Cisco AIR-BR1410A-A-K9 - Aironet 1410 Wireless... Quick reference guide

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1Introduction to Technology
The BR1400 Bridges are used to wirelessly connect two networks (usually in different buildings).
When two or more bridges are used, one bridge must be defined as the ROOT BRIDGE. Cisco
wireless bridges default to operation in root bridge mode. In any bridge domain (group of
connected bridges) there should exist only one Root Bridge. Other bridges must be configured to
operate in non-root mode. The NON-ROOT Bridge will initiate a link to the root bridge and all
bridges can subsequently transmit data.
Longer ranges can be activated with appropriate selection of antennas and clear line of sight. It
should be noted that only bridges have this extended range capability. The extended range is
achieved by stretching the timing parameters set forth in the IEEE 802.11 specifications. The
802.11 specification was based on a presumption that a wireless LAN communication link
(keeping in mind this is defining a LOCAL Area Network) would be not more than 1000 feet.
Therefore distances for Access Point to client communication are limited to approximately one-mile
range for quality performance; irrespective of transmit power, cable, and antenna combinations.
This is due to timing restrictions in the 802.11 protocol which synchronize the timing of the
communications to support delays induced by the distance.
1400 Series Wireless Bridge Outdoor Deployment Guide
The purpose for this document is to cover 5 GHz Regulations, 1400 Series Wireless Bridge
Product, interference issues, installation guide, troubleshooting tips and added features. This guide
will help a Network IT professional, who has limited knowledge about RF, but desires to deploy
a wireless Bridge link. This document covers topics that one needs to understand to determine if
the wireless link will work, how to design it, how to install it,optimize the link, maintain and
troubleshoot it.

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Figure 1. Typical Bridge application used to connect different buildings across a
campus or a metro area
Cisco Aironet Bridges support IEEE 802.1d Spanning Tree and can therefore participate in
complex Layer 2 network designs involving redundant or meshed links.
1.1 Channels and Data Rates
IEEE 802.11a defines requirements for a PHY operating in the 5.0 GHz Unlicensed National
Information Infrastructure (UNII) frequency band and data rates ranging from 6 Mbps to 54 Mbps
in seven increments-6, 9, 12, 18, 24, 36, 48 & 54 Mbps. It uses the Orthogonal Frequency
Division Multiplexing-, which is a multi carrier system as compared to single carrier systems.
OFDM allows sub channels to overlap, giving us a high spectral efficiency. The modulation
technique allowed in (OFDM) is more efficient than the spread spectrum techniques use. More bits
are stuffed per second per hertz and provides up to 54 Mbps of data rate to network users.
For US-based 802.11a standard, the 5GHz unlicensed band covers 300 MHz of spectrum and
supports 12 non-overlapping channels. The channel frequencies and numbering defined in IEEE
802.11a start at 5 GHz for United States and each channel is spaced 5 MHz apart. The Figure 2
below shows the center frequency of the channels. The frequency of the channel is 10MHz either
side of the dotted line.
Figure 2. UNII 3 Band

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The 5GHz Band is actually a conglomerate of three Bands in USA: 5.150-5.250(UNII 1), 5.250-
5.350(UNII 2), and 5.725-5.875(UNII 3) GHz. UNII-1 and the UNII-2 bands are contiguous
and are indeed treated by 802.11a as being a continuous swath of spectrum 200MHz wide, more
than twice the size of the 2.4GHz ISM band. This results in a key benefit for 802.11a—the
200MHz wide UNII-1 and UNII-2 bands are divided up into eight non-overlapping channels,
each 25MHz wide.
1.2 Regulations
Outdoor Bridging utilizes UNII 3 band and there are regulatory limitations that apply in this band.
1.2.1 Federal Communications Commission (FCC)Regulations with respect to the
UNII 3 Band
Devices that operate in Unlicensed Bands do not require any formal licensing process, but
operations in these bands still obligate the user to follow regulations. The geographical bodies in
different parts of the world regulate these Bands. WLAN devices must comply withthe local
geographical regulatory domains. The regulatory agencies set the radio emission requirements for
WLAN to minimize the amount of interference a radio can generate or receive from another in the
same proximity. The Federal Communications Commission (FCC) is responsible for framing rules
and regulations for WLAN operations in a particular band in United States. The set of FCC
regulations that apply to WLAN operation in the 5 GHz band is a subset of FCC Part 15
regulations. In addition to US, Australia, New Zealand and various parts of Asia and Oceania also
fall in the FCC regulatory domain.
For latest information please refer to the following URL:
www.cisco.com/go/aironet/compliance
http://www.cisco.com/warp/public/779/smbiz/wireless/approvals.html
1.2.2 Effective Isotropic Radiated Power (EIRP)
The radio energy radiated from an antenna is called the Effective Isotropic Radiated Power (EIRP).
The EIRP is usually expressed in Watts or dBm. To enable fair and equitable sharing of the
unlicensed band, regulatory domains impose maximum EIRP levels.
Directional antennas, such as Yagi and Parabolic dishes have the capability of shaping the signal
from the transmitter so it appears stronger in a particular direction (much the same as the reflector
on a flashlight strengthens a light beam). This is known as antenna gain.
Antenna cables can add loss attenuating the transmitted signal. The longer the cable, the more
attenuation, and the more signal loss in the cable affecting both receive and transmit. Cable
attenuation is dependent upon the grade and manufacturer. Low-loss cable is typically around 6.7
dB per 100 ft (30m) at 2.4GHz.
As the EIRP is a measure of the power out of the antenna, the EIRP must include the antenna gain
and the cable loss together with the power out of the transmitter.

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1.2.3 Power Levels
The UNII-2 band is intended for wireless bridging both for indoor applications as well as short
range outdoor applications. UNII-3 band, with far greater transmit power and antenna gain
allowances is preferable for long range outdoor wireless bridging.
To facilitate this, the regulations allow for connectors and the use of cable and auxiliary antennas for
both of these bands. The effective radiated power allowed in UNII-3 band is 4 watts (36 dBm),
which is much more than the radiated power of 1 watt (30 dBm) allowed in UNII-2 band. Rather,
the UNII-2 band is treated by the Wi-Fi community as being a less-restrictive extension of the
UNII-1 band generally supporting clients and Access Points.
The channel numbers corresponding to the four centre frequencies for UNII-3 band are 149,153,
157 and 161.
Regulatory Domain Frequency Band Channel number Centre frequencies
USA UNII middle band
5.725-5.825 GHz 149 153
157
161
5.745 GHz
5.765 GHz
5.785 GHz
5.805 GHz
Table 1. Channel Numbers for UNII-3 Band
The maximum antenna gain allowed is 6dBi. The transmit power may be reduced to accommodate
higher gain, more directional antennas while staying within the EIRP limits for a particular band. This
is explained in detail, later in this section.
5.15 5.35 5.725
5.25
4Channe
ls
40mW 250mW
1W
UNII-1: Indoor Use, antenna must be fixed to the radio
UNII-2: Indoor/Outdoor Use, fixed or remote antenna
UNII-3: Primarily used for Outdoor Bridging
UNII-1UNII-2UNII-3
Conducted Power
(16dBm
)
(24dBm
)
(30dBm
)
Radiated
Power
Antenna
Gain
6dB
i
6dB
i
6dB
i
22dB
m
30dBm 36dBm
1 W 4W 158mW
5 GHz UNII
Band
4Channe
ls
4Channe
ls

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Figure 3. Conducted and Radiated Power Levels in UNII-1,2 & 3 Bands
Wireless systems are certified as complete systems. In the US, the FCC requires that all antennas
sold by a Wireless vendor be certified with the radio with which they are to be sold. Cisco Aironet
systems are tested and certified for each country using Cisco Aironet components. If amplifiers or
third party antennas are used, then it is likely the entire system must be recertified. Systems
integrators and installers are responsible for FCC compliance or recertification when using third
party equipment.
1.2.4 Other Regulatory Domains
In addition to FCC, other main regulatory domains for operation in 5GHz are European
Telecommunications Standards Institute (ETSI), Japan, China (Mainland China), Israel, Singapore
and Taiwan (Republic of China).
Check the Cisco web site for compliance information and also with your local regulatory authority
on what is permitted within your country.
http://www.cisco.com/warp/public/779/smbiz/wireless/approvals.html
ETSI recommended frequency band for bridging is 5.470 to 5.725 GHz offering almost eleven
channels with the same EIRP rules as FCC. In exchange of this wide spectrum, the ETSI
recommendation mandates the inclusion of two features not currently found in 802.11 products,
Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC). DFS and TPC are the
two functions handled quite well by the HyperLAN2 specification. The IEEE 802.11h standard
covers both DFS and TPC that will apply to the 5 GHz band at a later date.
1.2.5 FCC Regulations regarding EIRP limitations with Point-to-Point & Point-to-
Multipoint Wireless Networks
Wireless bridges can be deployed to establish a direct link between two sites. The network traffic
between the two sites is bridged or forwarded to the other bridge, as if were one network. This is
called a point to point link.
Point-to-multipoint wireless links are an expansion of the point-to-point link in which one
centralized bridge can establish multiple point-to-point links. Using point-to-multipoint connection,
multiple remote sites such as buildings can be linked together into a single logical network. In a
point-to-multipoint architecture, these remote sites are linked to a single root bridge at a centralized
site.
For point-to-multipoint UNII-3 systems, the directional antenna of 6 dBi gain can be used. And if
gain is greater than 6 dBi then the peak transmit power of the device has to be reduced by amount
in dB the directional antenna gain exceeds 6 dBi.

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EIRP = Peak Transmit power (30dBm or 1 Watt) + 6 dBi = 36 dB (4 Watts), a constant.
Point-to-point UNII-3 systems, may employ the transmitting antennas of directional gain up to 23
dBi, without any corresponding reduction in peak transmit power. For antennas with gain greater
than 23 dBi, a dB reduction in output power is required for every corresponding dB increase in
excess of 23 dBi.
EIRP = Peak Transmit power (30dBm or 1Watt) + 23 dBi = 53 dB (200 Watts), a constant.
2BR1400 Wireless Bridge Product Introduction
Cisco’s BR1400 Series, brings about one of the most flexible and feature rich bridging products
Cisco has ever made. It was designed to deployed quick and easily in a multitude of different
environments and for different purposes.
The BR1400 Series Wireless Bridge is designed for building to building Wireless connectivity.
Operating in the 5.8 GHz UNII 3 Band (5725-5825 MHz), derived from the 802.11a standard,
the bridge delivers 6 to 54 Mbps data rates without the need for a license.
This allows anyone to deploy FCC certified bridges anywhere in the US without applying for or
paying for special licenses (note: some restrictions may apply over special areas such as airports
and military bases). This allows for networks to be quickly deployed and then moved if necessary
without any licensing or government reporting. An example would be at an airport or Homeland
Security application where operations need to place cameras and or other data links near critical
areas. By placing a single bridge on top of a tall structure (such as a control tower) and another on
a power/light truck pointing toward the control tower, they have effectively made a full secure link.
Continuing with the scenario as often as required they could move the power/light truck and
effectively move the link through the grounds an endless number of times, each time without
worrying about trenching cables or applying for licensees.
Bridge 1400 is IOS based, and it has the following IOS features:
•Transparent bridging between the wired Ethernet and wireless 802.11a Radio Interface.
•Native Ethernet and 802.1q tagging is supported on both the wired Ethernet and wireless
802.11a Radio interfaces.
•Support for 802.1d Spanning Tree Protocol.
•Support for 802.1q Virtual LAN to work in conjunction with a Switch/Router attached to
the BR1400.
•Support for Port Aggregation Protocol (PagP) and Fast Ether Channel (FEC) providing up
to 100 Mbps of combined bandwidth, by stacking two BR1400 bridges.
•QoS support, 8 transmit priority queues are provided in IOS, with 1 queue per
802.1D/802.1p user priority value for the radio interface.
•IP TOS/DSCP based classifications are supported for classifying voice packets.
•Link level redundancy for P2P using STP.
•Security:

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40-bit and 128-bit WEP encryption
802.1x and LEAP
AAA Radius Server support
Enhanced Encryption Features like TKIP,MIC.
•Voice support for P2P configurations.
•Support for Cisco IP-based protocols like TCP, UDP, TFTP, FTP, ARP, ICMP, CDP,
SNMP, RADIUS, TACACS, SNTP, Telnet and NTP.
•Network management support via three interfaces: SNMP, Web Interface, Telnet/CLI.
•Support for Cisco View network management system.
•IP Address Management, supporting DHCP client/server and DNS client/server
functionality
•Provides diagnostic and statistics information, using any of the management interfaces.
•Installation Mode for aligning the antenna and setting up the ODU at the outdoor site.
2.1 Product Overview
The system consists of a weather proof wireless bridge, a Power Injector-LR, a Power Adaptor,
a grounding block at the building entrance and optionally external antennas. The Bridge and the
external antennas, if used, are installed outdoors. The grounding Block is installed at the building
entrance and the Power Injector LR and DC power supply are installed indoors. The overall
System block diagram is shown in the Figure below.
Figure 4. Schematic of Typical Bridge Installation
2.1.1 Wireless Bridge
The BR1400 wireless bridge includes all the RF and Digital Radio circuitry including four external
interfaces:
1. A pair of 75 ohm F-type coaxial connectors for Power Injector LR interface functioning as
100 Mbps Ethernet communication port and DC power input.
2. Radio interface, which includes a directional captive antenna or an N-type RF connector
for a remote antenna.

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3. RSSI voltage port for antenna alignment
4. Four LEDs providing system status and antenna alignment feedback.
Due to its rugged design, the BR1400 Series Bridge is designed primarily for outdoor deployments.
Unlike other equipment where special care needs to be taken to carefully protect the equipment
from the elements such as wind, rain and other weather conditions such as extreme temperature
gradients on both ends of the spectrum, the BR1400 series was designed with this exact problem in
mind. The BR1400 is plenum rated eliminating the need to have additional NEMA or other
weatherproof enclosures and can operate in temperatures ranging from -22°F all the way to 131°F
without any external temperature influencing devices. The entire unit is designed to withstand and
still operate in severe conditions including very high wind and precipitation of all types.
The BR1400 wireless bridge is available with highly directional captive (built in) antenna. The gain
of captive antenna is 22.5 dBi. We also have an option for connecting external antennas under a
different SKU where it provides an N-type RF connector for interfacing to various external
antennas for greater range and flexibility.
Figure 5. AIR-BR1410A-A-K9 and AIR-BR1410A-A-K9-N
Please note the Radome provides an environmentally sealed enclosure and is not removable from
the housing. Therefore, you should plan in advance about what type of network you want to
deploy, as these SKUs are not interchangeable in the field. If you wish to use high gain antennas for
longer range or perhaps an Omni antenna for multi-point operation you may need to order the
SKU on the right of the picture above.
In addition to the conventional role of the radio in the bridge as “Root” or “Non Root”, BR1410
has more roles in radio network which facilitates the installation and alignment. Observable LEDs
and the voltage port can be used for alignment, so one does not need a laptop or any other
conventional tool for installing these bridges. Please refer to the documentation for BR1410
available on our website:
http://www.cisco.com/en/US/products/hw/wireless/ps5279/index.html
2.1.1.1 Antennas for the BR1400

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The antennas listed here are available as optional remote antennas for the BR1400. The Beamwidth
and the gain of the antennas are mentioned in the Tables below.
Part Number Description
AIR-AN58G09VOA-N5.8 GHz 9 dBi Non-Diversity Omni Vertical Polarization Ant with N-Type Connector
AIR-AN58G10SSA-N5.8 GHz 10 dBi Non-Diversity Symmetric Sector Antenna with N-Type Connector
AIR-AN58G28SDA-N5.8 GHz 28 dBi Non-Diversity Symmetric Dish Antenna with N-Type Connector
Table 2. External Antennas for BR1400 Wireless Bridge
Antenna Horizontal Beamwidth (degrees) Vertical Beamwidth (degrees)
Integrated (Captured) 12.0 10.0
Omni 360 6 +/-0.5
Sector 60.0, minimum 60.0, minimum
Dish 5.7 6.0
Table 3. Beamwidths of the Antennas
Please refer to the installationsection in the BR1400 manual for details about which antennas may
be used.
2.1.2 Power Injector-LR (Long Reach)
The Power Injector-LR is a self-contained functional unit suitable for indoor installation. It provides a
100 Base-T Ethernet link between the In-building LAN and the outdoor wireless unit (ODU). The
main function of Power Injector is to provide power onto the Ethernet connection to the ODU. The
Ethernet connection to the ODU is via two 75-ohm coax cables, the coaxial cables can be RG6,
RG59 or higher quality 75-ohm cable with a maximum length up to 100 meters. The indoor connection
to the local LAN uses standard category 5 twisted pair copper and can provide connectivity at lengths
up to 100 meters. The Power Injector is poweredby the power adapter and supplies the DC voltage
into both coaxial cables powering the ODU.
Please note that these coaxial cables do not carry any RF (radio frequency) energy. All the RF is
contained within the Outdoor Unit or Bridge.
The Power Injector has three externalinterfaces:
1. RJ45 connector for internal 100 baseT LAN interface.
2. A pair of 75 ohm F-type coaxial connectors for 100 baseT interface to the wireless bridge
(ODU).
3. DC power connector interfaced to the power adapter.

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Three LEDs are included on the front power injector as shown in the figure below. They indicate
Ethernet activity, Injector Status and Uplink activity. There is a fourth LED (on the side of the box)
indicating DC power from the power adapter.
Figure 6. Power Injector-Long Reach
2.1.3 Power Adaptor
Power Adaptor provides +48V DC to the power injector. It is rated to deliver 60 W of DC
power. It has two interfaces:
1. DC output through a short cable via a barrel style power connector .25 OD (center
positive) interfacing to Power Injector
2. Universal AC input connector to be plugged into an AC power cord.
2.1.4 Grounding Block
Grounding block (Cisco provided) should be installed inline with 75 ohm coax cables at the
building entrance providing lightning protection. It has straight through F-connectors where the
shield is connected to the body of the block. This type device is commonly available for CATV
type usage by third party vendors.

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2.2 Bridge 1400 Low Power version
There are different SKUs with different power levels for different parts of the world in accordance
with the regulatory domains respective to these countries.
Refer to the following URL:
www.cisco.com/go/aironet/compliance
We can broadly classify the SKUs as High Power and Low Power versions. The SKU for
America and Canada is a High Power version with ability to radiate at maximum output power of
24 dBm. The part numbers for these two SKUs are AIR-BR1410A-A-K9 and AIR-BR1410A-
A-K9-N as discussed earlier.
In low power version we have three different SKUs as below:
1. AIR-BR1410A-E-K9
•Available Tx Power Settings: 4 & 7 dBm
•Antenna Gain: 22.5 dBi
•Anticipated Countries: Ireland, China, Malaysia, Venezuela
2. AIR-BR1410A-K-K9
•Available Tx Power Settings: 12, 15, 18, 21, & 22 dBm
•Antenna Gain: 20 dBi
•Anticipated Countries: Korea
3. AIR-BR1410A-Z-K9
•Available Tx Power Settings: 4, 7, 8, 9, 10, & 13 dBm
•Antenna Gain: 22.5 dBi
•Anticipated Countries: Australia and New Zealand
All these Low power SKUs operate in the same frequency band as high power SKUs i.e,
complete UNII 3 band. Should the installer wish to deploy point-to-multipoint networks using
Omni or Sector Antennas in these countries then High power SKU AIR-BR1410A-A-K9-N
may be ordered, check with your regulatory agency.
High gain dish antenna with 28 dBi is not supported in any of the above countries.
The outdoor range calculator can be used to determine distances with these Low power
SKUs.
3Applications
Although we have covered several features of the BR1400 Series, we will now discuss some of the
features and functionality used in major Bridging applications.
3.1 VLANs
A VLAN is a group of end stations with a common set of requirements, independent of their
physical location. A VLAN has the same attributes as a physical LAN but permits you to group
end stations together even if they are not located physically on the same subnet.

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802.1q Virtual LAN support is provided to work in conjunction with the Switch/Router attached to
the 1400 series wireless bridge. Both the wired Ethernet and wireless Radio interface supports
VLAN Trunking. Native Ethernet and 802.1q tagging is supported on both the Ethernet and Radio
interfaces.
ISL tagging, VTP and DTP are not supported in BR1400. The BR1400 treats VTP message like
any other multicast message and Transparently Bridgesit across.
Thus, the Bridge participates in the 802.1d (spanning-tree) process of bridging two networks
together. You extend VLANs into a wireless LAN by adding IEEE 802.11Q tag awareness to the
bridge. VLAN 802.1Q trunking is supported between root and non-root bridges through the
bridges’ primary SSID.
The basic wireless components of a VLAN consist of two or more bridges communicating using
wireless technology. The bridge is physically connected through a trunk port to the network VLAN
switch on which the VLAN is configured. The physical connection to the VLAN switch is through
the bridge’s Ethernet port.
Figure 7. VLANs trunked through the wireless bridge links
In fundamental terms, the key to configuring a bridge to connect to a specific VLAN is by
configuring its SSID to recognize that VLAN. Since VLANs are identified by a VLAN ID, it
follows that if the SSID on a bridge is configured to recognize a specific VLAN ID, a connection to
the VLAN is established.
The bridge supports only one infrastructure SSID. You should assign that SSID to the native
VLAN. For more information, please consult the VLAN deployment Guide at this URL:
http://www.cisco.com/en/US/products/hw/wireless/ps430/prod_technical_reference09186a00801
444a1.html

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Figure 8. VLAN CONFIGURATION
The main steps to configure the VLANs are:
1) Enable 802.1q trunking on the wired network: On either side of the Link you should console into
the Ethernet port of the Switch to which Bridge is connected and give the following commands:
Interface FastEthernet0/1
Switchport trunk encapsulation dot1q
Switchport mode trunk
Please note that you must have 100 Mbps Ethernet connections between the switch and
the Bridge.
2) Enable 802.1q trunking on the Bridges: Specify the VLAN-id X as the native VLAN on the
root and non root bridges by going into the GUI services and clicking on VLAN.
VLAN 11
802.1Q Trunk
100Mbps,
NATIVE VLAN
VLAN 12
VLAN 12
VLAN 14
Root
Switch_1 Switch_2
Non-Root
Station_A
Station_C
Station_B
Station_
D
Station_E
VLAN 11
Infrastructure ssid: native VLAN

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Figure 9. Screenshot for VLAN configuration
3) Mapping: Map the native VLAN to the Bridge SSID. For this use the GUI interface and go to
Security and click on SSID Manager. Map the SSID to VLAN X.
Figure 10. Screenshot for VLAN configuration

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4) Add the VLANs: Add the VLANs defined on the switches to the Root and Non Root Bridges.
Like for the above figure, VLANs 11, 12 and 14 have to be added on the Bridges as well, so that
these VLANs can be trunked through the wireless link.
3.2 QoS
Implementing QoS in your wireless link makes network performance more predictable and
bandwidth utilization more effective. By using QoS feature you can prioritize a specific type of
traffic instead of making it a purely FIFO (first in, first out). This is due to the fact that voice/video
traffic when subject to delays causes very unfavorable behavior in phone conversations (major lags
or even dropped phone calls). This is also true with other types of traffic such as video traffic
(which is what we will be testing here in this situation).
The following are the objectives of the QoS feature supported in 1400 bridge:
•Provide 802.1p priority bits and 802.1q VLAN tag based QoS
•Provide priority services for VOIP traffic, based upon IP TOS/DSCP
The bridge can only classify traffic based on IP TOS (Type of service bits in IP protocol header)
Precedence and DSCP (differentiated services code point) values and put it into the correct priority
queues. It has 8 priority queues corresponding to eight 802.11E priority values. The CoS values
associated with the eight priority queues are the same as the 802.1d
User priority values that are carried in an Ethernet frame, an 802.1q priority tag or an 802.1q
VLAN tag. The CoS value is used to select the appropriate 802.11 transmit queue.
The bridge uses the radio traffic class definitions to calculate back off times for each packet. As a
rule, high-priority packets have short back off times. The default values in the Min and Max
Contention Window fields and in the Slot Time fields are based on settings recommended in IEEE
Draft Standard 802.11e.
We can modify the CwMin and CwMax values depending upon the type of the network and our
needs.
QoS works even with packet concatenation enabled.
The steps to configure QoS are:
1) First create a QoS policy. Go to services in GUI interface and define a policy.

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Figure 11. Screenshot for QoS configuration
2) Apply the policy: You can apply the policy to the VLAN configured on the bridge. If you
do not use VLANs on your network, you can apply your QoS policies to the bridge’s
Ethernet and Radio ports.
Figure 12. Screenshot for QoS configuration

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3.2.1 Voice over IP
Using the QoS feature, voice traffic can be prioritized by defining a policy and assigning that policy
to the VLAN carrying the voice traffic.
At this time, the 1400 series Bridge supports voice only in P2P links. Voice in a P2MP
configuration is limited and has not been fully tested yet, however; it will support some number of
simultaneous voice calls as it has the same QoS mechanisms as point to point networks. Keep in
mind, since there is no over the air QoS coordination between end points, it will not be as efficient
as point to point network. Voice in P2MP networks will be possible when PCF mode is
implemented down the line.
The maximum number of voice lines for P2P links in the table below. The number of voice calls
shown in the table has been taken along with the data traffic running in the network. Number of
voice lines has been calculated by setting a maximum jitter bound of 25 ms. This cannot be
guaranteed for 6 and 9 mbps rates. For P2P links supporting voice those rates needs to be
disabled or the voice quality will be poorer depending on the rest of the network architecture.
Rate (Mbps) # Calls G.711 # Calls G.729
54 15 44
48 15 44
36 15 44
24 15 44
18 15 44
12 15 44
9 NO SUPPORT NO SUPPORT
6 NO SUPPORT NO SUPPORT
Table 4. Maximum number of calls for P2P for G711 and G729 codec (jitter<25 ms)
3.3 Security
Security is a major part of any enterprise deployment and as such Cisco has spent quite a bit of
time on ensuring the security of not only the wireless links as a whole but also the Bridge itself.
Multiple types of security levels are available on 1400 Series Bridge.
Configuring your own SSID on the 1400 Bridges provides a rudimentary level of security. 1400
Bridge also provides different type of encryptions on the data going across the link, like Static
Wired Equivalent Privacy (WEP), Dynamic WEP using LEAP, TKIP (Temporal Key Integrity
Protocol) and MIC (Message Integrity Check). 1400 wireless bridge supports Cisco Wireless
Enhanced Authentication Protocol (LEAP). LEAP is a Cisco proprietary implementation
conforming to the IEEE 802.1x Draft Security Standard for port-based network access control.
LEAP authenticates the user and assigns a new WEP key every time a client associates or

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reassociates with an Access Point or a Bridge. 1400 Bridge can behave as a LEAP client in slave
mode (Non Root) or LEAP authenticator in Master mode (Root) as shown in the figure below.
Figure 13. Leap in a bridge link
LEAP requires a LEAP compliant Remote Authentication Dial-In User Service (RADIUS) server
such as Cisco Secure ACS 2.6 (or later) to operate. LEAP is a mutual authentication scheme (of
Client and Radius Server). The challenge-response mechanism uses the user’s password as the
shared secret. In a Microsoft Network environment, a user’s Domain id and password can be
used. Leap can be used with wide variety of platforms. No native EAP support is currently
available on Legacy operating systems.
The main steps to set up the bridge link with Leap are:
1) Configure the ACS server with a unique IP address. Make sure that you can ping ACS
server from the Root Bridge.
2) Configure the ACS server with an AAA client with the Root Bridge’s IP address and the
appropriate shared secret password. Please refer to the LEAP configuration Guide for
setting up the ACS. The Link is:
http://www.cisco.com/warp/public/cc/pd/witc/ao1200ap/prodlit/wrsec_an.htm
3) Add a user account (user-id and password) on RADIUS server (ACS) for Non Root
authentication. Example: user-id = non-root, password=non-root.
4) Enter the parameters for RADIUS server in the Root Bridge. Use the GUI interface and go
to Server Manager in the security section to do this.

Copyright © 2004Cisco Systems, Inc. All rights reserved.
Page 19 of 53
Figure 14. Screenshot for configuring Security
5) Configure Non Root Bridges with a user-id/password (for example: non-root/non-root) for
LEAP authentication to the root bridge using ACS. In GUI interface go to SSID manager
in Security section to do this.

Copyright © 2004Cisco Systems, Inc. All rights reserved.
Page 20 of 53
Figure 15. Screenshot for configuring security
6) After completing the above steps, view the association table of the root bridge to ensure all
non root bridges are associated.
7) Enable TKIP & MIC if you want enhanced encryption in your link.
4Feasibility Study
This section will provide the reader with an understanding of what is required to determine if a
successful bridge link can be accomplished.
When determining the suitability of a successful bridge link, one needs to define how far the Bridge
link is expected to transit and at what radio data rate. Very close bridge links one Kilometer or less
are fairly easy to achieve assuming there are no obstructions referred to in radio jargon as a “Clear
Line Of Sight” or LOS.
If both buildings are very close, a link might be attained from a window by using one of the upper
floors of the building avoiding the need to install a bridge outdoors. This might be fine for a
temporary event or in a pinch to get a link up when time or weather conditions don’t allow for a
more permanent solution. Keep in mind some windows can have metallic flakes inside the glass for
tinting or perhaps conductive gas for insulation to prevent fogging such materials may impede
(attenuate) the radio signal preventing such a link.
Tip: Links through glass are not a preferred method but could work for very short links.