LinklevelMeasurementsfromanbMeshNetwork.pptVIP

Link-level Measurements from an 802.11b Mesh Network Dainel Aguyo, John Bicket,Sanjit Biswas, Glenn Judd, Robert Morris M.I.T , CMU Abstract Roofnet を使用して、実際にMANETを構築 ロスの解析を行なう Roofnet Roofnet Distribution of Delivery Probabilities Links with intermediate loss rates are common, with no sharp transition between high and low packet loss rates. Spatial Distribution of Loss Rate Inter-node distance is not strongly correlated with whether nodes can communicates. Time Variation of Loss Rate Most links have non-bursty loss patterns. Effect of Signal-to-Noise Ratio Links with very high signal strengths are likely to have low loss rates, but in general signal strength has little predictive value. Effect of Transmit Bit-rate A link is likely to have a significant loss rate at its optimum 802.11b bit-rate. Effect of Multi-path Mutil-path fading greatly affects outdoor links and helps explain intermediate loss rates Comparison of Routing Metrics for Static Multi-Hop Wireless Networks Richard Draves, Jitendra Padhy, Brian Zill Microsoft Research Abstract DSR like のMANETプロトコルを実装して、Path Metric の違いによる、性能評価を行なう。 Metric – ETX, Per-hop RTT, per-hop packet pair, minimum-hop Link Quality Metrics Hop Count: shortest-path routing RTT: round-trip time latency PktPair: packet-pair latency ETX: expected transmission count Ad Hoc Routing Architecture DSR + support link quality metric（Link-Quality Source Routing) Supports IPv4, IPv6 etc unmodified Supports multiple link technologies Impact of Long Lived TCP Flows Route Flapping のため、RTT?PktPairは性能が良くない Impact of Path Length EXTは shortest hop より、hop数の多い経路を使用している Impact of Path Length(Cont.) Multiple Simultaneous TCP Transfer pktpair は ホップ数が増えるほど低下 Web-like TCP Transfers Hop 数が長いと、ETXのほうがHOPに比べ性能がよい A Mobile Scenario ETX ではノードの移動による経路品質の変化に対し、適応できない * * Ethernet 802.11 802.16 Mesh Connectivity Layer (with LQSR) IPv4 IPv6 IPX *