Questions tagged [ieee-802.11]

For questions about the IEEE 802.11 series of protocols, also known as Wi-Fi. This tag should be used when asking about enterprise or corporate Wi-Fi networking questions. Questions about home wireless networks are off topic.

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19
votes
2answers
6k views

Can a probe request be answered on a different channel?

I am monitoring the 802.11 traffic in my network, and especially the active probing from my smartphone. I am sending Probe Requests for certain hidden SSIDs, but also an Undirected Probe Request, ...
18
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4answers
24k views

Cisco APs ignore DHCP Option 43 and use CAPWAP UDP broadcasts

Background I am trying to redeploy Cisco 1242 LWAPs on new Cat4507R+E switches, which means the IP address of the WLC is changing for that LWAP. For some reason, I have to configure ip helper-...
14
votes
5answers
9k views

Do WiFi and IEEE 802.11 mean the same thing?

I would like to know if WiFi can be generally referred to IEEE 802.11 standard in the context of IoT/machine-to-machine communications or the latter can be referred to as a more general family. I have ...
13
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3answers
33k views

Mac-flap due to roaming clients on wireless

We are running an Aerohove wireless network (controller-less).. I occasionally get mac-flaps within the VLAN tied to a SSID. I know this is coming from a roaming client.. The problem is that the ...
13
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4answers
1k views

Is a wireless only network (for end users) a viable option?

We are constructing a new building, and our CIO is pushing for a solution where he doesn't have to spend the money on copper runs to all the user stations and wants to use wireless only for this ...
13
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2answers
2k views

Simulating a poor network [closed]

I'd like to set up a poor wifi network in my office for developers to test on. What is the best way to simulate real world crappy wifi? High latency? Dropped packets? low bandwidth?
12
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3answers
5k views

Identifying a Cisco access point post-install

We have about 50 Cisco 1242 access-points and we're managing them with a Cisco 4404 Wireless Lan controller. The guy who installed the APs did not assign a location to the access points in the ...
11
votes
1answer
11k views

Four layer-2 addresses in 802.11 frame header

I am new to wireless LAN. I see that it has 4 addresses in the frame header. In case of a Wired Ethernet, there are only 2 mac addresses, the source and the destination (which is essentially the ...
11
votes
1answer
21k views

WLC - How to disable 2.4Ghz

Is there any way I can disable the 2.4Ghz and just leave 5.0Ghz channel enabled on a per WLAN (SSID) basis? Or the only way is to disable the AP's radio and leave 5Ghz enabled?
10
votes
2answers
14k views

How do wifi clients detect SSIDs from APs?

How can my wifi board detect wireless networks that are in range? What protocol is used to communicate with the devices in the area to announce a wifi AP? Does every router transmit on its own ...
10
votes
3answers
4k views

Why is my UDP broadcast wireless communication capped at 1 MB/s?

I am trying to implement Network Coding over a meshed network. Therefore I need to send packets to several destinations, this is way I am using Broadcast packets. But I can not understand why this is ...
10
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4answers
3k views

Raw-Ethernet Frames

Recently I was puzzled by the following articles about Raw-Ethernet frames: RAW ethernet vs. UDP Message Passing Using Raw Ethernet Frames Briefly, both of them discusses that it is possible to ...
9
votes
1answer
3k views

Is wifi power consumption related to password length

For wifi the Max password length is 63 characters. When I choose such a long password will this lead to notably higher power consumption of the network device (router, smartphone, ...)? I would guess ...
9
votes
2answers
27k views

Can I truly multicast over WIFI?

Am streaming UDP over wifi (5ghz) - approx 1.5k/packet... trying to stream to ~10 devices simultaneously, with extremely low latency.. As I understand Wifi, it can never true multicast, as each ...
9
votes
3answers
4k views

Does varying the angle of omni directional antennas affect connection quality between WiFi APs?

I use Cisco access points AIR-CAP1552E to connect buildings via WiFi, 802.11a/n (5 GHz). Normally, they are mounted upright, with three three omni directional antennas at the bottom. Now I consider a ...
8
votes
5answers
521 views

Is it feasible to install two enterprise WIFI access points without training?

Have a background in computer software, but do not have any formal training in networking and hardware. We got a quote from a local IT company that is more than we are able to pay. They want $900 ...
8
votes
4answers
3k views

Cisco 1260 AP no longer responds to ping, ssh after upgrade to latest 15.x firmware

I have a 1260 AP that I upgraded this morning. Prior to the upgrade, the system permitted ssh and would respond to pings on the network, however now it does not respond. I hooked up a serial cable ...
8
votes
3answers
3k views

Will Linux send the ARP gratuitous or ARP probe (defined in RFC 5227) [closed]

I did an experiment to check if Linux will send the gratuitous ARP or ARP probe before using the target IP. The experiment scenario is as follows: There are two Linux computers, both connected to ...
7
votes
2answers
592 views

How is the Groupwise Transient Key used in WiFi networks?

In Wifi WPA, I understand that during association, a 802.11 client and AP negotiate a Pairwise Transient Key (PTK), using which the Groupwise Transient Key(GTK) is provided to the station. I ...
7
votes
2answers
130 views

How the packet is routed between two host from same sub-net and associated with same AP?

Given host 'A' and 'B' have IP 10.10.0.5 and 10.10.0.8 respectively, the sub-net mask for both are 255.255.255.0, both 'A' and 'B' are associated and connected to the same AP, and the AP is connected ...
7
votes
1answer
757 views

Why do we have authentication before association in 802.11

Why does client authenticate before associating with the AP. What does open system authentication even achieve. I fail get an accurate reason from my web searches. Best reason I do get is unlike wired ...
7
votes
1answer
1k views

DCF and PCF in Wifi-networks

I am studying, trying to learn how DCF (Distributed Coordination Function) and PCF (Point Coordination Function) works as access methods in WiFi, and how they relate to infrastructure vs ad hoc ...
7
votes
1answer
2k views

AP's at remote faciltiy will not join local controller

I currently have a WLC 4404 running 7.0.240.0. Management Interface IP is 10.128.55.10. AP-management interface is 10.128.55.15. Remote facility (facility A) has a VLAN created for wireless (455) ...
6
votes
2answers
5k views

Why are 802.11n data rates for 5GHz not faster than 2.4GHz?

Same protocol, different frequency. So why does 802.11 spec not take advantage of the higher frequency to obtain higher data rates?
6
votes
2answers
462 views

Why do wireless signals interfere with themselves regularly?

I come from a computer science background but physics is not presently one of my strengths. I've been reading some research regarding multi-hop routing of wireless (ad-hoc) networks such as this paper ...
6
votes
2answers
3k views

Does Windows support PEAPv1/EAP-GTC?

We are running a wireless infrastructure using PEAPv1/EAP-GTC. Our Windows machines can't seem to connect to wireless access points, what is happening?
6
votes
1answer
6k views

Why doesnt Bluetooth Low Energy interfere with Wifi

so the BLE advertising channels are located at 2402Mhz, 2426Mhz and 2480Mhz. That is so it does not interfere with the 3 wifi channels in the 2.4Ghz band. My question is especially about the 2426Mhz ...
6
votes
0answers
469 views

CISCO ISE Identity Management Group assignment

The Scenario in Brief Three types of devices can exist on our wireless networks: AD joined, corporate owned (Windows PC/Laptop/Surface) Non-AD Joined, corporate owned (iPad/Chromebook and their ...
5
votes
4answers
741 views

How risky is a personal-use-only wireless subnet inside the corporate subnet?

My company's security policy with respect to wireless routers is to not use them at all -- everyone's wired in. Devices for personal use, such as laptops or cell phones, have to use their phone's data ...
5
votes
2answers
1k views

Do I need to re-authenticate every time I switch a access point?

I have multiple Access Points on the same network with a Radius server for authentication. When I switch from one AP to another, do I have to go through the complete re-authentication processes each ...
5
votes
3answers
644 views

Is it possible to build a LAN with just Access Points?

I am just learning the differences between routers and AP. Based on what I have understood, AP just acts like a wireless switch enabling multiple devices to connect to a single router. Since it is ...
5
votes
1answer
6k views

How to disable 802.11b wireless clients on my WLAN?

Most wireless vendors recommend that unless there is a need to support them, 802.11b should be disabled on the network. How should I go about disabling 802.11b on my network?
5
votes
2answers
2k views

Why is RTS/CTS optional for IEEE 802.11?

In wikipedia it is stated: Request to Send (RTS) frame: The RTS and CTS frames provide an optional collision reduction scheme for access points with hidden stations. A station sends a RTS frame as ...
5
votes
2answers
2k views

Is 802.11 bitrate symmetric?

I was wondering when a device spec says that it supports WiFi bitrate of 300 Mbps, is this rate symmetric, i.e. is it the same rate in transmit (device to access point) and in receive (access point to ...
5
votes
3answers
3k views

Is there any relation between MAC addresses of a dual band (2.4 and 5 GHz) router?

I have a use case where I need to determine whether two MAC addresses belong to the same router with dual band connection 2.4 GHz and 5 GHz. When I did some study, I found that the MAC address of ...
5
votes
1answer
517 views

Wireless antenna polarization

I am testing a new 5GHz 6db patch antenna with an 80 degree spread in the horizontal direction and a 30 degree spread in the vertical direction. The antenna has a marking with 'top' on it. My ...
5
votes
3answers
9k views

Can I create a network without a router?

I'm doing a quite simple network setup (hopefully): a file server and a Wi-Fi/AP. The AP which I've got is a biz-grade AP, much more robust, but it is without a built-in router (so no standard DHCP ...
5
votes
3answers
645 views

Will port scanning affect my networks stability?

My company has 2 separated networking systems: wired and wireless. The R&D department is now developing an application that runs on a PC to scan the devices on the wireless network (smartphones ...
5
votes
2answers
375 views

DCF and its relationship with Clear Channel Assesment (CCA) in IEEE802.11

In 802.11, I have been studying different types of CSMA/CA. And I come across the following DCF - Distributed Coordination Function Relies on the ability of computers to physically listen ...
4
votes
3answers
902 views

WiFi planning for warehouse-sized location

I work at a medium-sized retail company, and we'll be moving warehouse sometime early this year. One requirement that we have for the new warehouse is that we need a proper, stable wireless network ...
4
votes
3answers
104 views

Does distance of one user from WiFi AP have negative impact on other connected users?

One of my friends (that knows very well Wireless world) told me following: Consider we have high speed AP. If one user stays out of the range of AP WiFi (lets say 51 meter away) - he will have low ...
4
votes
3answers
224 views

Can access points recognize who passes by?

I was watching a Meraki AP presentation, and one of the features they showed was an analytic tab, which showed the number of devices that passed by, visitors, and connected to the AP, as well as many ...
4
votes
1answer
15k views

TCPDump and listening to wifi traffic of others

This thread is to continue my previous one, where I was talking about the TCPDump command. There is still something I don't get. According to this website (and some others), and according to my ...
4
votes
1answer
15k views

Why would a WiFi extender use the same channel as the primary AP?

I'm trying to set up a simple "wall wart" WiFi extender, a DLink DAP-1520. The setup is straight forward enough, but there seems to be no option for choosing a channel/frequency, so the extender will ...
4
votes
5answers
33k views

Finding out which wifi AP the device used to access the network

Is it possible to find out the MAC Addr of AP the device used to connect the network? I can get the MAC address and IP address of the device(maybe notebook or smartphone), and I have to check the MAC ...
4
votes
2answers
2k views

Decoding wpa-psk traffic with Wireshark

I want to plot how much data each client is using from a wpa-psk protected access point (that I control). For that I intend to monitor all traffic for a couple of days. However I can't decode the TCP ...
4
votes
2answers
468 views

sniff traffic on a private SSID?

Is it possible to sniff for all packets on an encrypted wifi SSID if you know the password? Does the SSID password provide only general isolation for all devices as a group within the SSID, or does ...
4
votes
2answers
215 views

One ethernet plug, one floor ( 30 workstations )

Got a question about ethernet capacity that I'm unsure of. Moving into a new office, and a problem I phase is that there is only 1 ethernet wall plug on the complete floor. So only way would be to ...
4
votes
1answer
1k views

How well does 802.11k actually perform on large-scale networks?

As a student employee I've done some research on 802.11k and I understand that it's intended to help with devices roaming and also helping the client decide on the best (B)SSID to join. In practice ...
4
votes
1answer
744 views

configuring IBSS WLANs

I have searched through wireless books and the web which consistently define what IBSS (ad-hoc, peer-to-peer) is, but have found no examples on how to actually implement one. I'd guess that the steps ...

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