Link Layer Topology Discovery And Enabling Wi-Fi Diagnostics For Network Performance Tuning Gabe Frost and Glenn Ward Windows Core Networking Microsoft Corporation.
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Link Layer Topology Discovery And Enabling Wi-Fi Diagnostics For Network Performance Tuning Gabe Frost and Glenn Ward Windows Core Networking Microsoft Corporation What You’ll Learn Top issues impacting user experience and perception of product quality (Wi-Fi) Hardware and Software vendors What to support in WLAN AP to avoid performance degradation What to support in NIC driver to enable diagnostics for Network Performance Tuning The role of LLTD and additional value provided AV-Capable Home Networks Consumers demand simplicity and reliability No-new-wires Focus on WiFi Audio/Video (AV) networks Consumer Electronics (CE) centric, not Information Technology (IT) centric Multiple configuration/upgrades is costly AV networking shouldn’t require an expert Can’t avoid all problem conditions, so… Actionable diagnostics necessary to remove “magic” in network setup Top Issues: No-New-Wires No-new-wires networks are shared resource 2.4 GHz WiFi dominant home network Wireless highly susceptible to performance degradation and non-optimal setup Backward compatibility for legacy devices Interference from nearby networks Microwave, cordless phone, etc. (common RF) Concurrent use of shared network (cross-traffic) Distance and obstructions (walls, floors, people) Setup: Dual-band selection, unsupported topologies 5 GHz solves most (not all) Diagnostics provided for each top issue Diagnostics Business Opportunity Xbox 360 has built-in Media Center Extender About 5 million projected sales by June Significant Xbox WiFi adapter sales Windows XP Media Center Edition is currently top consumer SKU Windows Vista Home Premium and Ultimate Editions provide Media Center (no separate SKU/software) Media Center Extender software licensing and porting kit available for non-Windows Lineup of Media Center Extenders coming Network Performance Tuner Validate and tune network for Media Center Extender (MCX) use (i.e. AV networking) Verify end-to-end throughput Can path support Standard Definition (SD)? High Definition (HD)? Identify and diagnose WiFi performance degradation on first use and during run-time Ensure proper network setup before AV use Inform what caused run-time quality issue Requires NDIS6 NWF driver on Windows Vista NPT Integral To Media Center 2.4 GHz Legacy Compatibility 802.11g theoretical 54 Mbps not possible 1/3 feasible in perfect conditions Legacy 802.11b devices further impact perf Any associated legacy device reduces bandwidth by ½ or more (not sending data) Even if not on end-to-end media path Associated Disassociated Nearby 802.11 Interference Performance impacted by co-channel and adjacent-channel interference E.g. 4 Mbps on co-channel will reduce throughput by ~4 Mbps Impacts Close-proximity dwellings Default static channel out-of-box exacerbates problem NPT diagnoses and identifies clearest channel General RF Interference Common household interference greatly impacts 2.4 GHz WiFi Microwave Oven Cordless Phone Connection Loss 5 GHz (dual-band) AP solves this problem NPT will identify if causing congestion during run-time Concurrent Network Use Commonly referred to as cross-traffic WiFi (2.4 and 5 GHz) is a shared medium, so concurrent use reduces available bandwidth Impacts all shared mediums, not just WiFi Examples (contend with ongoing AV streams) Heavy Internet use File transfers Network print or backup Dual-band AP mitigates this problem AV on 5 GHz and data-oriented on 2.4 GHz NPT will identify if causing congestion during run-time Source of cross-traffic must implement Link Layer Topology Discovery (LLTD) Detecting Cross-Traffic As Cause Of Congestion (Using LLTD) Distance And Obstructions Performance degraded if MCX and AP are separated by walls and floors Also moving obstructions (people) Impacts both 2.4 GHz and 5 GHz NPT will diagnose if causing congestion during run-time Common Setup Problems Dual-band AP (5 GHz and 2.4 GHz) available, but connected to 2.4 GHz NPT detects this situation Both Media Center and MCX on same radio Commonly referred to as double-hop Effectively ½ available bandwidth (or worse) Media Center wired, MCX Wireless Double-Hop (both connected to same WiFi radio) Link Layer Topology Discovery (LLTD) Glenn Ward Microsoft Corporation Windows® Rally™ Program Access to Technologies Simple Unified License Technical Guidance Windows® Rally™ Devices Effortless to configure and maintain Reliable and simple to manage More secure and provide rich digital experiences Windows Rally Experiences Technologies Management Interfaces Function Discovery Discovery Connect SetupNow Windows Wireless MapMap Topology LLTD: Network Service QoSofExtensions LLTD: Quality Applications Plug Device andSpecific Play Extensions Drivers AV UPnP Devices IP Network (IPv4, IPv6) Ethernet/Wireless Experiences Windows Rally Technologies Device Networked Profile for Web Devices Services Problem Statement Users have difficulties troubleshooting issues on their network Partners have few support tools for their device and/or service Home Networks growing in sophistication Was: Internet Sharing for email, Web surfing Now and future: Streaming from WAN, cross-home Media Delivery Latency-sensitive Broadband Services: IPTV, VoIP, Gaming Unrealized scenarios -> product returns, smaller TAM Home Networking complexity calls for better infrastructure tools Solved Via Windows Vista Network Map/LLTD LLTD – Link Layer Topology Discovery Discovery, Topology and Diagnostics, below Internet Layer No Dependency on NID intelligence to function Detect Legacy Hub, Switch, AP, Half-Bridge Ensures correct problem isolation Ensures network robustness – bandwidth, cross-traffic detection Windows Vista UI Sample Map Business Value Raise visibility, perceived value of networks and IP devices! No longer plumbing component Device Capabilities Delivery Identified in UI Give credit (good/bad) where due Leverage LLTD as L2 Bootstrapping protocol Provide you with opportunity to showcase your Industrial Design Brand Device Capabilities Porting Kit ‘Beta 1’ Contents Source Code Reference LLTD implementations Test Suite User’s Guide and FAQ Protocol Spec Mandatory/Optional call-outs .ICO creation guidelines QoS Extensions To LLTD Provides packet time-stamping for bandwidth and diagnostic experiments Mandatory if your device handles QoS-sensitive traffic (Audio/Video) Mandatory component for all Media Center Extender (MCX) devices E.g. Xbox 360 Media Center must see sufficient bandwidth Stream won’t receive priority if poor results returned Feature Overview Closing Info XP Responder: OOB Release License No cost, simple licensing terms Licensees receive LLTD Porting Kit Questions LLTDinfo @ microsoft.com Call To Action IHV: Meet Designed for Windows Gold requirements Build dual-band WLAN AP IHV: Download LLTD reference implementation and incorporate into router/AP and media player devices QoS extensions critical ISV: Implement NDIS6 Native WiFi (NWF) drivers All OIDs required by diagnostics are mandatory in NWF Additionally Set lRSSI field of DOT_11_RECV_CONTEXT per-packet NDIS_MINIPORT_ADAPTER_NATIVE_802_11_ATTRIBUTES Set at initialization time Additional Resources Web Resources Blog http://blogs.msdn.com/wndp Windows Rally Technologies Residential gateway implementation guide http://www.microsoft.com/whdc/device/network/ homenet/WAP_reqs.mspx © 2006 Microsoft Corporation. All rights reserved. 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