Cisco 2911 Configuration Guide

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Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Chapter Configuring Radio Settings
Disabling and Enabling Aironet Extensions
The optional parameters can be configured independently or combined when you do not want to use the
defaults, as shown in the following examples:
(config-if)# probe-response gratuitous period 30
(config-if)# probe-response gratuitous speed 12.0
(config-if)# probe-response gratuitous period 30 speed 12.0
Use the no form of the command to disable the GPR feature.
Disabling and Enabling Aironet Extensions
By default, the wireless device uses Cisco Aironet 802.11 extensions to detect the capabilities of
Cisco Aironet client devices and to support features that require specific interaction between the wireless
device and associated client devices. Aironet extensions must be enabled to support these features:
• Load balancing—Wireless device uses Aironet extensions to direct client devices to an access point
that provides the best connection to the network on the basis of such factors as number of users, bit
error rates, and signal strength.
• Message Integrity Check (MIC)—MIC is an additional WEP security feature that prevents attacks
on encrypted packets called bit-flip attacks. The MIC, implemented on the wireless device and all
associated client devices, adds a few bytes to each packet to make the packets tamper-proof.
• Cisco Key Integrity Protocol (CKIP)—Cisco’s WEP key permutation technique is based on an early
algorithm presented by the IEEE 802.11i security task group. The standards-based algorithm,
Temporal Key Integrity Protocol (TKIP), does not require Aironet extensions to be enabled.
• World mode (legacy only)—Client devices with legacy world mode enabled receive carrier set
information from the wireless device and adjust their settings automatically. Aironet extensions are
not required for 802.11d world mode operation.
• Limiting the power level on associated client devices—When a client device associates to the
wireless device, the wireless device sends the maximum allowed power level setting to the client.
Disabling Aironet extensions disables the features listed above, but it sometimes improves the ability of
non-Cisco client devices to associate to the wireless device. Aironet extensions are enabled by default.
To disable Aironet extensions, follow these steps, beginning in privileged EXEC mode.
SUMMARY STEPS
1. configure terminal
2. interface dot11radio {0| 1}
3. no dot11 extension aironet
4. end
5. copy running-config startup-config
Step 5
speed
{[6.0] [9.0] [12.0] [18.0] [24.0]
[36.0] [48.0] [54.0]}
(Optional) Sets the response speed in Mbps. The default value
is 6.0.
Step 6
end Returns to privileged EXEC mode.
Step 7
copy running-config startup-config (Optional) Saves your entries in the configuration file.
Command Purpose

Cisco 2911 Specifications

General

Ethernet LAN	Yes
Cabling technology	10/100/1000Base-T(X)
Networking standards	IEEE 802.1Q, IEEE 802.1ag, IEEE 802.3, IEEE 802.3ab, IEEE 802.3af, IEEE 802.3ah, IEEE 802.3u
Ethernet LAN data rates	10, 100, 1000 Mbit/s
Ethernet interface type	Gigabit Ethernet
DHCP client	-
Routing protocols	BGP, EIGRP, OSPF
Supported protocols	IPv4, IPv6, IS-IS, IGMPv3, PIM SM, SSM, DVMRP, IPSec, GRE, BVD, MPLS, L2TPv3, PPP, MLPPP, MLFR, HDLC, RS-232, RS-449, X.21, V.35, EIA-530, PPPoE, ATM
USB version	2.0
RS-232 ports	1
Expansion slots	4 x EHWIC 2 x DSP 1 x ISM
USB ports quantity	2
Ethernet LAN (RJ-45) ports	3
Firewall security	Cisco IOS
Input current	2.2 A
AC input voltage	100 - 240 V
Power source type	AC
AC input frequency	47 - 63 Hz
Power consumption (typical)	50 W
Product color	Black
Rack capacity	2U
Operating altitude	0 - 4000 m
Non-operating altitude	0 - 4570 m
Storage temperature (T-T)	-40 - 80 °C
Operating temperature (T-T)	0 - 40 °C
Storage relative humidity (H-H)	5 - 95 %
Operating relative humidity (H-H)	5 - 85 %
Safety	UL 60950-1, CAN/CSA C22.2 No. 60950-1, EN 60950-1, AS/NZS 60950-1, IEC 60950-1
Electromagnetic compatibility	47 CFR, ICES-003, EN55022, CISPR22, AS/NZS 3548, VCCI V-3, EN 300-386, EN 61000, EN 55024, CISPR 24EN50082-1

Weight and Dimensions

Depth	304.8 mm
Width	438.2 mm
Height	88.9 mm
Weight	8200 g