University of Washington
Computing & Communications
CAMPUS NETWORK DESIGN:
Wired vs. Wireless
Terry Gray
Director,
Networks & Distributed Computing
UW 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
University of Washington
Computing & Communications
Pacific Northwest Gigapop
University of Washington
Computing & Communications
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
University of Washington
Computing & Communications
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
University of Washington
Computing & Communications
Premium Services?
• Wide-area QoS chargeback?
• Preferred access to Internet for a fee?
• Lots of interesting policy and tech issues...
University of Washington
Computing & Communications
Mistakes We Didn't Make
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FDDI to the desk
VLANs
ATM
Various "cut-thru IP switching" digressions
• Claim: Staying with pure IP and Ethernet
has served UW very well...
University of Washington
Computing & Communications
Current Statistics
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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%
University of Washington
Computing & Communications
UW-S Building/Subnet Status
Depts Dorms Hospitals TOTAL
193
175
18
Buildings
Cat 3
Cat 5
Subnets
10Mbps
100Mbps
1000Mbps
269-
41
-
310
85
131
94
University of Washington
Computing & Communications
GigE Buildings
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Physics/Astronomy
Fisheries Center
new Ocean
Lander Hall
McCarty Hall
Parrington Hall
Edmondson Pavillion
Mary Gates Hall
OUG Library
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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
University of Washington
Computing & Communications
Simplified Network Topology
Core
Switch
4
Fed Nets
30
Router
Router
300
Interior
Switch
Interior
Switch
Border
Router
Gigapop
Internet2
Internet
PBX
1000+
Edge
Switch
Edge
Switch
50,000
Desktop
Desktop
Branch
Site
University of Washington
Computing & Communications
University of Washington
Computing & Communications
Number of Devices
University of Washington
Computing & Communications
Backbone Traffic
University of Washington
Computing & Communications
Border Traffic 1999
University of Washington
Computing & Communications
Border Traffic 2001
University of Washington
Computing & Communications
Recurring Theme: Explosive Growth
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More users
More devices
Longer use
New (bandwidth-intensive) applications
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e.g. remote collaboration tools
audio/video streaming
tele-immersion
distance learning
University of Washington
Computing & Communications
Networking Hot List
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Campus building/subnet upgrades
Backbone upgrades (production, experimental)
Regional networking
Network Hardening
Security
Advanced Services
Wireless
Management/diagnostic tools
University of Washington
Computing & Communications
Success Metrics
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10/100 FD connections:
Multicast deployment:
QoS deployment:
Dept’l wireless coverage:
Router center hardening:
Backbone capacity
IPv6 capable routers
xx%
xx%
xx%
xx%
xx%
University of Washington
Computing & Communications
On to Wireless...
University of Washington
Computing & Communications
Wireless Categories
• Wireless by Purpose
– Point-to-Point links
– Access networks
• Wireless by Spectrum
– Infrared
– RF
– Optical
University of Washington
Computing & Communications
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
University of Washington
Computing & Communications
LAN Wireless Standards
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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
University of Washington
Computing & Communications
802.11 ISSUES
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Network Design, esp. Topology
Access control
Security
Compatibility
Interference
Relation to Bluetooth, HomeRF, etc
Obsolescence
University of Washington
Computing & Communications
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.
University of Washington
Computing & Communications
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
University of Washington
Computing & Communications
UW-S Wireless Deployment
• C&C Pilot Project
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Kane Hall, Rm. 130
Mary Gates Hall
Gerberding Hall
Odegaard Undergraduate Library
• Other wireless projects
– CS, C&C, Business, MCIS, ...
University of Washington
Computing & Communications
Pilot Project Objectives
• Provide 11 Mb coverage throughout
selected facilities.
• Allow roaming within facility space.
• Develop suitable policies.
• Gain operational experience.
University of Washington
Computing & Communications
Pilot Project Lessons Learned
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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
University of Washington
Computing & Communications
Wired vs. Wireless Issues
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Server suitability
Performance
Performance variation
Price/Performance
Interference
Technology maturity
Advanced services
Security
University of Washington
Computing & Communications
802.11a: Successor?
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Faster
Shorter distance
More power consumption
Probably won’t replace 802.11b
Probably need WAPs for both
University of Washington
Computing & Communications
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
University of Washington
Computing & Communications
Conclusions
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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.
University of Washington
Computing & Communications
Wireless References
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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