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© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-1111© 2003, Cisco Systems, Inc. All rights reserved.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-2
Module 6
Bridges
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-3
Overview
This chapter discusses wireless bridges as a means of connecting LANs. Bridges are used to connect two or more wired LANs to create one large LAN.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-4
Learning Objectives
•Determine the feasibility of installing a wireless bridge link.
•Explain why a wireless bridge may be a better solution than other alternatives.
•Determine the maximum distance that can be achieved using wireless bridges with given antennas and extension cables.
•Identify steps necessary to protect a wireless bridge installation against a lightning strike.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-5
Key terms
• Root bridge
• Non-Root bridge with clients
• Non-Root bridge without clients
• Repeater AP
• Root AP
• Site-Survey client
• Installation mode
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-6
Bridge Connection
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-7
Bridging Defined
Bridges are used to connect two or more wired LAN’s, usually located within separate buildings, to create one large LAN.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-8
Technology Comparisons
TechnologyTechnology
Recurring CostRecurring Cost
Installation Cost
Installation Cost
Monthly Cost (USD)Monthly Cost (USD)
Dialup or 56K
Dialup or 56K
$25 to $50$25 to $50$0 to $250$0 to $250
Barriers to ImplementBarriers to Implement
Remote locationsRemote
locations
Cable/DSLCable/DSL $0 to $250+$0 to $250+ $25 to $150$25 to $150
E1, T1E1, T1
ReliabilityReliability
FiberFiberPhysical
obstructionsPhysical
obstructions
$250 to $1,000+$250 to $1,000+ $400 to $1000+$400 to $1000+ AvailabilityAvailability
$5,000 to $200,000+$5,000 to $200,000+ $0$0
MicrowaveMicrowave Licensing, Weather
Licensing, Weather
$15,000+$15,000+ $0$0
802.11802.11 $2,000 to $15,000
$2,000 to $15,000 $0$0 InterferenceInterference
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-9
Emerging Markets — Bridging
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-10
Monthly Leased Line OpEx
2 DS1: $600
1 DS3: $5000
TOTAL: $5600
RBOC provides guaranteed level of service via a Service Level Agreement (SLA)
RBOC
DS3DS1
DS1
New remote office
- No DS1 connection available
Traditional WAN Connectivity
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-11
Monthly Line Cost
2 DS1: $600
1 Fractional DS3: $3000
TOTAL: $3600
Wireless Installation Cost
7 350 Series Bridges Installed: $12,500 USD
Pay Back Period: 3 months
New building connected
Self managed
RBOC
22 Mbps
2 Mbps
2 Mbps
5 Mbps
802.11b Connectivity
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-12
Monthly Line Cost
2 DS1: $600
1 DS3: $5000
TOTAL: $5600
Wireless Installation Cost
7 1400 Series Bridges Installed: $40,000 USD
Pay Back Period: 8 months
New building connected
Self managed
RBOC
50 Mbps
14 Mbps
14 Mbps
27 Mbps
802.11a Connectivity
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-13
Role in Radio Network
Role in Radio Network • Determines
functionality within WLAN
• Determines which type of clients will be supported
File Server
BridgeBridge
Access PointAccess Point
PC CardPC CardPCI CardPCI Card
Workgroup Bridge
Workgroup Bridge
Bridge
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-14
Parent – Child Relationship (Root Bridge vs. Non-Root Bridge)
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-15
Root Mode: Access Point vs. Bridge
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-16
Root Bridge
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-17
Non-Root Bridge with Clients
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-18
Non-Root Bridge without Clients
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-19
Bridge Configured as a Root Access Point
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-20
Bridge Configured as a Repeater Access Point
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-21
Bridge Configured as a Site Survey Client
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-22
Distances Limited by 802.11 Specification
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-23
Connecting the 350 Bridge
ss
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-24
BR350—Front Cover LED’s
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-25
802.11b Bridge
Bridge Model Bridge Model
BR350BR350
Note: Distances over 25 miles or 40 Km are very hard to align and install!
Data Rate Data Rate
11 Mbps11 Mbps
11 Mbps11 Mbps
51.7 83.251.7 83.2
20.5 33.0 20.5 33.0
32.7 52.5 32.7 52.5
32.6 52.432.6 52.4
21 dBi Dish21 dBi Dish
41.0 66.041.0 66.02 Mbps2 Mbps
5.5 Mbps5.5 Mbps
Max. Distance
Miles Km
Max. Distance
Miles Km
Optional Antenna Optional Antenna
Standard Cable (6.7 dB/100 ft. loss)
(6.7 dB/30.5 m)
Standard Cable (6.7 dB/100 ft. loss)
(6.7 dB/30.5 m)
1 Mbps1 Mbps
21 dBi Dish21 dBi Dish
21 dBi Dish21 dBi Dish
21 dBi Dish21 dBi Dish
21 dBi Dish21 dBi Dish
50 ft (15.2m)/side50 ft (15.2m)/side
20 ft (6.1m)/side20 ft (6.1m)/side
50 ft (15.2m)/side50 ft (15.2m)/side
50 ft (15.2m)/side50 ft (15.2m)/side
50 ft (15.2m)/side50 ft (15.2m)/side
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-26
802.11b Common Questions
Cisco Aironet BridgeCisco Aironet Bridge How Fast?How Fast?
Max data rateMax data rate
20.5 Miles 33 Km20.5 Miles 33 Km
11 Mbps11 Mbps
5.5 Mbps5.5 Mbps
3.6 Miles 5.8 Km3.6 Miles 5.8 Km
How Far? How Far?
Typical throughputTypical throughput
Yagi antennaYagi antenna
2 Mbps2 Mbps
1.4 Mbps1.4 Mbps
7.3 miles 11.7 Km7.3 miles 11.7 Km
25+ miles 40+ Km25+ miles 40+ Km
Dish antennaDish antenna
Note: All distances may be limited by governing bodies and standards.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-27
Optional 2.4GHz Antennas for Long Range
• 13.5 dBi YagiDistances over
7.3 miles @ 2 Mbps11.7 Km @ 2 Mbps3.6 miles @ 11 Mbps5.8 Km @ 11 Mbps
• 21 dBi Solid DishFor distances up to
25+ miles @ 2 Mbps40+ Km @ 2 Mbps 20.5 miles @ 11 Mbps33 Km @ 11 Mbps
Note: Distances include 50 feet of low loss cable and 10 dB fade margin
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-28
11b Bridge Application: School District
LincolnElementaryYagi
BodeElementaryYagi
RichardsonElementaryYagi
PriceElementaryYagi
Dewitt ElementaryYagi
BolichMiddle SchoolYagi
RobertsMiddle SchoolDish
Weaver-Special EducationDish
High School 2 BridgesOne 12 dBi omniOne Dish Administration
2 BridgesOne 12 dBi omniOne Yagi
U N I V E R S I T YU N I V E R S I T Y
Channel #11
Channel #6
Channel #1
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-29
Lightning
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-30
Lightning Arrestor
Designed to protect LAN devices from static electricity and lightning surges that travel on coax transmission lines
RP-TNC connectors used on all Cisco Antennas
To Antenna
Ground Wire
From RF Device
Lug
LockwasherNut
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-31
Direct Strike Protection
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-32
Coax Connection Sealing
Number one problems with bridges - water in the connectors
Proper sealing is important
Coax Seal is one product that is inexpensive and works great
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-33
Path Loss Considerations
The following are needed to determine coverage · Antenna Gain· Transmitter Power· Receiver Performance· Cable Losses· Environmental Structures
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-34
Calculations of Coverage Performance
Coax Length150 ft (45.7)?
Coax Length100 ft (30.5 m)?
Wants 11 Mbps data rateDistance = 13 miles (20.9 Km)
Towers needed to clear trees andother buildings
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-35
Bridge Range Calculation Utility
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-36
Bridge Distance Calculations (cont.)
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-37
Bridge Distance Calculations (cont.)
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-38
1400 Series Bridge
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-39
1400 Series
High Performance
•Up to 54Mbps throughput
•Outdoor Only
Flexible
•Point to point and point to multi-point bridging
•Multiple mounting and antenna options
Secure
•Enterprise-class security
Feature Rich
•Intelligent Network Services via IOS
AIR-BR1410A-A-K9 AIR-BR1410A-A-K9-N
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-40
1400 Modes
•Root
•Non-Root
•Install-Mode
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-41
Power Injector LR
Converts standard 10/100 baseT Ethernet RJ-45 interface to F-Type connector dual coaxial cable
Power provided over dual coaxial cable with power discovery to protect other appliances
Support for longer cable runs by resetting the 100 meter, 100baseT Ethernet timer, enabling total cable runs of 200 meters.
Surge protection provided at the F-Type connectors to protect infrastructure devices
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-42
802.11a Bridge
Bridge Model Bridge Model
14001400
Note: Distances over 25 miles or 40 Km are very hard to align and install!
Data Rate Data Rate
54 Mbps54 Mbps
9 Mbps9 Mbps
12 xx.0 12 xx.0
23 xx 23 xx
7.5 xx7.5 xx
28 dBi Dish28 dBi Dish
9 xx 9 xx16 Mbps16 Mbps
54 Mbps54 Mbps
Max. Distance
Miles Km
Max. Distance
Miles Km
Optional Antenna Optional Antenna
28 dBi Dish28 dBi Dish
22 dBi Int.22 dBi Int.
22 dBi Int.22 dBi Int.
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-43
Optional 5GHz Antennas for Long Range
Network configurations
•Point to point
•Point to multi-point
Roof, pole, and wall mounting options
5.8 GHz Unlicensed Band Operation
•Rapid deployment and re-commissioning
Operating temp range: -30 to +55 oC
Humidity: 0 to 100%
9 dBi omni (Vertical polarization)
9.5 dBi sector (H or V polarization)
28 dBi dish (H or V polarization)
© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—6-44
Summary
• Identify characteristics of Cisco Aironet 802.11a products.
• Identify characteristics of Cisco Aironet 802.11b products.
454545© 2003, Cisco Systems, Inc. All rights reserved.
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