University of Washington Computing & Communications
CAMPUS NETWORK DESIGN:Wired vs. Wireless
Terry GrayDirector,
Networks & Distributed ComputingUW Computing & Communications
September 2001
University of Washington Computing & Communications
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
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Pacific Northwest Gigapop
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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
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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
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Premium Services?
• Wide-area QoS chargeback?
• Preferred access to Internet for a fee?
• Lots of interesting policy and tech issues...
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Mistakes We Didn't 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...
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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%
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UW-S Building/Subnet Status
Depts Dorms Hospitals TOTAL
Buildings 193 Cat 3 175 Cat 5 18
Subnets 269- 41 - 310
10Mbps 85 100Mbps 1311000Mbps 94
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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
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Simplified Network Topology
Router Router
BorderRouter
CoreSwitch
EdgeSwitch
Edge Switch
InteriorSwitch
InteriorSwitch
Gigapop Internet2
DesktopDesktop
Internet
Fed Nets4
30
300
1000+Branch Site
50,000
PBX
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Number of Devices
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Backbone Traffic
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Border Traffic 1999
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Border Traffic 2001
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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
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Networking Hot List• Campus building/subnet upgrades• Backbone upgrades (production, experimental)• Regional networking• Network Hardening• Security• Advanced Services• Wireless• Management/diagnostic tools
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Success Metrics
• 10/100 FD connections: xx%
• Multicast deployment: xx%
• QoS deployment: xx%
• Dept’l wireless coverage: xx%
• Router center hardening: xx%
• Backbone capacity
• IPv6 capable routers
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On to Wireless...
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Wireless Categories
• Wireless by Purpose– Point-to-Point links– Access networks
• Wireless by Spectrum– Infrared– RF– Optical
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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
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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
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802.11 ISSUES
• Network Design, esp. Topology
• Access control
• Security
• Compatibility
• Interference
• Relation to Bluetooth, HomeRF, etc
• Obsolescence
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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.
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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
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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, ...
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Pilot Project Objectives
• Provide 11 Mb coverage throughout selected facilities.
• Allow roaming within facility space.
• Develop suitable policies.
• Gain operational experience.
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Pilot Project Lessons Learned
• Success depends on cooperation w/dep’ts
• It takes more wire than you think!
• Site surveys & frequency sweeps needed.
• WEP is not secure; use SSH, SSL, etc.
• Technology still evolving
• 2.4GHz phones interfere badly
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Wired vs. Wireless Issues
• Server suitability• Performance• Performance variation• Price/Performance• Interference• Technology maturity• Advanced services• Security
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802.11a: Successor?
• Faster• Shorter distance• More power consumption• Probably won’t replace 802.11b• Probably need WAPs for both
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Infrastructure Requirements
Phones Wired Wireless
Closets YES YES YES
Conduit YES YES YES
Wireplant YES YES Much
Switches Maybe YES Some
WAPs NO NO YES
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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.
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Wireless References• Open Group: www.openwirelessdata.org• Wireless Ethernet Compatibility Alliance (WECA)• Wireless LAN Association (WLANA)• Portable Computer & Communications Association (PCCA)• Internet Engineering Task Force (IETF)• WAP Forum• Bluetooth Special Interest Group• Mobile Wireless Internet Forum (MWIF)• Wireless Information Networks Forum (WINForum)• HiperLAN2 Global Forum• Wireless Data Forum