [21], an adaptive cross-layer and cognition concept is used to select the optimal access network for services based on the QoS specifications of 3G, WiMAX, and WiFi wireless access technologies. On the other hand, the cross layer scheme is used to increase the level of cooperation and communication between layers without changing the basic functions of each [22].…”

Section: Cross Layer Approachmentioning

confidence: 99%

QoS aware transmission control scheme for multihop WiMAX network

Ismael

Yusof

Abbas

et al. 2012

The IEEE 802.16j Mobile Multihop Relay (MMR) WiMAX network allows the number of hops between the end user and the base station to be more than two hops. It supports non-real-time Polling Service, which considers the minimum reserved rate and the maximum sustained rate as a QoS requirements. The reliability of sending the data over MMR WiMAX is achieved by using Transmission Control Protocol (TCP) in transport layer and automatic repeat request in the link layer. However, the use of automatic repeat request in the link layer makes the round trip time fluctuate rapidly, which increases the possibility of retransmission timeout (RTO) expiration. TCP performance degrades because of frequent timeout, and hence the QoS transmission rates cannot be satisfied. Therefore, this paper presents an RTO smoothing scheme and QoS aware transmission control to enhance the performance of data transmission over MMR WiMAX networks. The RTO smoothing scheme aims to reduce the frequent timeout occurrences. The slow start threshold and maximum congestion window are adjusted to satisfy the required QoS and it provides transmission rate fairness for the users at different hops. The results showed that, the proposed schemes reduce the timeout, and improve the utilization of the allocated resources and TCP throughput.