SNR and RSSI on Linksys AP

Does anybody know if SNR and RSSI are available in any of the the Linksys (now part of Cisco)APs SNMP MIB
thanks,
Scott

Similar Messages

SNR and RSSI Values.

HI ,
What is the tha average ,minimum and maximum values of SNR(Signal to noice ratio ) and RSSI (Received Signal Strength Indicator ) in cisco access points   .
And how it is depends on the client connectivity with the Access point.
Thanks & Regards,
Sinjish.K

I am not really sure what you asking here, but My guess is your trying to get a grasp on what SNR and RSSI
values are how they relate to clients, and how they relate to connectivity. If this is the case read on. otherwise well ingore this post..
SNR (Signal-to-Noise Ratio) is a ratio based value that evaluates your signal based on the noise being seen. So let's look at the components of the SNR and they see how to determine it. SNR is comprised of 2 values and is measured as a positive value between 0db and 120db and the closer it is to 120db the better: Signal Value and Noise Value typically these are expressed in decibels (db).
     So we will look at the Signal (Also known as RSSI) first this value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to 0 (zero) the stronger the signal is which means it's better, typically voice networks require a -65db or better signal level while a data network needs -80db or better. Normal range in a network would be -45db to -87db depending on power levels and design; since the Signal is affected by the APs transmit power & antenna aswell as the clients antenna (I'll explain this later.)
     Now to the Noise side of this equation, noise is any signal (interference) that is not WiFi traffic such as cordless phones, microwaves, radar, etc. This value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to -120 (minus 120) is better because that means there is little to no interference. Typical environments range between -90db and -98db.
     So to calculate your SNR value you add the Signal Value to the Noise Value and it generates (or should) a positive number that is expressed in decibels (db); for example lets say your Signal value is -55db and your Noise value is -95db.
                    -55db + -95db = 40db this means you have an SNR of 40, my general rule of thumb is that any SNR above 20 is good.
RSSI (Recieved Signal Strength Indicator) is a more common name for the Signal value; meaning it is the strength that the device is hearing a specific device or signal.RSSI is most common used in bridge links where on client laptops they just call it Signal.
As for your question about the maximum and minimum supported by cisco access points that is hard to answer because the antennas attached to the access points also factor into it. In general the Cisco APs have the following maximum transmit powers: 802.11a/n is 40mw or 14dbm, 802.11b is 100mw or 20dbm, 802.11g is 50mw or 17dbm; although in some cases countries and specific channels can alter these limits.
The last three things I will kind of explain is the EIRP, Free Space Path Loss, and Client side.
EIRP (Effective Isotropic Radiated Power) is the actual amount of signal leaving the antenna and is a value measured in db that is based on 3 things:Transmit Power (db), Cable Loss (db), & Antenna Gain (dbi). To determine EIRP follow this equation: - Cable Loss + Antenna Gain = EIRP. For example we have a Cisco 1242AG access points running at full power with a 6dbi antenna on the 802.11a radio and a 2.5dbi antenna on the 802.11bg radio.
802.11a EIRP = 17db (40mw) - 0db + 6dbi = 23db = 200mw of actual output power
802.11bg EIRP = 20db (100mw) - 0db + 2.5dbi = 22.5db = 150mw (approx) of actual output power
based on the example above in theory if you were to measure it right at the antenna you could get an RSSI of -23 or -22.5 respectively.
Free Space Path Loss is a measure of how much signal power you lose over a given distance typically you lose about 0.020 db per foot in an outdoor or wide open office; doors, walls, glass, and etc. affect this. This is why as you walk away from an AP your signal gets weaker.
All this relates to the client because it determines the signal the client recieves, also keep in mind that when looking at the client you have to account for it's antenna as well. much like the EIRP... So if a client card has a 2 dbi antenna (although they are typically either 0dbi or 2.2dbi) that boosts the incoming signal. as shown here assuming the actual raw RSSI signal being seen is -68db (not the value displayed in the client window).
Actual RSSI + Antenna Gain = Displayed RSSI
-68db + 2db = -66db
I hope all this helps with your question...
Please rate useful posts.
Thanks,
Kayle

What is RSSI , SNR and technical specification value in dbm

Hi,
I am little bit confused about RSSI concept and SNR , Signal strength.
One more thing that , what is technical specification of signal strength and SNR and RSSI for 802.11 a,b,g and n
Because as far as application concern , this values get changed eq. voice , video
I need to get the values according to application.

Hi,
RSSI means Receiver Signal Strength Indicator. It's the strength of the signal as perceived as received by the client. It does not have a precise unit of measurement. On client softwares, it's usually a percentage (that has no real meaning). WLC and APs usually show in dbm.
SNR is Signal/Noise ratio. The noise level is usually at -90dbm let's say. This means that if you have a signal at -90dbm, it's completely lost in the noise, it has a SNR of 0.
A signal at -80dbm has a SNR of 10 in the same conditions, it is barely decodable.
However if the noise level is -95 then a signal of -80 will give a SNR of 15 and will be much more decodable.
Noise is usually between -100 and -90 in normal circumstances.
Dbm is another way of expressing power (rather than milliwatts). The advantage of dbm is that you can add or substract antenna gains very easily since those are in db.
20dbm=100mw
The rule is "if you substract 3dbm, divide the mw by 2" and "if you substract 10dbm, divide the milliwats by 10"
So 17dbm = 50mw
13dbm=25mw
10dbm=10mw
The received signal strength which are usually between -40 and -80dbm are then fractions of fractions of microwatts :-)

I JUST BOUGHT AND INSTALLED A LINKSYS E1200 WIRELESS N ROUTER AT HOME. MY IPHONE CONNECTS WITH A STRONG SIGNAL BUT WHEN I TRY TO USE THE INTERNET IT JUST LOADS FOREVER. HOW CAN I FIX THIS?????!!!!

I JUST BOUGHT AND INSTALLED A LINKSYS E1200 WIRELESS N ROUTER AT HOME. MY IPHONE CONNECTS WITH A STRONG SIGNAL BUT WHEN I TRY TO USE THE INTERNET IT JUST LOADS FOREVER. HOW CAN I FIX THIS?????!!!!

RESET YOUR ROUTER
No. Reset your router.

How to calculate SNR and BER using USRP 2920 with LFTX and LFRX daugher boards.

I have few questions regarding SNR and BER measurement:
I am using two USRP 2920 with daughter boards LFTX and LFRX. One is completely Tx and anothe one is completely Rx. I have following few questions:
Q1: How to control/change Energy per bit (Eb) in LabView? Since for calculating BER you have to increase SNR, and for increasing SNR you have to increase Eb. So can anybody guide me how to increase Eb in LabView?
Q2: Can any body tell me about the noise floor of the above mentioned daughter boards?
Q3: How to set the transmit power of the USRP in LabView? What is the maximum power the above mentioned daughter boards can provide and How should I adjust the "Gain" parameter to transmit the signal with the maximun power?
Thanks
JK

Hi JK,
The energy per bit calculation, as I understand it, is the ratio of the signal power to the bit rate. This means that to increase it, you have to either increase the overall power you are transmitting or decrease the user bit rate. In LabVIEW, you would do this by increasing the gain or by decreasing the IQ rate.
I'm not sure of the noise floor on those boards, but I did have a question. The USRP 2920 is sold in a particular configuration. Did you take it apart and put in the LFTX and LFRX boards? Or is it an Ettus board with these daughterboards attached?
-Jim B
Applications Engineer, National Instruments
CLD, CTD

Connect to Airport Express and Wireless Router (Linksys) at the same time?

I have a laptop that connects to a Linksys wireless G (WRT54G) router. I just got an Airport Express to play iTunes wirelessly over my stereo. Is there a way to connect to both the Linksys router and the Airport at the same time - i.e., connect to the internet as I was over the wireless router AND send music wirelessly from my laptop to my stereo using the Airport Express at the same time?
Dell Laptop Windows XP

Why yes, yes you can.
http://docs.info.apple.com/article.html?artnum=302153
This link shows you how to do it.
Hope this helps.
Toshiba Satelite A-10 Windows XP

Airport Express and WPA2 on Linksys E3000 Router

I'm running MS Windows Vista. I have a Linksys E3000 router and an Airport Express both with updated firmware.
I have segregated my wireless network: My Xbox is on the N-speed band by itself and everything else, including my iPhone 4, is on the g-speed band.
My wireless network works with full Internet access but I can't connect my Airport Express to it. I need help connecting my AE to my existing wireless network so I can stream iTunes music from my PC to the AE.
According to this link: http://www.apple.com/airportexpress/specs.html "When joining an existing wireless network, AirPort Express supports only WPA-Personal. WPA2 requires a Mac computer with an AirPort Extreme Card and Mac OS X v10.3 or later"
So I went to my router settings and set up my g-speed band for "WPA-Personal." But when I do that, my g-speed band ceases to work. I cannot connect my iPhone 4 to it and my iPhone has no trouble connecting when the security is set for "WPA2-Personal".
The Aiport Utility (v 5.5.1) will not detect the AE wirelessly. When I connect the AE via ethernet to the router, I can configure it with Aiport Utility and it will stream iTunes music over the wireline network but then when I disconnect it, I can't detect it wirelessly. I've tried using the setup wizard and the manual setup. I've also reset the AE to it's factory settings and started again with no luck.
I've spent hours trying different settings and I am not sure how to proceed. Please provide any feedback you may have.
Message was edited by: DroidDreamer

Most likely you entered the password a year ago when you first set up the AirPort Express (AX) and you checked the option to store the password in your keychain. If you do that, the Mac will never ask you for the password again.
Open Keychain Access and see if you have an item with the name of your wireless network.

Antennas gain and RSSI

Hi,
we are using 1240 AP and now have changed antenna to 1728 (Gain 5.2dBi) to increase signal strength, but as show Wi-Fi scanner (inSSIDer)
RSSI stays the similar with old and new antennas.
What's wrong? in AP configuration I changed diversity and external antennas gain.
Valentina

Hi, I have captured with inSSIDer and Xirrus: both programs show similar results (pictures are attached). Signal strength was measured from one place and it should be higher with higher gain antenna (distance is about 1 m in these pictures, but similar results with longer distance). Should we some addtional configurations in AP - and where if yes?
(the highest blue line in both pictures with dipole and then 1728)
Valentina

What is the default user and password on linksys wrt54gr

what is the default username and password on my linksys wrt54gr.. i've tried admin and admin and that does'nt work.. any ideas???

If you have setup the routers bridging into the same LAN (i.e. the LAN-LAN connection and not using the internet port on the second router as I have suggested in the link above) and with the wireless settings you have mentioned you should have a wireless roaming network. Make sure you have SSID broadcast enable on both routers.

RSSI & SNR Value

Hello - It is a conceptual question on Wireless SNR & RSSI subject that needs your expertise to shed some lights.
I learned that, for RSSI is the measurement of Power in RF Singal. SNR is the measurement showing how much stronger the wireless signal. I also learned that It’s typically best practice to have the SNR value 20 to 25 dB’s away from the RSSI value. So for example if our RSSI is -61 we would want our SNR value to be around -86, or if our RSSI is -74 we would want the SNR to be -99.
But when i implemented the Cisco Wireless LAN setup, i am observing the below statistics from the Clients.
RSSI : -52
SNR: 41
How the value of SNR is in Positive. Based on my above learning i expected it to be on Negative number and higher than the RSSI ( >-51).
Can you advice where i am wrong?
Thanks in advance
SAIRAM

SNR and RSSI Values.
Unanswered Question
k_sinjish 4 years ago
HI ,
What is the tha average ,minimum and maximum values of SNR(Signal to noice ratio ) and RSSI (Received Signal Strength Indicator ) in cisco access points   .
And how it is depends on the client connectivity with the Access point.
Thanks & Regards,
Sinjish.K
I have this problem too
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Guys - Here is the excellent explanation from Mr.Kyle. Please comment. Thanks
I am not really sure what you asking here, but My guess is your trying to get a grasp on what SNR and RSSI
values are how they relate to clients, and how they relate to connectivity. If this is the case read on. otherwise well ingore this post..
SNR (Signal-to-Noise Ratio) is a ratio based value that evaluates your signal based on the noise being seen. So let's look at the components of the SNR and they see how to determine it. SNR is comprised of 2 values and is measured as a positive value between 0db and 120db and the closer it is to 120db the better: Signal Value and Noise Value typically these are expressed in decibels (db).
So we will look at the Signal (Also known as RSSI) first this value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to 0 (zero) the stronger the signal is which means it's better, typically voice networks require a -65db or better signal level while a data network needs -80db or better. Normal range in a network would be -45db to -87db depending on power levels and design; since the Signal is affected by the APs transmit power & antenna aswell as the clients antenna (I'll explain this later.)
Now to the Noise side of this equation, noise is any signal (interference) that is not WiFi traffic such as cordless phones, microwaves, radar, etc. This value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to -120 (minus 120) is better because that means there is little to no interference. Typical environments range between -90db and -98db.
So to calculate your SNR value you add the Signal Value to the Noise Value and it generates (or should) a positive number that is expressed in decibels (db); for example lets say your Signal value is -55db and your Noise value is -95db.
                    -55db + -95db = 40db this means you have an SNR of 40, my general rule of thumb is that any SNR above 20 is good.
RSSI (Recieved Signal Strength Indicator) is a more common name for the Signal value; meaning it is the strength that the device is hearing a specific device or signal.RSSI is most common used in bridge links where on client laptops they just call it Signal.
As for your question about the maximum and minimum supported by cisco access points that is hard to answer because the antennas attached to the access points also factor into it. In general the Cisco APs have the following maximum transmit powers: 802.11a/n is 40mw or 14dbm, 802.11b is 100mw or 20dbm, 802.11g is 50mw or 17dbm; although in some cases countries and specific channels can alter these limits.
The last three things I will kind of explain is the EIRP, Free Space Path Loss, and Client side.
EIRP (Effective Isotropic Radiated Power) is the actual amount of signal leaving the antenna and is a value measured in db that is based on 3 things:Transmit Power (db), Cable Loss (db), & Antenna Gain (dbi). To determine EIRP follow this equation: - Cable Loss + Antenna Gain = EIRP. For example we have a Cisco 1242AG access points running at full power with a 6dbi antenna on the 802.11a radio and a 2.5dbi antenna on the 802.11bg radio.
802.11a EIRP = 17db (40mw) - 0db + 6dbi = 23db = 200mw of actual output power
802.11bg EIRP = 20db (100mw) - 0db + 2.5dbi = 22.5db = 150mw (approx) of actual output power
based on the example above in theory if you were to measure it right at the antenna you could get an RSSI of -23 or -22.5 respectively.
Free Space Path Loss is a measure of how much signal power you lose over a given distance typically you lose about 0.020 db per foot in an outdoor or wide open office; doors, walls, glass, and etc. affect this. This is why as you walk away from an AP your signal gets weaker.
All this relates to the client because it determines the signal the client recieves, also keep in mind that when looking at the client you have to account for it's antenna as well. much like the EIRP... So if a client card has a 2 dbi antenna (although they are typically either 0dbi or 2.2dbi) that boosts the incoming signal. as shown here assuming the actual raw RSSI signal being seen is -68db (not the value displayed in the client window).
Actual RSSI + Antenna Gain = Displayed RSSI
-68db + 2db = -66db
I hope all this helps with your question...
Please rate useful posts.
Thanks,
Kayle
SAIRAM

Linksys X2000 SNR Margin

I am very glad the Firmware version v2.0.05 has been released to address and rectify the bugs on the previous firmware release.
I am wondering if this update brings any hidden features like checking the SNR and Attenuation statistics of the DSL line?
Sometimes its vital to check and monitor those numbers so it would be great if there is a way round to it or if a future firmware release will add the possiblity to check the SNR and Attentuation.
Cheers!

I can acces my SNR margin now, after installed Router Stats, Thx
Spoiler (Highlight to read)
RouterStatsVendor:LINKSYS
ModelName:X2000
Firmware Version:v2.0.05 build 002 Feb 21,2013
Boot Version:v0.07
CodePattern:2000
Country:EU
Language:EN
-----2.4G Wireless Settings-----
RF Status:enabled
RF Firmware Version:5.60.120.1.cpe4.06L02.2
RF Domain:channel (1-13)
RF Channel:0
RF SSID:Kos
-----Dynamic Information-----
RF Guest Mac Address:52:fc:11:dc:83:cf
RF2G Mac Address:98:FC:11C:83:CE
LAN Mac Address:98:fc:11:dc:83:cf
WAN Mac Address:98:fc:11:dc:83:cd
Hardware Version:01
Device Serial No:01310J0A100211
GUID:J1310A100211
-----DSL Information-----
DSL Driver Version:A2pD035a.d23f
DSL VPI/VCI:0/35
DSL Status:Up
DSL Mode:ADSL_2plus
DSL UpStream Rate (Kbps):604
DSL DownStream Rate (Kbps):2454
Down Up
DSL Noise Margin (0.1 dB): 499 295
DSL Attenuation (0.1 dB): 25 32
DSL Transmit Power (0.1 dB): 0 126
-----SysInfo Log-----
RouterStatsVendor:LINKSYS
ModelName:X2000
Firmware Version:v2.0.05 build 002 Feb 21,2013
Boot Version:v0.07
CodePattern:2000
Country:EU
Language:EN
-----2.4G Wireless Settings-----
RF Status:enabled
RF Firmware Version:5.60.120.1.cpe4.06L02.2
RF Domain:channel (1-13)
RF Channel:0
RF SSID:Kos
-----Dynamic Information-----
RF Guest Mac Address:52:fc:11:dc:83:cf
RF2G Mac Address:98:FC:11C:83:CE
LAN Mac Address:98:fc:11:dc:83:cf
WAN Mac Address:98:fc:11:dc:83:cd
Hardware Version:01
Device Serial No:01310J0A100211
GUID:J1310A100211
-----DSL Information-----
DSL Driver Version:A2pD035a.d23f
DSL VPI/VCI:0/35
DSL Status:Up
DSL Mode:ADSL_2plus
DSL UpStream Rate (Kbps):604
DSL DownStream Rate (Kbps):2454
Down Up
DSL Noise Margin (0.1 dB): 499 295
DSL Attenuation (0.1 dB): 25 32
DSL Transmit Power (0.1 dB): 0 126
-----SysInfo Log-----

Wireless Communication problem between HP Photosmart C309g and Linksys E2500 router

Hello,
I used C309g connected to DLink Dl-624 router (wireless connection) and everything was working correctly. Now I changed the router to Linksys E2500 (dual band router) and I've got strange problem I cannot fix.
The printer connects to router, obtaint IP address and network report does not indicates any problem. Also HP Print & Scan Doctor does not report any problem.
But when I try to print from my laptop, the pint start and is quickly broken, and I've got the message that printer is diconnected. The printer stops. When I leave it for a coupl of minutes, the printing starts and after few lines stops again with the same message on the laptop.
When I return to DLink router, everything works correctly.
I tried with 4 different laptops, with different operating systems, and i've gor the same issue. But the laptops communicates well, the network does not break..
I enforced router to use IP reserved number for the printer, used the same IP range and number for my network and printer on Linksys and DLink, does not help. I've turn off firewall on the router - does not help. I've change the channel range for 2.4 GHz network to 20MHz only - does not help.
What would be the problem with it? Is there something related to dual-band? Any idea?

Well, I did not install the printer drivers from cd, I did it from the Hp webpage. Looking for the potential problems I reinstall the drivers and it did not helped. I also turn off the firewall router application and it also did not help.
I suspect I have the printer firmware up to date e.g my version is WHM1FN0931BR.
I've made some test with router settings: switch from automatic WPS configuration to manual and tried network mode as wireless b only (default was mixed). This makes the communication between router and printer continuous (no breaks), I could normally scan documents directly to network drive, but could not print at all: the printing option on my laptop pops up, and looks like document was sent to nowhere.. printer did not start to print at all. But other network devices starts to experience connection breaks and performance issues. When I returned to mixed mode, the communication between network devices returns to normal operation, but not with the printer - where I experiences original problems.
My network is quite complex - 4 laptops and 2 TV sets communicates (wireless or LAN 100mbit cable ) via cental router with NAS server (with DLNA) and internet (DSL cable modem). Router also works as DHCP server, where any server type devises (e.g my printer) has reserved IP addresses (based on MAC number). No matter if I try to print from wireless or via LAN cable laptop, no matter what OS is on laptop. I have even tried to connect the printer via LAN (forcing DHCP to give the LAN pronter the same IP as was previously for wireless ), and stil the same: communication is broked and the print starts and suddenly stops.., then starts angain after few minutes - and stops (the same problem as wireless). So I do not understand what the hell is going on. Rest of my network works perfect .. except this printer.. Any other idea, what coul be the issue?

Linksys e900 and comcast xfinity internet speed

I just recently purchased comcast internet today and self installation kit that came with the modem and all..... got it all set up no problems activated did speedtest directly from cable modem to laptop computer wired and was getting 10mbps down and 3mbps up well went out and bought a linksys e900 wireless router.... connected it no problems... however my laptop wirelessly and phones connected to the router with speedtest is only getting 300kbps down average!!! but the upload is still 3mbps.... is there something im doing wrong? any help is appreciated!

The above is not an entirely accurate statement. What I can says is... 'it depends'. Depends on your brand of router and brand of WiFi adapter. I now use a Netgear WNDR3400v2 router with a Linksys AE1000 USB adapter on my Toshiba Satellite laptop. With WMM disabled in the router, I can connect at 300 Mbps and transfer wirelessly to my downstairs computer at a max rate of 82.5Mbps. Why only 82.5Mbps? Well the router and computer downstairs only have 100Mbps LAN connections. With WMM enabled my connection link is still 300Mbps but my speed is reduced, but not by much. Go figure. Comcast speed is perfect at about 24Mbps with WMM disabled, only 12-14Mbps with WMM enabled. And yes it is an N connection all the time.
Using the internal WiFi adapter, Intel 5100 b/g/n I can only get a connection of 9-14Mpbs. That's right only 14Mbps with all the latest drivers installed. Comcast speed is only about 7Mbps using the internal WlFi adapter. WMM enabled or disabled, no difference.
So, it depends. I suggest trying a cheap external USB adapter like the above. Only $14 on eBay.

AP1231G And Linksys WUSB54G

HI
I buy a new AP1231G as our offce wireless hub and buy some Linksys WUSB54G (USB wireless adaptor of our Notebooks)
When I configurate the SSID, Encryption level. So I try to connect to wireless hub with the notesbook.
I found some problems
1. Although the the connection is established (according to AP1231 console information) the notesbook can't been assign the IP, in the others word, the notebook can't find the DHCP server. IP address of notebook is 169.xxx.xxx.xxx ( I have double checked the setting of WEP, SSID) Any idea to solve it?
2. From the Console of AP1231G. it recongine the linksys adaptor as repeator. not a Client. Is it correct?
Thx for your help

I have seen the same with Intramec scanner (PDA Client)
Tray to switch off the Aironet extension
(in cli type "no dot11 extension aironet")

Cisco Network Assistant, and Linksys Switches?

Hi all,
Given that Cisco owns Linksys, that CNA seems aimed at the small/medium business market, and that many of those businesses (like me) probably mix and match Linksys managed switches (like the SRW series) as leaf switches hanging off other higher end Cisco network gear, It seems to me that making CNA ccapable of discovering and managing those Linksys switches would make a lot of sense.
Is there any hope or plan for this in the future?
-Kyle

I would like to see this as well. I have nine Linksys SRW2024 units and it is a pain to go into each one seperately. I am used to the Cisco Network Assistant and it would greatly help if they could talk to LinkSys smart switches. Please!
-Milt Hull

SNR and RSSI on Linksys AP

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