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taloot
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eXtended Range

Sun Apr 23, 2006 4:34 am

is mikrotik support this future??
i read some artical about it that it help very much in outdoor envirment
anyone have info lets share
 
taloot
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Mon Apr 24, 2006 3:58 am

no answers??
 
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stephenpatrick
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Mon Apr 24, 2006 10:56 am

It's been asked for ... "XR" feature on Atheros cards. No sign yet ...
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rtr989
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Mon Apr 24, 2006 5:57 pm

Is Mikrotik plans to support "XR"?
 
uldis
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Tue Apr 25, 2006 2:36 pm

Currently there are no plans to add support for XR.
 
rtr989
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Tue Apr 25, 2006 2:53 pm

Currently there are no plans to add support for XR.
Why not? I think it`s very important feature... Is it to hard?
 
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normis
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Tue Apr 25, 2006 2:54 pm

why do you think that it is imortant? in my personal opinion, nstreme is better in doing the same thing
 
rtr989
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Tue Apr 25, 2006 3:45 pm

why do you think that it is imortant? in my personal opinion, nstreme is better in doing the same thing
The nstream and XR is absolutely different things..

The nstreme protocol is MikroTik proprietary (i.e., incompatible with other vendors) wireless protocol created to improve point-to-point and point-to-multipoint wireless links.

But XR (eXtended Range Technology) is a new baseband architecture that dramatically stretches the performance of a WLAN by enabling long-range connections. The architecture delivers receive sensitivities of up to –105dBm, over 20 dB better than the 802.11 specification. So the wireless client (i.e. notebook with build in atheros wireless card), can work without direct visibility, in some conditions speed of a link down to 0.25Mbps, but link work fine.. I test it in my own network, it`s work perfectly!..
XR is not for a fast link, it`s for a long link with bad conditions!
 
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normis
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Tue Apr 25, 2006 4:02 pm

have you tested that it actually does this? or is this a marketing trick?
 
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stephenpatrick
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Tue Apr 25, 2006 4:13 pm

Just my $0.02 here -

AFAIK XR allows the atheros radio to work at lower signal strengths than the 802.11 standard normally allows - hence the range improvements.
Atheros have an explanation on their site.

That might help some setups (especially indoor WLAN or hotspot) but will probably upset Nstreme, which in our tests generally doesn't like "marginal" signals very much, due to the re-processing/packing of packets into frames - i.e. a lost/errored frame can lose more than one packet.
Comments from others welcome. Personally, I'd like to see the feature added, we can all turn it on/off as the specific scenario requires.

Regards
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rtr989
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Tue Apr 25, 2006 6:58 pm

have you tested that it actually does this? or is this a marketing trick?
i test it on D-Link-2100 and 7100 with d-link G650(pcmci) and G520(PCI), it`s work there where usual 802.11b/g do not work. Now i use XR on my AP`s based on AP39 platform.. but i can`t use it with Mikrotik :( It is very a pity that the Mikrotik does not support this standard..
 
eflanery
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Tue Apr 25, 2006 10:24 pm

XR is hardly a standard, it's an Atheros-propritary extension.

It's nothing more than a modulation change that makes the symbols "easier" to decode, since a significantly smaller amount of data is being encoded. By thrashing the spectrum, it makes it more likely that super-low-speed super-low-quality connections will work, at the expense of everything else.

It could be useful under certain conditions, but I can't imagine using it much. The performance hit would be huge, and the "spectrum-time" efficiency is horrific (worse than the old 802.11 2Mbit hoppers, even; right up there with most SCADA systems).

Links would be easier to make with XR, but everyone (the XR-user included) would be better off just getting better antennas.

It's already nasty enough out there, we don't need to turn things into even more of a "race to the bottom".

--Eric
 
rtr989
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Tue Apr 25, 2006 10:30 pm

Any way, if you use notebook, you can`t use better antennas... or if you have a tree on a linkway, regular 802.11b/g does not work or work very bad, and in this situations XR is great feature..
 
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Wed Apr 26, 2006 12:28 am

Indeed, it would be beneficial in certain applications, and I would not mind if MT added support.

But, I don't think I would use it much (if at all). And I would encourage others to use it only as a last resort, I'm not eager to see 20Mhz of spectrum eaten up by a 150Kbps network.

--Eric
 
rtr989
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Wed Apr 26, 2006 8:58 am

may be you right, but i am an Wireless ISP, and i realy need this feature, that`s why i still use AP39, but would prefer a Mikrotik if it supported XR.
 
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Hammy
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Thu Apr 27, 2006 6:14 pm

Just my $0.02 here -

AFAIK XR allows the atheros radio to work at lower signal strengths than the 802.11 standard normally allows - hence the range improvements.
Atheros have an explanation on their site.

That might help some setups (especially indoor WLAN or hotspot) but will probably upset Nstreme, which in our tests generally doesn't like "marginal" signals very much, due to the re-processing/packing of packets into frames - i.e. a lost/errored frame can lose more than one packet.
Comments from others welcome. Personally, I'd like to see the feature added, we can all turn it on/off as the specific scenario requires.

Regards
If N-Streme doesn't like low signal links, wouldn't XR assist by being able to better process a frame when at a low receive signal?
 
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stephenpatrick
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Fri Apr 28, 2006 1:12 pm

Not AFAIK - to "process" the frame at lower signal level means let more through the receiver with errors, as the signal is closer to the noise (or interference) floor.
Not much of a problem for regular WiFi with TCP/IP connections, as packets are resent: but a big problem for Nstreme, where lost packets affects traffic a lot more.
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rtr989
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Sun May 07, 2006 5:01 pm

*************************************************
00:15:e9:42:51:7d, State: associated, AID: 2(XR)
Authentication Type: Open System
WLAN Mode: 2.4GHz 54Mbps (802.11g), nonERP present: NO, nonERP protected: NO
Encryption: OFF Ciphers: NONE(unicast), NONE(multicast), NONE
Compression: OFF
Power Save Mode: OFF
Rx Data Rate: 5.5, Local RSSI level: -108 dBm, Remote RSSI level: -106 dBm
MSDU Data Mcast Mgmt Ctrl Errors
Rx 235 4117 223 245 0 0
Tx 301 43 0 249 0 42


*************************************************


This link is about 500meteres in the tree area..
Works very fine..
Used a Atheros AP39(D-Link 2100AP) and Atheros AR5213(D-Link G520) card in XR mode..
If i turn off XR mode, link is down..
 
wsgtrsys
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Re: eXtended Range

Sun Mar 02, 2008 1:12 pm

http://madwifi.org/wiki/ChipsetFeatures/XrMode
Introduction ¶
This document applies to the madwifi-ng source code. Conclusion provided here were based on the analysis of the source code revision r1531.

Theory of operation ¶
XR means "eXtended Range". This is a mode which extends the operational range of an AP by using lower and non standards rates : 0.25 Mb, 0.5 Mb, 1 Mb, 2 Mb, 3 Mb. It probably use the OFDM modulation as in 802.11g. Since it's a proprietary Atheros extension, several points needs to be taken care of :

XR mode only works between two devices having such capabilities. To know the capabilities of an AP, a special Information Element (IE XR) is contained in its beacon.
An AP might handle clients in XR mode and clients in non-XR mode. Since non-XR mode clients won't receive XR mode packet, we might have a hidden node problem. To avoid this situation, the XR mode seems to be a polled mode. The polling is probably initiated by the AP which issues a CTS request to forbid other station from transmitting. During this period, XR packets are sent between XR STA and XR AP.
Normally, AP beacons are broadcasted at 1 Mb rate since it's the lowest common denominator across all clients. When operating in XR mode, this is no longer the case. So, it might be needed for the AP to broadcast beacons at the 0.25 Mb rate as well.
Functional description ¶
To enable XR mode : iwpriv wlan0 xr 1
To disable XR mode : iwpriv wlan0 xr 0
Implementation description ¶
By reading the madwifi source code, it seems that the XR mode is implemented using a special VAP. Currently, madwifi is only supporting XR mode when operating as a STATION and not as an AP.

wish mikrotik can add support for XR!
 
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jordantrx
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Re: eXtended Range

Sun Mar 02, 2008 4:10 pm

http://madwifi.org/wiki/ChipsetFeatures/XrMode
Introduction ¶
This document applies to the madwifi-ng source code. Conclusion provided here were based on the analysis of the source code revision r1531.

Theory of operation ¶
XR means "eXtended Range". This is a mode which extends the operational range of an AP by using lower and non standards rates : 0.25 Mb, 0.5 Mb, 1 Mb, 2 Mb, 3 Mb. It probably use the OFDM modulation as in 802.11g. Since it's a proprietary Atheros extension, several points needs to be taken care of :

XR mode only works between two devices having such capabilities. To know the capabilities of an AP, a special Information Element (IE XR) is contained in its beacon.
An AP might handle clients in XR mode and clients in non-XR mode. Since non-XR mode clients won't receive XR mode packet, we might have a hidden node problem. To avoid this situation, the XR mode seems to be a polled mode. The polling is probably initiated by the AP which issues a CTS request to forbid other station from transmitting. During this period, XR packets are sent between XR STA and XR AP.
Normally, AP beacons are broadcasted at 1 Mb rate since it's the lowest common denominator across all clients. When operating in XR mode, this is no longer the case. So, it might be needed for the AP to broadcast beacons at the 0.25 Mb rate as well.
Functional description ¶
To enable XR mode : iwpriv wlan0 xr 1
To disable XR mode : iwpriv wlan0 xr 0
Implementation description ¶
By reading the madwifi source code, it seems that the XR mode is implemented using a special VAP. Currently, madwifi is only supporting XR mode when operating as a STATION and not as an AP.

wish mikrotik can add support for XR!
I Beleive they do now..... Can we Not ad an XR2 to our routerbaords, and it works?? I am using sr2 but plan on using Xr2.. And i have heard many times on this fourm of people using xr2 so im guessing they have chosen to support it. and if so thank YOU! -Jordna
~Agricultural WISP "ZONE"~ Beware of oncoming cattle and dont hit the farmer!!! I need to ask him about using his silo for an AP first"~

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0ldman
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Re: eXtended Range

Sun Mar 02, 2008 5:15 pm

extended range is an Atheros modulation scheme that allows for very weak signal. Xtended Range 2, XR2, is a high powered mini PCI card.

I'd still love to have Atheros XR support. I've used it before on other devices and it lives up to the hype. Not that I'm planning on having links that bad, but as has been mentioned several times on the forum, when something goes wrong, noise, diversity chip blows, etc, its better to have slow internet than no internet. It gives a little time to figure out what happened.
 
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jordantrx
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Re: eXtended Range

Sun Mar 02, 2008 5:47 pm

extended range is an Atheros modulation scheme that allows for very weak signal. Xtended Range 2, XR2, is a high powered mini PCI card.

I'd still love to have Atheros XR support. I've used it before on other devices and it lives up to the hype. Not that I'm planning on having links that bad, but as has been mentioned several times on the forum, when something goes wrong, noise, diversity chip blows, etc, its better to have slow internet than no internet. It gives a little time to figure out what happened.
Yes your right I was getting Xtream range , mixed up with eXtended range.... Does anybody have a link to this eXtended range, so i could get more information about it? Or i will google. Thanks -Jordan
~Agricultural WISP "ZONE"~ Beware of oncoming cattle and dont hit the farmer!!! I need to ask him about using his silo for an AP first"~

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0ldman
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Re: eXtended Range

Mon Mar 03, 2008 6:31 am

You can get decent info at Atheros home page, don't have the addy off hand. I'm still on dial up until I get this rolled out, so google is more your friend than mine at this point.

The Atheros PR sounds like general PR fluff, but it actually works. I've used with signals as low as -106dB. Usually a 256K or so connection, maybe less, but slow is better than no.
 
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jordantrx
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Re: eXtended Range

Mon Mar 03, 2008 4:47 pm

You can get decent info at Atheros home page, don't have the addy off hand. I'm still on dial up until I get this rolled out, so google is more your friend than mine at this point.

The Atheros PR sounds like general PR fluff, but it actually works. I've used with signals as low as -106dB. Usually a 256K or so connection, maybe less, but slow is better than no.
I agree, I would much rather have a low connection than no connection at all, It has my vote to be supported... I will look up more on it later... ONe of my question would be is if this card is in the AP, does the same card have to be in the client. Like the 900mhz cards if you have an XR9 in the AP it has to be in the client aswell...


Fyi Oldman, i am on cellular internet one jump up from dialup (144Kbps),, im providing high speed to customers, and i dont even have high speed yet :-P . But my coverage is spreading i tell you! MY way! :-P -Jordan
~Agricultural WISP "ZONE"~ Beware of oncoming cattle and dont hit the farmer!!! I need to ask him about using his silo for an AP first"~

*Automated Billing Installer* http://wiki.mikrotik.com/wiki/AutomatedBilling Built by Krige ;-)
 
0ldman
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Re: eXtended Range

Mon Mar 03, 2008 5:26 pm

It has to be an Atheros AP and client. An XR2 should work just fine with a CM9, R52, R52H, SR2, etc...

I haven't tried it with the XR9 yet. I've only got one AP at home that supports extended range and no client, aside from my laptop, and I'm kind of scared of putting a 1 amp mini PCI card in my laptop, if it will physically fit in the slot, its a bit tall.

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