We have developed an automatic network configuration technology for flexible and robust network construction. In this paper, we propose a two-or-more-level hierarchical link-state routing protocol in Hierarchical QoS ...
详细信息
We have developed an automatic network configuration technology for flexible and robust network construction. In this paper, we propose a two-or-more-level hierarchical link-state routing protocol in Hierarchical QoS link Information protocol ( HQLIP). The hierarchical routing easily scales up the network by combining and stacking configured networks. HQLIP is designed not to recompute shortest-path trees from topology information in order to achieve a high-speed convergence of forwarding information base ( FIB), especially when renumbering occurs in the network. In addition, we propose a fixed-midfix renumbering ( FMR) method. FMR enables an even faster convergence when HQLIP is synchronized with Hierarchical/ Automatic Number Allocation ( HANA). Experiments demonstrate that HQLIP incorporating FMR achieves the convergence time within one second in the network where 22 switches and 800 server terminals are placed, and is superior to Open Shortest Path First ( OSPF) in terms of a convergence time. This shows that a combination of HQLIP and HANA performs stable renumbering in link-state routing protocol networks.
The efficiency with which the routingprotocol of a multihop packet-radio network uses transmission bandwidth is critical to the ability of the network nodes to conserve energy. We present and verify the source-tree a...
详细信息
The efficiency with which the routingprotocol of a multihop packet-radio network uses transmission bandwidth is critical to the ability of the network nodes to conserve energy. We present and verify the source-tree adaptive routing (STAR) protocol, which we show through simulation experiments to be far more efficient than both table-driven and on-demand routingprotocols proposed for wireless networks in the recent past. A router in STAR communicates to its neighbors the parameters of its source routing tree, which consists of each link that the router needs to reach every destination. To conserve transmission bandwidth and energy, a router transmits changes to its source routing tree only when the router detects new destinations, the possibility of looping, or the possibility of node failures or network partitions. Simulation results show that STAR is an order of magnitude more efficient than any topology-broadcast protocol proposed to date and depending on the scenario is up to six times more efficient than the Dynamic Source routing (DSR) protocol, which has been shown to be one of the best performing, on-demand routingprotocols.
Legacy IP routing restricts the efficacy of traffic engineering solutions. This restriction stems from the constraint that traffic at a node must be uniformly split across all next-hop nodes corresponding to equal cos...
详细信息
Legacy IP routing restricts the efficacy of traffic engineering solutions. This restriction stems from the constraint that traffic at a node must be uniformly split across all next-hop nodes corresponding to equal cost shortest path to a destination. Proposals that alleviate this constraint either completely overhaul legacy IP routing, or introduce complex control and/or forwarding plane components. This additional complexity departs from the elegant simplicity of legacy routingprotocols where statically optimized link weights embed all traffic engineering semantics. We present Interface Split routing (ISR), which retains the basic forwarding and control mechanism of legacy IP routing. Furthermore, a set of link weights embed all traffic engineering semantics in ISR. However, ISR makes possible finer-grained traffic engineering by configuring independent sets of next-hops to a destination at each incoming interface. This]ends itself well to modern router architectures where each incoming interface has its own forwarding table. Consequently, at the aggregated node level, traffic to a particular destination may be non-uniformly distributed across next-hop nodes. Hence, ISR allows additional flexibility in routing traffic as compared to default IP routing while retaining its simplicity. We conduct simulation studies on representative ISP topologies to compare ISR with traditional link-weight-optimized routing. ISR reduces the difference between optimal routing and-weight-optimized routing by 50%. (c) 2007 Elsevier B.V. All rights reserved.
Low earth orbit (LEO) satellite networks equipped with inter-satellite links (ISLs) will be an indispensable component of the future Internet. routingprotocol installed on LEO satellite networks plays a significant r...
详细信息
ISBN:
(纸本)9798350305883;9798350305890
Low earth orbit (LEO) satellite networks equipped with inter-satellite links (ISLs) will be an indispensable component of the future Internet. routingprotocol installed on LEO satellite networks plays a significant role on achieving efficient data delivery. LEO satellite networks exhibit two typical topology features, i.e., deterministic neighbor relationship and intermittent ISLs, which are different from terrestrial Internet. Hence the classic link-state routing protocols (e.g., OSPF) designed for terrestrial Internet are naturally unable to accommodate these topology features. In this paper, we present the design of localized fine-grained (LoFi) link-state routing protocol for LEO satellite networks. The key idea of LoFi is to reduce the dissemination range of coarse-grained link connectivity and incorporate finegrained link-load awareness. Specifically, LoFi has two key parameters, i.e., state dissemination range and load variation threshold, which determine how far to disseminate linkstate update and how precise to detect the link load change, respectively. The two parameters allow the LEO satellite networks to flexibly achieve a desired tradeoff between good packet delivery performance and small control overhead. We evaluate the performance of LoFi via extensive packet-level experiments on OMNeT++ under Iridium constellation. Results show that LoFi improves the packet delivery performance (up to 94.4%) and reduces the control overhead (up to 85.7%) compared to state-of-the-art link-stateprotocol ELB.
OMNeT++ je diskrétní modulární simulátor, často využívaný pro simulaci počítačových sítí. Univerzální simulátor lze doplnit různými rozšiřuj&#...
详细信息
OMNeT++ je diskrétní modulární simulátor, často využívaný pro simulaci počítačových sítí. Univerzální simulátor lze doplnit různými rozšiřujícími balíky např. INET Framework, který slouží pro simulaci zařízení a protokolů síťového zásobníku TCP/IP. V této práci, zkoumáme možnosti balíku INET v oblasti směrování, tedy dynamické směrovací protokoly. Konkrétně se práce zaměřuje na protokol OSPF pro IPv6 sítě (OSPFv3). Protokol je v této práci představen a jsou zde vysvětleny principy jeho fungování. V práci je navrhnut modul OSPFv3 pro simulování protokolu a je z části implementován.
Because most link-state routing protocols, such as OSPF and IS-IS, calculate routes using the Dijkstra algorithm, which poses scalability problems, implementors often introduce an artificial delay to reduce the number...
详细信息
Because most link-state routing protocols, such as OSPF and IS-IS, calculate routes using the Dijkstra algorithm, which poses scalability problems, implementors often introduce an artificial delay to reduce the number of route calculations. Although this delay directly affects IP packet forwarding, it can be acceptable when the network topology does not change often. However, when the topology of a network changes frequently, this delay can lead to a complete loss of IP reachability for the affected network prefixes during the unstable period. In this paper, we propose the Cached Shortest-path Tree (CST) approach, which speeds up intra-domain routing convergence without extra execution of the Dijkstra algorithm, even if the routing for a network is quite unstable. The basic idea of CST is to cache shortest-path trees (SPTs) of network topologies that appear frequently, and use these SPTs to instantly generate a routing table when the topology after a change matches one in the caches. CST depends on a characteristic that we found from an investigation of routing instability conducted on the WIDE Internet in Japan. That is, under unstable routing conditions, both frequently changing linkstate Advertisements (LSAs) and their instances tend to be limited. At the end of this paper, we show CST's effectiveness by a trace-driven simulation.
暂无评论