[信息与通信]国外无线网络设计方案.ppt

CAMPUS NETWORK DESIGN: Wired vs. Wireless,Terry Gray Director, Networks & Distributed Computing UW Computing & Communications September 2001,Scope of UW Networking,UW Campus Networks Seattle Tacoma Bothell/CCC Medical Centers (net design) UW Physicians Network UW Medical Center Harborview Medical Center Pacific/NorthWest Gigapop Pacific Wave exchange point Pacific Light Rail Statewide K20 Network,Pacific Northwest Gigapop,Baseline Connectivity,Shared 10Mbps HD Switched 10Mbps HD Switched 10/100Mbps FD backed by GE switch/router infrastructure Goal: Switched 10/100 FD for all; GE for a few Reality: Cat3 wireplant upgrade will take multiple years and multiple millions of dollars,Advanced Services,Multicast Partially deployed Older routers need to be replaced QoS Laissez faire? Premium service? Best with FD connections. VoIP Needs QoS, extra-high availability POE desirable; implies UPS in closets IPv6,Premium Services?,Wide-area QoS chargeback? Preferred access to Internet for a fee? Lots of interesting policy and tech issues.,Mistakes We Didnt Make,FDDI to the desk VLANs ATM Various “cut-thru IP switching“ digressions Claim: Staying with pure IP and Ethernet has served UW very well.,Current Statistics,Avg Backbone traffic: nearly 2 TB/day Peak Inbound traffic: 100 Mbps (40 in 1999) Peak Outbound traffic: 160 Mbps (20 in 1999) Doubling time: Less than 2 years! Hosts: over 50,000 Modems: over 2,000 Switched subnets: 70% (30% in 1999) 10/100 FD subnets: 25% (5% in 1999) Cat 5 buildings: 10%,UW-S Building/Subnet Status,GigE Buildings,Physics/Astronomy Fisheries Center new Ocean Lander Hall McCarty Hall Parrington Hall Edmondson Pavillion Mary Gates Hall OUG Library,part of Electrical Engr. part of HS K wing part of HS T wing part of Johnson Hall part of Savery part of Thomson Hall part of 4545,Simplified Network Topology,Router,Router,Border Router,Core Switch,Edge Switch,Edge Switch,Interior Switch,Interior Switch,Gigapop,Internet2,Desktop,Desktop,Internet,Fed Nets,4,30,300,1000+,Branch Site,50,000,PBX,Number of Devices,Backbone Traffic,Border Traffic 1999,Border Traffic 2001,Recurring Theme: Explosive Growth,More users More devices Longer use New (bandwidth-intensive) applications e.g. remote collaboration tools audio/video streaming tele-immersion distance learning,Networking Hot List,Campus building/subnet upgrades Backbone upgrades (production, experimental) Regional networking Network Hardening Security Advanced Services Wireless Management/diagnostic tools,Success Metrics,10/100 FD connections: xx% Multicast deployment: xx% QoS deployment: xx% Deptl wireless coverage: xx% Router center hardening: xx% Backbone capacity IPv6 capable routers,On to Wireless.,Wireless Categories,Wireless by Purpose Point-to-Point links Access networks Wireless by Spectrum Infrared RF Optical,Wireless RF by Range,PAN/HAN (Personal/Home-Area-Network) Bluetooth HomeRF LAN (Local-Area-Network) IEEE 802.11 ETSI HiperLAN2 MAN (Metro-Area-Network) LMDS, “Fixed Wireless” WAN (Wide-Area-Network) Ricochet (R.I.P.) CDPD 2.5G, 3G, etc, etc, etc,LAN Wireless Standards,IEEE 802.11 2.4GHz, 1-2Mbps, FHSS, DSSS IEEE 802.11b 2.4Ghz, 11Mbps DSSS (WiFi) IEEE 802.11a 5Ghz, 54Mbps ETSI HiperLAN2 5Ghz, 54Mbps, TDMA In US, all use unlicensed “ISM” bands,802.11 ISSUES,Network Design, esp. Topology Access control Security Compatibility Interference Relation to Bluetooth, HomeRF, etc Obsolescence,ROAMING ISSUES,Layer 2 (802.11) vs. Layer 3 (Mobile IP) Vendor incompatibility LAN vs. WAN We will support L2 roaming within a building by dedicating one subnet for all access points in the building.,Policy Issues,Part of campus network infrastructure Want to encourage small-scale deployments with minimum overhead, but coordination needed to avoid interference Large-scale deployments need to be coordinated by C&C Campus-wide access control policy,UW-S Wireless Deployment,C&C Pilot Project Kane Hall, Rm. 130 Mary Gates Hall Gerberding Hall Odegaard Undergraduate Library Other wireless projects CS, C&C, Business, MCIS, .,Pilot Project Objectives,Provide 11 Mb coverage throughout selected facilities. Allow roaming within facility space. Develop suitable policies. Gain operational experience.,Pilot Project Lessons Learned,Success depends on cooperation w/depts It takes more wire than you think! Site surveys use SSH, SSL, etc. Technology still evolving 2.4GHz phones interfere badly,Wired vs. Wireless Issues,Server suitability Performance Performance variation Price/Performance Interference Technology maturity Advanced services Security,802.11a: Successor?,Faster Shorter distance More power consumption Probably wont replace 802.11b Probably need WAPs for both,Infrastructure Requirements,Conclusions,Wireless is very addictive. It will be very popular. It will be very problematic. The dust has not settled. In offices, it is not a replacement for wired. In classrooms, lounges, etc, it is but that still requires some wired infrastructure.,Wireless References,Open Group: Wireless Ethernet Compatibility Alliance (WECA) Wireless LAN Association (WLA