ch. 6 - bridges cisco fundamentals of wireless lans version 1.1 rick graziani cabrillo college

Ch. 6 - Bridges

Cisco Fundamentals of Wireless LANs version 1.1

Rick Graziani

Cabrillo College

Rick Graziani graziani@cabrillo.edu 2

Overview

• Designed to connect two or more networks, typically located in different buildings, wireless bridges deliver high data rates and superior throughput for data-intensive, line-of-sight applications.

• The bridges connect hard-to-wire sites, noncontiguous floors, satellite offices, school or corporate campus settings, temporary networks, and warehouses.

• The high-speed links between the wireless bridges deliver throughput many times faster than E1/T1 lines for a fraction of the cost, thus eliminating the need for expensive leased lines or difficult-to-install fiber-optic cable.

802.11a

Bridge Connection

Bridging Defined

• Bridges are used to connect two or more wired LAN’s, usually located within separate buildings, to create one large LAN.

Rick Graziani graziani@cabrillo.edu

Technology Comparisons

TechnologyTechnology

Recurring CostRecurring Cost

Installation Cost

Monthly Cost (USD)Monthly Cost (USD)

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

Monthly Leased Line OpEx

2 DS1: $600

1 DS3: $5000

TOTAL: $5600

RBOC provides guaranteed level of service via a Service Level Agreement (SLA)

DS3DS1

New remote office

- No DS1 connection available

Traditional WAN Connectivity

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

22 Mbps

2 Mbps

5 Mbps

802.11b Connectivity

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

50 Mbps

14 Mbps

27 Mbps

802.11a Connectivity

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

Bridge

Introduction

• The BR350 is sometimes called the multifunction bridge.

Bridges

• Cisco bridges can be controlled and configured though command line and Web interfaces.

• Management can also be done through traditional protocols like SNMP.

Bridge roles in the network

• The Cisco bridges can be configured to operate in different modes.

• The BR350, or multifunction bridge, has the same receiver sensitivity, power levels, and capabilities, as the Cisco Aironet APs with .11b radio chips.

Parent-Child Relationship: Root - Non-Root

• Root Access Point—Use this setting to set up the bridge as a rugged access point connected to the wired LAN. When you select Access Point, the bridge's Spanning Tree Protocol (STP) function is disabled.

Root Access Point

• Root bridge—One bridge in each group of bridges must be set as the root bridge. A root bridge can only communicate with non-root bridges and other client devices and cannot associate with another root bridge.

Root Bridge

• Non-Root Bridge w/Clients—Use this setting for non-root bridges that will accept associations from client devices, and for bridges acting as repeaters. Non-root bridges can communicate with other non-root bridges, root bridges, and client devices.

Non-Root Bridge with Clients

• Non-Root Bridge w/o Clients—Use this setting for non-root bridges that should not accept associations from client devices. A bridge set to Non-Root Bridge w/o Clients will only communicate with a root or non-root bridge.

Non-Root Bridge without Clients

• Repeater Access Point—Use this setting to set up the bridge as a rugged repeater access point. A repeater access point is not connected to the wired LAN; it is placed within radio range of an access point connected to the wired LAN to extend the range of your infrastructure or to overcome an obstacle that blocks radio communication. When you select Repeater Access Point, the bridge's STP function is disabled.

Repeater Access Point

Power Options

Distances Limited by 802.11 Specification

BR350—Front Cover LED’s

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

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

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

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.

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

802.11b 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

Lightning

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

LockwasherNut

Direct Strike Protection

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

Path Loss Considerations

The following are needed to determine coverage · Antenna Gain· Transmitter Power· Receiver Performance· Cable Losses· Environmental Structures

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

LED indicators

• When the bridge is powering on, all three LEDs normally blink.

• After bootup, the colors of the LEDs represent the following: – Green LEDs indicate normal activity. – Amber LEDs indicate errors or warnings. – Red LEDs mean the unit is not operating correctly or is being

upgraded.

Connecting to the Bridge

• There are 3 basic GUI interfaces depending on the bridge image: – IOS 1400 – VxWorks BR350 – SOS WGB350

1400 with IOS GUI

BR350 with VxWorks GUI

WGB350 with SOS GUI ad SOS Menu

Resetting the Bridge

• Resetting the Cisco bridges depends on the model. • The BR350, can be reset via the console, telnet, or browser

connection. – If the password is unknown, then the console reset method is

required. – The console port on the BR350. – The :resetall command can be used after rebooting the bridge,

however the command must be entered within 2 minutes of rebooting.

• The 350 Series Workgroup Bridge or the 1400 series bridge can be reset to default values via the Reset button, telnet, or browser connection.

Default Settings for BR350 and 1400

Default Settings for WGB 350

Basic Configuration

Will will not use or discuss all of the configuration options and features.

BR350 Home Page (Summary Status)

BR350 Map Link

• The Map link opens the Map window, which contains links to every management page.

• The Map window can be used to jump quickly to any system management page, or to a map of the entire wireless network

BR350 Network Link

BR350 Associations Link

BR350 Setup Link

• The Setup link displays the Setup page, which contains links to the management pages with configuration settings.

BR350 Logs Link

BR350 - Basic Configuration

• Connect just like an AP, suggest wired GUI.

• Remember to set the IP address on your Ethernet NIC.

Root Bridge and Non-Root Bridges

Non-Root Bridge without ClientsRepeater Bridge

Bridge as Root Access Point

Bridge as Repeater Access Point

Root Radio Identification configuration

• The current IP subnet mask displayed under the setting shows the IP subnet mask currently assigned to the bridge. This is the same subnet mask as the default subnet mask unless DHCP or BOOTP is enabled. If DHCP or BOOTP is enabled, this is the subnet mask used by the DHCP or BOOTP server.

• You can also enter this setting on the Express Setup page.

Root Radio Identification Page

• Primary Port Settings: Two options allow for the designation of the radio port as the primary port on the bridge:

• Primary Port? The primary port determines the MAC and IP addresses of the bridge. – The default primary port of the bridge is the Ethernet port. – The Ethernet port is connected to the wired LAN, so this setting is

usually set to no. – Select no to set the Ethernet port as the primary port. – Select yes to set the radio port as the primary port.

• Adopt Primary Port Identity? – Select yes, to adopt the primary port MAC and IP addresses for the

radio port. – Select no to use different MAC and IP addresses for the radio port.

Bridges acting as root units adopt the primary port settings for the radio port.

• When putting a bridge in standby mode, select no for this setting.

Root Radio Hardware configuration

• Similar to an AP.

Root Radio Hardware configuration

Ethernet Identification configuration

• Addressing is similar to Root Radio options

Ethernet Hardware configuration

Configuring time services

Configuring boot services

Configuring name services

Configuring routing services

• Manage Installation Keys is used to read specifications of the software license and to install a new license.

• Manage System Configuration is used to restart the device, download a configuration file, or reset settings to factory defaults.

• Distribute Configuration to other Cisco Devices is used to send the configuration of the device to other Cisco Aironet devices on the network.

• Distribute Firmware to other Cisco Devices is used to send a new firmware version to other Cisco Aironet devices on the network.

Distribute Firmware to Other Cisco Devices

Hot Standby Management

1400 Series Bridge

801.11a wireless bridge

Overview

• The Cisco Aironet 1400 Series Wireless Bridge is a high-performance 801.11a wireless bridge designed to connect multiple LANs in a metropolitan area.

• Designed to be a cost-effective alternative to leased lines, it is engineered specifically for harsh outdoor environments . The features of the 1400 include:

Overview

• Support for both point-to-point or point-to-multipoint configurations • Support data rates up to 54 Mbps • Enhanced security mechanisms based on 802.11i standards • Rugged enclosure optimized for harsh outdoor environments with

extended operating temperature range • Integrated or optional external antennas for flexibility in deployment

Overview

• Data rates of 54 Mbps can be enabled for point-to-point links up to 7.5 miles, and for point-to-multipoint links up to 2 miles.

• Aggregate throughput can be obtained in excess of 28 Mbps.

• Also, by using higher gain antennas or lower data rates, ranges in excess of 20 miles point-to-point can be covered.

Models and options

• There are two options for ordering the Cisco Aironet 1400 Series Wireless Bridge: – Cisco Aironet 1410 Wireless Bridge with 22.5 dBi Antenna, FCC

Config – Cisco Aironet 1410 Wireless Bridge with N-Type Connector, FCC

Config

Models and options

Components and accessories

Cisco Aironet Power Injector

Mounting Kit

IOS features

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

9 xx 9 xx16 Mbps16 Mbps

54 Mbps54 Mbps

Max. Distance

Miles Km

Max. Distance

Miles Km

Optional Antenna Optional Antenna

22 dBi Int.22 dBi Int.

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)

Bridge Range Calculation Utility

Bridge Distance Calculations (cont.)

Ch. 6 - Bridges

Cisco Fundamentals of Wireless LANs version 1.1

Rick Graziani

Cabrillo College

ch. 6 - bridges cisco fundamentals of wireless lans version 1.1 rick graziani cabrillo college

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