RE: Wireless bridge
Hi NANOG, I promised to post an update down the line on what happened with my wireless situation. Here it is. I purchased 2x Ubiquity Bullet2's (2.4 GHz) and utilized our existing antennas. It has been working extremely well, pushing a stable 54 Mbps over the link without issue. Signal strength is consistently -40 dBm +/- 2 dBm, from about -80 dBm before! Total cost included 2x Bullets, 2x PoE adaptors, and approx 40 ft of STP cat5: $120. I have yet to see what happens in a big thunderstorm, but I extrapolate that they will be able to handle the EMP without going haywire like before. They have worked very well through conditions that our last setup would not. Thanks again for the input everyone! Peter -Original Message- From: Peter Boone [mailto:na...@aquillar.com] Sent: June-18-09 9:46 PM To: nanog@nanog.org Subject: RE: Wireless bridge OK, from reading all the excellent feedback I've got on and off list I've attempted to compile a "quick" summary of findings/ideas/products so far. - RouterBoard is no good for this type of application. - Get a unit with radio/antenna integrated, PoE from inside the building (outdoor rated cat5, shielded I assume), lightning suppression for the PoE (properly grounded), and ensure the mast is properly grounded. - Get off the 2.4 GHz range. Move up to 5. As for licensed vs. unlicensed, I'm getting mixed input. I'm fairly certain that if the price is right and the frequency is 5GHz+, it won't be a factor. Also, I'll be very glad to separate the bridge from the client access points so that allows for more options. Every solution at this range can easily do 20+ Mbps so throughput is no longer a factor. - Products that support ARQ are highly recommended. - I'm hearing the same products mentioned over and over: - Motorola - Ubiquiti - Aironet (Cisco) - Aruba A number of individuals recommended products from other brands at low cost that meet these mentioned requirements too. I'm not going to bother with a spectrum analyzer. In the current implementation we tried channels 1, 6 and 11 for a few days at a time and found 1 to be the most reliable. Done. At this point an analyzer will tell me what I already suspect: there's a problem. I've researched the Fresnel zones and calculated out a few things with rough numbers and worst case. For one, the Fresnel zone is disrupted most if the obstruction is closer to the endpoints (e.g. antennas). In this case, this is fine as the antenna are mounted at the outermost corner of the buildings as close as possible to the other buildings, approximately 3 floors in the air. Other buildings become a factor near the middle. Based on channel 1's wavelength of 0.12438 m, and assuming 1 km apart (for simplicity sake. It's actually less), the Fresnel zone is largest in the center at approx 5.6 m radius. That could definitely be obstructed by rooftops, I'll have to take another look though. This radius cuts in half when the frequency is doubled, thus more evidence in favour of the 5 GHz+ range. Cool. Or we could just go with a good line of sight optical solution but they look too expensive, and this area can have very unforgiving fog/wind to disrupt things further. What if we tilt each existing antenna up towards the sky 10-20 degrees? Please correct me if I'm wrong. The current antennas are plates. I'm pretty sure they are polarized. I used to have a product sheet on these but a Google search doesn't turn up any useful results anymore (SmartAnt PCW24-03014-BFL). The way they are mounted to the poles might make it difficult to try rotating them 90 degrees, but worth another look. The coax between the AP and antennas are no longer than 30 feet. I've often wondered if a Pringle or Coffee Cantenna would work better than these! For right now I'll have the coax line and ends inspected for damage/softspots, check the grounding, and cover/re-cover the ends in large amounts of rubber/electric tape. I think we might try the Ubiquiti Bullet2 for approx $100 per side (PoE supply/lightning suppression, wiring included) and see what happens! If that doesn't work, no major loss and we'll move up to something more serious (the PoE and wiring will already be ready to go). I will have to look into pricing on some of these suggestions and figure out if we should even bother getting a Bullet but instead go straight to a better all-in-one solution. Thank you guys very much for the tips. Feel free to keep them coming! Peter
Re: Wireless bridge
Peter Boone wrote: I purchased 2x Ubiquity Bullet2's (2.4 GHz) and utilized our existing antennas. It has been working extremely well, pushing a stable 54 Mbps over the link without issue. Signal strength is consistently -40 dBm +/- 2 dBm, from about -80 dBm before! Total cost included 2x Bullets, 2x PoE adaptors, and approx 40 ft of STP cat5: $120. I have yet to see what happens in a big thunderstorm, but I extrapolate that they will be able to handle the EMP without going haywire like before. They have worked very well through conditions that our last setup would not. Thanks again for the input everyone! Peter More an FYI as I'm not overly familiar with Ubiquity's, but I believe -40dBm is kind of a hot signal which means they are screaming at each other, are you seeing any physical errors, specifically CRC's?. Won't necessarily affect overall throughput, but -60dBm is the sweet spot...too much of a signal is just as bad as not enough...sort of like that Sienfield episode of the the close talker :). Bret
Re: Wireless bridge
No, you are not pushing a stable '54mbps over the link without issue'. More likely, if you cared to look, you are getting somewhere around 30-35mbps, HALF DUPLEX. The '54mbps' advertised on the shiny sales brochure, is a signaling rate and not a measure of thruput. Mike- Bret Clark wrote: Peter Boone wrote: I purchased 2x Ubiquity Bullet2's (2.4 GHz) and utilized our existing antennas. It has been working extremely well, pushing a stable 54 Mbps over the link without issue. Signal strength is consistently -40 dBm +/- 2 dBm, from about -80 dBm before! Total cost included 2x Bullets, 2x PoE adaptors, and approx 40 ft of STP cat5: $120. I have yet to see what happens in a big thunderstorm, but I extrapolate that they will be able to handle the EMP without going haywire like before. They have worked very well through conditions that our last setup would not. Thanks again for the input everyone! Peter More an FYI as I'm not overly familiar with Ubiquity's, but I believe -40dBm is kind of a hot signal which means they are screaming at each other, are you seeing any physical errors, specifically CRC's?. Won't necessarily affect overall throughput, but -60dBm is the sweet spot...too much of a signal is just as bad as not enough...sort of like that Sienfield episode of the the close talker :). Bret
RE: Wireless bridge
Hi Mike, Sorry for the misunderstanding, allow me to paraphrase: the link does not drop, actual throughput is now faster than our internet connection, and transfers have not been interrupted, so we are happy. As I mentioned, our previous setup could only work reliably when locked at 6 Mbps, and even then there were interruptions and mysterious downtime, so a 54 Mbps theoretical max rate has been a godsend. Also, there were no "shiny sales brochures" involved in the decision, the Bullet2's were the most cost-effective solution to get the job done, and at minimal loss if the odd problems were not actually solved (see the archive of this thread from June 2009 for details). Bret, You are correct, the Bullets are on max output power right now so they are loud, and I just found that Ubiquiti recommends aiming for -50 to -70 dBm "for stable links". I always looked at the hot signal issue like a bad quality speaker turned up too loud; where in this case the speaker is the wireless radio. Since there have been no wireless errors and (aside from a small number of expected Invalid Network ID errors) and the dBm is high I figure the signal is loud and clear on each end, but I'll be sure to tweak the power output. There have actually been more error packets on the wire than in the air (0.01% of LAN packets). Regards, Peter -Original Message- From: Mike [mailto:mike-na...@tiedyenetworks.com] Sent: April-05-10 4:02 PM To: Bret Clark Cc: nanog@nanog.org Subject: Re: Wireless bridge No, you are not pushing a stable '54mbps over the link without issue'. More likely, if you cared to look, you are getting somewhere around 30-35mbps, HALF DUPLEX. The '54mbps' advertised on the shiny sales brochure, is a signaling rate and not a measure of thruput. Mike- Bret Clark wrote: >Peter Boone wrote: > > > I purchased 2x Ubiquity Bullet2's (2.4 GHz) and utilized our existing > antennas. It has been working extremely well, pushing a stable 54 Mbps over > the link without issue. Signal strength is consistently -40 dBm +/- 2 dBm, > from about -80 dBm before! Total cost included 2x Bullets, 2x PoE adaptors, > and approx 40 ft of STP cat5: $120. I have yet to see what happens in a big > thunderstorm, but I extrapolate that they will be able to handle the EMP > without going haywire like before. They have worked very well through > conditions that our last setup would not. > > Thanks again for the input everyone! > > Peter > >More an FYI as I'm not overly familiar with Ubiquity's, but I believe >-40dBm is kind of a hot signal which means they are screaming at each >other, are you seeing any physical errors, specifically CRC's?. Won't >necessarily affect overall throughput, but -60dBm is the sweet >spot...too much of a signal is just as bad as not enough...sort of like >that Sienfield episode of the the close talker :). >Bret >
Re: Wireless bridge
On Thu, Jun 18, 2009 at 09:05:56AM -0400, Peter Boone wrote: > Hi NANOG, > > I'm looking for some equipment recommendations for a wireless bridge between > two locations approximately 500-800 meters apart. The current setup for this > company has been extremely unstable and slow. I don't have a lot of > experience in this area so I was hoping someone could give me a few > pointers. I've had good luck with Cisco Aironet gear running in repeater mode. I've done the cheap linksys thing as well and it just did not work as well as using some equipment that was better designed. I have actually found the non-IOS software on the aironet 350/340 to be more usable than the IOS software. You need to have your network be consistent. You also have the obvious interference challenges with any unlicensed deployment. - Jared some of the equipment i've used: http://cgi.ebay.com/5-Cisco-Aironet-350-WAPs-AP352E2R-A-K9_W0QQitemZ200351697798QQcmdZViewItemQQptZCOMP_EN_Routers?hash=item2ea5e44b86&_trksid=p3286.c0.m14&_trkparms=65%3A1|66%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50 http://cgi.ebay.com/Cisco-AIR-AP1121G-A-K9-Aironet-1100-1121-Access-Point_W0QQitemZ190313803887QQcmdZViewItemQQptZCOMP_EN_Routers?hash=item2c4f96306f&_trksid=p3286.c0.m14&_trkparms=65%3A1|66%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50 -- Jared Mauch | pgp key available via finger from ja...@puck.nether.net clue++; | http://puck.nether.net/~jared/ My statements are only mine.
Re: Wireless bridge
We've used aironet since before cisco owned it. We just recently went fiber for most of the district, but still running one aironet connection a good distance apart. On Thu, Jun 18, 2009 at 9:18 AM, Jared Mauch wrote: > On Thu, Jun 18, 2009 at 09:05:56AM -0400, Peter Boone wrote: > > Hi NANOG, > > > > I'm looking for some equipment recommendations for a wireless bridge > between > > two locations approximately 500-800 meters apart. The current setup for > this > > company has been extremely unstable and slow. I don't have a lot of > > experience in this area so I was hoping someone could give me a few > > pointers. > > I've had good luck with Cisco Aironet gear running in repeater > mode. > >I've done the cheap linksys thing as well and it just did not work > as well as using some equipment that was better designed. > >I have actually found the non-IOS software on the aironet 350/340 to > be more usable than the IOS software. You need to have your network be > consistent. > >You also have the obvious interference challenges with any > unlicensed > deployment. > >- Jared > > some of the equipment i've used: > > > http://cgi.ebay.com/5-Cisco-Aironet-350-WAPs-AP352E2R-A-K9_W0QQitemZ200351697798QQcmdZViewItemQQptZCOMP_EN_Routers?hash=item2ea5e44b86&_trksid=p3286.c0.m14&_trkparms=65%3A1|66%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50 > > > http://cgi.ebay.com/Cisco-AIR-AP1121G-A-K9-Aironet-1100-1121-Access-Point_W0QQitemZ190313803887QQcmdZViewItemQQptZCOMP_EN_Routers?hash=item2c4f96306f&_trksid=p3286.c0.m14&_trkparms=65%3A1|66%3A2|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50 > > > -- > Jared Mauch | pgp key available via finger from ja...@puck.nether.net > clue++; | http://puck.nether.net/~jared/ My statements are only > mine. > >
Re: Wireless bridge
On Thu, Jun 18, 2009 at 09:05:56AM -0400, Peter Boone wrote: > I'm looking for some equipment recommendations for a wireless bridge between > two locations approximately 500-800 meters apart. The current setup for this > company has been extremely unstable and slow. I don't have a lot of > experience in this area so I was hoping someone could give me a few > pointers. We use Nortel 7230 wireless bridges and are *very* happy with them. They run at 5.8 GHz, 20 Mbps full duplex (really 18 Mbps data rate), do transparent bridging, and pass VLAN tagged frames just fine. For one particular link, we continually push the full 18 Mbps and they work fine. They are PoE powered via a power brick in the network closets, with a single Cat5 cable up to the outdoor unit which has the antenna integrated. We've had very few failures over the years--mainly a few infancy failures shortly after installation. We have about 40 units (20 links), all less than 1 km apart, most of them a few hundred meters across city streets. These are the third generation of wireless bridge products we have used, and they far outperform the older ones, especially from a reliability and maintenance perspective. We will be looking to upgrade these over the next few years to get more bandwidth in some locations, and I'm not overly optimistic about finding something that matches these from a reliability and ease-of-use perspective--I would appreciate it if you share a summary of any results you find.
Re: Wireless bridge
Peter Boone wrote: Hi NANOG, I'm looking for some equipment recommendations for a wireless bridge between two locations approximately 500-800 meters apart. The current setup for this company has been extremely unstable and slow. I don't have a lot of experience in this area so I was hoping someone could give me a few pointers. I have had good luck with Airaya. May be a bit pricy for your application but they are solid. The one I am on right now has to be at least five years old. http://airaya.com Whatever you do, move out of 2.4Ghz. That's probably 50% of your problems right there.
Re: Wireless bridge
Cisco Aironet www.cisco.com Alvarion www.alvarion.com Aruba www.arubanetworks.com bluesocket www.bluesocket.com I've used all but bluesocket and they all worked pretty well. bluesocket gets good reviews. These are just a few. There are lots of them. Try to use one as and access point and use one as a client. Working in repeater mode will cut your bandwidth in half. --Curtis Peter Boone wrote: Hi NANOG, I'm looking for some equipment recommendations for a wireless bridge between two locations approximately 500-800 meters apart. The current setup for this company has been extremely unstable and slow. I don't have a lot of experience in this area so I was hoping someone could give me a few pointers. Currently, both locations are using Linksys WRT54GL's flashed with DD-WRT firmware (Yes, 802.11g. All extra bells and whistles are disabled in the firmware. They were set up for WDS so other wireless clients could connect to the same access point, with varying degrees of success. Not very important). They are connected to SmartAnt 2300-2500 MHz 14 dBi directional antenna mounted on the roof (extended pretty high for perfect line of sight). I'm not sure when they got these antenna exactly but I'm told it was when WiFi was very new. The network is very small so both locations share the same subnet (192.168.1.0/24). They have gone through numerous Linksys access points over the years. The wireless settings are tweaked as best as possible, and we have found the connection to be most stable when the TX is limited to 6-9 Mbps. We have explored other options as well. An internet connection at each location + VPN is out due to very slow upstream speeds (the buildings are in an industrial area, ADSL is the only option.) The max they offer on regular business accounts is 800 kbps up. T1 lines are even slower and even more expensive. They won't offer us any other solutions such as fibre. We have considered running fibre/coax but there is too much construction activity and other property in the way. I'm looking into RouterBOARD right now, considering a RB433AH and R52H wireless card, but I'm not sure this will actually solve the problem. It's difficult to determine if the issue is with the antennas or access points (for example, after a good thunderstorm, the wireless link will be down for at least 12 hours, but will fix itself eventually. Resetting either access point will keep the link down for at least 30 minutes. Using an airgun on the access points tends to make them more reliable, even if they are clean and dust free. From the admin interface, each access point will report seeing a very good and strong signal from the other, yet they refuse to communicate until they feel like it a few hours later.) Any suggestions welcome. I'm sure you can tell cost is a bit of a factor here but it will be easy for me to justify a higher price if I'm confident it will be effective. While I'm at it, I've been reading along on the list for over a year now; thanks everyone for sharing your real world experiences :) Peter
Re: Wireless bridge
Pair of Ubuquiti power station 2 or 5 bridges, 5 would be preferable, under $200 per end. http://www.ubnt.com/downloads/ps5_datasheet.pdf Peter Boone wrote: > Hi NANOG, > > I'm looking for some equipment recommendations for a wireless bridge between > two locations approximately 500-800 meters apart. The current setup for this > company has been extremely unstable and slow. I don't have a lot of > experience in this area so I was hoping someone could give me a few > pointers. > > Currently, both locations are using Linksys WRT54GL's flashed with DD-WRT > firmware (Yes, 802.11g. All extra bells and whistles are disabled in the > firmware. They were set up for WDS so other wireless clients could connect > to the same access point, with varying degrees of success. Not very > important). They are connected to SmartAnt 2300-2500 MHz 14 dBi directional > antenna mounted on the roof (extended pretty high for perfect line of > sight). I'm not sure when they got these antenna exactly but I'm told it was > when WiFi was very new. The network is very small so both locations share > the same subnet (192.168.1.0/24). > > They have gone through numerous Linksys access points over the years. The > wireless settings are tweaked as best as possible, and we have found the > connection to be most stable when the TX is limited to 6-9 Mbps. > > We have explored other options as well. An internet connection at each > location + VPN is out due to very slow upstream speeds (the buildings are in > an industrial area, ADSL is the only option.) The max they offer on regular > business accounts is 800 kbps up. T1 lines are even slower and even more > expensive. They won't offer us any other solutions such as fibre. We have > considered running fibre/coax but there is too much construction activity > and other property in the way. > > I'm looking into RouterBOARD right now, considering a RB433AH and R52H > wireless card, but I'm not sure this will actually solve the problem. It's > difficult to determine if the issue is with the antennas or access points > (for example, after a good thunderstorm, the wireless link will be down for > at least 12 hours, but will fix itself eventually. Resetting either access > point will keep the link down for at least 30 minutes. Using an airgun on > the access points tends to make them more reliable, even if they are clean > and dust free. From the admin interface, each access point will report > seeing a very good and strong signal from the other, yet they refuse to > communicate until they feel like it a few hours later.) > > Any suggestions welcome. I'm sure you can tell cost is a bit of a factor > here but it will be easy for me to justify a higher price if I'm confident > it will be effective. > > While I'm at it, I've been reading along on the list for over a year now; > thanks everyone for sharing your real world experiences :) > > Peter > >
Re: Wireless bridge
> (for example, after a good thunderstorm, the wireless link will be down for > at least 12 hours, but will fix itself eventually. Sounds like there are trees in the line of sight, and maybe they are getting leafier over the years. The only solution to that is to change the path if it is possible.
RE: Wireless bridge
We're a WISP, so I have lots of experience with this kind of thing. The problem with using 2.4GHz equipment is that there's a whole lot of noise out there (run Network Stumbler sometime on a laptop with a wireless card, and you'll be shocked by just how many wi-fi APs are floating around). You didn't mention your bandwidth requirements, but I'm assuming that you're trying to get more (and spend less), so I'll only recommend unlicensed gear. For that distance, you might want to consider using a 5.2GHz radio. The FCC limits their transmit power, so they only work well in short-range applications (>2 miles or so), and 5.2GHz doesn't propagate the way that 2.4GHz does, so there tends to be much less noise in that band. The Motorola PTP400 series (http://www.motorola.com/Business/US-EN/Business+Product+and+Services/Wireless+Broadband+Networks/Point-to-Point+Bridges) is very good (Asymetric Dynamic Frequency selection means that each side can pick the best frequency to transmit on, and ARQ means that scrambled packets get handled at the wireless layer), and throughput tops out about 45Mbps (300Mbps for the PTP600 series), but they are expensive. They can be purchased in many different bands. On the lower end, we've been using Ligowave (http://www.ligowave.com), and had good results from them, for the price. They also come in many bands, and run about $3000 (for the model with an integrated panel antenna), support throughput up to 45Mbps, and also support ARQ. Hope this helps. Tim Huffman Director of Engineering Business Only Broadband, LLC O (630) 590-6012 C (630) 340-1925 t...@bobbroadband.com www.bobbroadband.com > -Original Message- > From: Peter Boone [mailto:na...@aquillar.com] > Sent: Thursday, June 18, 2009 8:06 AM > To: nanog@nanog.org > Subject: Wireless bridge > > Hi NANOG, > > I'm looking for some equipment recommendations for a wireless bridge > between > two locations approximately 500-800 meters apart. The current setup for > this > company has been extremely unstable and slow. I don't have a lot of > experience in this area so I was hoping someone could give me a few > pointers. > > Currently, both locations are using Linksys WRT54GL's flashed with DD-WRT > firmware (Yes, 802.11g. All extra bells and whistles are disabled in the > firmware. They were set up for WDS so other wireless clients could connect > to the same access point, with varying degrees of success. Not very > important). They are connected to SmartAnt 2300-2500 MHz 14 dBi > directional > antenna mounted on the roof (extended pretty high for perfect line of > sight). I'm not sure when they got these antenna exactly but I'm told it > was > when WiFi was very new. The network is very small so both locations share > the same subnet (192.168.1.0/24). > > They have gone through numerous Linksys access points over the years. The > wireless settings are tweaked as best as possible, and we have found the > connection to be most stable when the TX is limited to 6-9 Mbps. > > We have explored other options as well. An internet connection at each > location + VPN is out due to very slow upstream speeds (the buildings are > in > an industrial area, ADSL is the only option.) The max they offer on > regular > business accounts is 800 kbps up. T1 lines are even slower and even more > expensive. They won't offer us any other solutions such as fibre. We have > considered running fibre/coax but there is too much construction activity > and other property in the way. > > I'm looking into RouterBOARD right now, considering a RB433AH and R52H > wireless card, but I'm not sure this will actually solve the problem. It's > difficult to determine if the issue is with the antennas or access points > (for example, after a good thunderstorm, the wireless link will be down > for > at least 12 hours, but will fix itself eventually. Resetting either access > point will keep the link down for at least 30 minutes. Using an airgun on > the access points tends to make them more reliable, even if they are clean > and dust free. From the admin interface, each access point will report > seeing a very good and strong signal from the other, yet they refuse to > communicate until they feel like it a few hours later.) > > Any suggestions welcome. I'm sure you can tell cost is a bit of a factor > here but it will be easy for me to justify a higher price if I'm confident > it will be effective. > > While I'm at it, I've been reading along on the list for over a year now; > thanks everyone for sharing your real world experiences :) > > Peter >
RE: Wireless bridge
> (for example, after a good thunderstorm, the wireless link will be down > for at least 12 hours, but will fix itself eventually. Are you sure there's not a moisture problem in the antennae cabling? Get an SWR meter that can handle the 2.4 GHz range and make sure that SWR is very low (approaching 1:1 but certainly less than 2:1). Hook up the meter in-line at the AP. Test this after everything is wet and again when there's been a dry spell. Minimize the number of exposed connections and use dielectric grease. Any exposed connections should be well wrapped with that rubberized electricians tape first, then with regular. > Resetting either access point will keep the link down for at least 30 > minutes. This seems to point to signal quality issues. This could be interference as others have suggested. Few things to try (in order of less work, less $$$): 1.) Try different 802.11 channels. Pick one of 1, 6, or 12 as they are the only non-overlapping spectrum. Set this manually on both ends 2.) if yaggi type antennas, try changing the polarity. If it's vertical now, try horizontal or vice versa (both ends should be the same for maximum gain!) 3.) Try even higher gain "dish" style antennas (these have circular polarity) 4.) Use APs that do 802.11a or n. These are much less susceptible to interference. This probably also means changing/adding antennas. *.) Bonus idea: Google roll your own dsl (assuming both locations have the same CO). Basically: get a dry pair (no dialtone) from the telco going from location A to Location B; buy two sdsl modems and install at each end; hopefully enjoy a few-several Mb connection! ~JasonG smime.p7s Description: S/MIME cryptographic signature
RE: Wireless bridge
> From: Michael Dillon [mailto:wavetos...@googlemail.com] > > (for example, after a good thunderstorm, the wireless link will be > down for > > at least 12 hours, but will fix itself eventually. > > Sounds like there are trees in the line of sight, and maybe they are > getting > leafier over the years. The only solution to that is to change the path > if > it is possible. The line of sight is all clear, no trees. Only one building along the way has a rooftop of similar height, but the antennas are extended far above the roofline. We have used a rifle scope to confirm line of sight is all clear at all angles. > From: Tim Huffman [mailto:t...@bobbroadband.com] > We're a WISP, so I have lots of experience with this kind of thing. The > problem with using 2.4GHz equipment is that there's a whole lot of > noise out there (run Network Stumbler sometime on a laptop with a > wireless card, and you'll be shocked by just how many wi-fi APs are > floating around). > Oh I know. Luckily it's located in an industrial area just on the outskirts of the city. There isn't a lot of other WiFi (in my opinion); 3-5 total SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on which rooftop you measure from. > You didn't mention your bandwidth requirements, but I'm assuming that > you're trying to get more (and spend less), so I'll only recommend > unlicensed gear. For that distance, you might want to consider using a > 5.2GHz radio. The FCC limits their transmit power, so they only work > well in short-range applications (>2 miles or so), and 5.2GHz doesn't > propagate the way that 2.4GHz does, so there tends to be much less > noise in that band. > Bandwidth requirements aren't too picky. If it can handle minimum 9 Mbps full-duplex everyone will be happy. Of course, the faster the better. I don't know if it makes a difference or not but this is all taking place in Canada. I don't know of any regulations drastically different from the U.S's regarding frequency use here. The biggest problem I've ever had though has just been payment/shipping depending on the supplier (some don't ship to Canada or are very specific about payment methods!). Just to answer a few more questions I've been getting, the access points are located inside, connected to a small UPS. The antenna wire is a very thick coax up to the roof, BNC connectors to the access point and I'm fairly certain BNC connectors on the antenna end as well. I'll double check grounding on the poles but I'm somewhat afraid to turn it into a lightning rod. I'm fairly certain that the ground in the antenna wire is clean but again, something to double check. Rain/moisture doesn't seem to cause problems. In fact the connection is more reliable through the winter. The last 2 months here have been cold/warm, dry/wet and there's been no pattern to the stability issues. The only correlation between weather and stability that they have noticed there is lightning related. > From: Jason Gurtz [mailto:jasongu...@npumail.com] > Are you sure there's not a moisture problem in the antennae cabling? I hope I just answered most of your questions Jason. Good tips to check for too. I'll answer more of your specific questions ASAP. Thanks everyone for the responses so far on and off list. I've been getting lots of product suggestions as well as ideas for troubleshooting the current implementation for the short term. I'm working on another project for today so I've just been skimming through the responses. Later tonight I'll go through all the options in more detail and report back/answer more questions. Keep 'em coming and thanks again, Peter
RE: Wireless bridge
On Thu, 2009-06-18 at 11:54 -0400, Peter Boone wrote: > Oh I know. Luckily it's located in an industrial area just on the > outskirts > of the city. There isn't a lot of other WiFi (in my opinion); 3-5 > total > SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on > which > rooftop you measure from. 2.4 and 5GHz license-free Wifi is license free because the frequencies are shared with the ISM (Industrial/Scientific/Medical) services. In an industrial area, competing WiFi is the least of your worries. These frequencies are also used by industrial grade heating units. Got anyone in the neighbourhood running a large plastic shrink wrap machine, for example? You can't directly detect these other users with a Wifi transceiver. Depending on the nature of the interference you *might* be able to hear it directly on a scanner (if you can find one that covers those frequencies), but you really need a good spectrum analyzer to tell what's going on. Anyway, don't assume the competition for spectrum is only other Wifi units. --lyndon
RE: Wireless bridge
> The line of sight is all clear, no trees. Only one building along the way > has a rooftop of similar height, but the antennas are extended far above > the > roofline. We have used a rifle scope to confirm line of sight is all clear > at all angles. > Unfortunately, you can't necessarily rely on visual line of sight. At 800meters, the Fresnel Zone on your radio is about 14ft in diameter at the midpoint. You need to make sure that this is free of obstructions. > Oh I know. Luckily it's located in an industrial area just on the > outskirts > of the city. There isn't a lot of other WiFi (in my opinion); 3-5 total > SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on > which > rooftop you measure from. > Make sure you're using the channel that doesn't have an AP on it! > > Bandwidth requirements aren't too picky. If it can handle minimum 9 Mbps > full-duplex everyone will be happy. Of course, the faster the better. > I don't know if it makes a difference or not but this is all taking place > in > Canada. I don't know of any regulations drastically different from the > U.S's > regarding frequency use here. The biggest problem I've ever had though has > just been payment/shipping depending on the supplier (some don't ship to > Canada or are very specific about payment methods!). Canadian and US regulations are very similar in the unlicensed bands. I'd still pick 5.2GHz if you were replacing the radio. > > > Just to answer a few more questions I've been getting, the access points > are > located inside, connected to a small UPS. The antenna wire is a very thick > coax up to the roof, BNC connectors to the access point and I'm fairly > certain BNC connectors on the antenna end as well. I'll double check > grounding on the poles but I'm somewhat afraid to turn it into a lightning > rod. I'm fairly certain that the ground in the antenna wire is clean but > again, something to double check. How long is your cable run, and what kind of cable is it? It's probably LMR-400 (the most common) loses about 6.6dB of your signal for every 100 feet. Also, you should check the waterproofing on the connector at the antenna. We normally use a 'courtesy wrap' of electrical tape, followed by a thick layer of Mastic tape, followed by another layer of electrical tape. Also, check your cable for nicks or kinks. > > Rain/moisture doesn't seem to cause problems. In fact the connection is > more > reliable through the winter. The last 2 months here have been cold/warm, > dry/wet and there's been no pattern to the stability issues. The only > correlation between weather and stability that they have noticed there is > lightning related. Moisture in the cables doesn't necessarily show up during rain! That moisture can seep throughout the cable, and cause attenuation when it gets cool and the moisture condenses, for example. You haven't said what kind of antennas you are using, but if they are yagi's, they probably have very poor back-to-front ratios, which means that you could be picking up interference from behind you, or on the sides, especially if the antennas are up above the tree cover. You might try horizontal polarization on the antennas (just rotate them 90 degrees, but make sure you do it on BOTH sides!) to see if that helps. Cross-polarization is usually good for about 20dB of noise rejection. The fact that there doesn't seem to be any pattern to your loss means that it's probably either interference (somebody changing channels), hardware failure, or software failure. Hope this helps. -- Tim Huffman Director of Engineering Business Only Broadband, LLC O (630) 590-6012 C (630) 340-1925 t...@bobbroadband.com www.bobbroadband.com
RE: Wireless bridge
To come up with an accurate recommendation one really needs to know your budget, on that distance speeds up to 1 gbit/sec are possible if you spend enough on the radios...Do you have some cost and desired throughput parameters to guide everyone's recommendations? -Original Message- From: Tim Huffman [mailto:t...@bobbroadband.com] Sent: Thursday, June 18, 2009 9:27 AM To: nanog@nanog.org Subject: RE: Wireless bridge > The line of sight is all clear, no trees. Only one building along the way > has a rooftop of similar height, but the antennas are extended far above > the > roofline. We have used a rifle scope to confirm line of sight is all clear > at all angles. > Unfortunately, you can't necessarily rely on visual line of sight. At 800meters, the Fresnel Zone on your radio is about 14ft in diameter at the midpoint. You need to make sure that this is free of obstructions. > Oh I know. Luckily it's located in an industrial area just on the > outskirts > of the city. There isn't a lot of other WiFi (in my opinion); 3-5 total > SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on > which > rooftop you measure from. > Make sure you're using the channel that doesn't have an AP on it! > > Bandwidth requirements aren't too picky. If it can handle minimum 9 Mbps > full-duplex everyone will be happy. Of course, the faster the better. > I don't know if it makes a difference or not but this is all taking place > in > Canada. I don't know of any regulations drastically different from the > U.S's > regarding frequency use here. The biggest problem I've ever had though has > just been payment/shipping depending on the supplier (some don't ship to > Canada or are very specific about payment methods!). Canadian and US regulations are very similar in the unlicensed bands. I'd still pick 5.2GHz if you were replacing the radio. > > > Just to answer a few more questions I've been getting, the access points > are > located inside, connected to a small UPS. The antenna wire is a very thick > coax up to the roof, BNC connectors to the access point and I'm fairly > certain BNC connectors on the antenna end as well. I'll double check > grounding on the poles but I'm somewhat afraid to turn it into a lightning > rod. I'm fairly certain that the ground in the antenna wire is clean but > again, something to double check. How long is your cable run, and what kind of cable is it? It's probably LMR-400 (the most common) loses about 6.6dB of your signal for every 100 feet. Also, you should check the waterproofing on the connector at the antenna. We normally use a 'courtesy wrap' of electrical tape, followed by a thick layer of Mastic tape, followed by another layer of electrical tape. Also, check your cable for nicks or kinks. > > Rain/moisture doesn't seem to cause problems. In fact the connection is > more > reliable through the winter. The last 2 months here have been cold/warm, > dry/wet and there's been no pattern to the stability issues. The only > correlation between weather and stability that they have noticed there is > lightning related. Moisture in the cables doesn't necessarily show up during rain! That moisture can seep throughout the cable, and cause attenuation when it gets cool and the moisture condenses, for example. You haven't said what kind of antennas you are using, but if they are yagi's, they probably have very poor back-to-front ratios, which means that you could be picking up interference from behind you, or on the sides, especially if the antennas are up above the tree cover. You might try horizontal polarization on the antennas (just rotate them 90 degrees, but make sure you do it on BOTH sides!) to see if that helps. Cross-polarization is usually good for about 20dB of noise rejection. The fact that there doesn't seem to be any pattern to your loss means that it's probably either interference (somebody changing channels), hardware failure, or software failure. Hope this helps. -- Tim Huffman Director of Engineering Business Only Broadband, LLC O (630) 590-6012 C (630) 340-1925 t...@bobbroadband.com www.bobbroadband.com
RE: Wireless bridge
> -Original Message- > From: Lyndon Nerenberg [mailto:lyn...@orthanc.ca] > Sent: June 18, 2009 12:11 PM > To: Peter Boone > Cc: nanog@nanog.org > Subject: RE: Wireless bridge > > On Thu, 2009-06-18 at 11:54 -0400, Peter Boone wrote: > > Oh I know. Luckily it's located in an industrial area just on the > > outskirts > > of the city. There isn't a lot of other WiFi (in my opinion); 3-5 > > total > > SSIDs spread across 2 of the 3 physical channels (1,6,11) depending > on > > which > > rooftop you measure from. > > 2.4 and 5GHz license-free Wifi is license free because the frequencies > are shared with the ISM (Industrial/Scientific/Medical) services. In an > industrial area, competing WiFi is the least of your worries. These > frequencies are also used by industrial grade heating units. Got anyone > in the neighbourhood running a large plastic shrink wrap machine, for > example? Within range of the beam, not that I know of. The biggest building is just a supplier, there's 2 other small buildings, not 100% sure what they do though. > You can't directly detect these other users with a Wifi transceiver. > Depending on the nature of the interference you *might* be able to hear > it directly on a scanner (if you can find one that covers those > frequencies), but you really need a good spectrum analyzer to tell > what's going on. > > Anyway, don't assume the competition for spectrum is only other Wifi > units. > > --lyndon I don't have a spectrum analyzer available to me (I've found a USB one for $200 designed for WiFi that will pick up any non-wifi noise around the frequency range too). Each access point reports a good signal. From what I recall (not on site today) the noise is very minimal. Noise anywhere from -98 to -85 with the signal at -20 to -40. The SNR is 30+, even when the connection isn't working. The DDWRT firmware reports a Signal Quality as a percentage as well: it's generally high, 80%+ (not sure exactly how it's calculated though, I've seen it fluctuate while the Signal and Noise remain about the same). These readings are consistent at both access points, and remain about the same on each of the 3 physical channels. Hard to tell for sure since the firmware doesn't keep any averages or historical statistics on the signals, and no one has the time to sit around and take a reading every few minutes. Peter
Re: Wireless bridge
Jason Gurtz wrote: Are you sure there's not a moisture problem in the antennae cabling? Get an SWR meter that can handle the 2.4 GHz range and make sure that SWR is very low (approaching 1:1 but certainly less than 2:1). Hook up the meter in-line at the AP. Test this after everything is wet and again when there's been a dry spell. Minimize the number of exposed connections and use dielectric grease. Use dielectric grease sparingly on the outer threads of the connector. Don't let it get in contact with the inside where it bridges the center pin and the shield. This will cause nasty impedance bumps. The inside of the connector should be dry. The grease on the threads helps to ensure this. Any exposed connections should be well wrapped with that rubberized electricians tape first, then with regular. Yep, the stretchy stuff. 3M type 23. -- Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV
Re: Wireless bridge
> Jason Gurtz wrote: > >> Are you sure there's not a moisture problem in the antennae cabling? Get >> an SWR meter that can handle the 2.4 GHz range and make sure that SWR is >> very low (approaching 1:1 but certainly less than 2:1). Hook up the >> meter >> in-line at the AP. Test this after everything is wet and again when >> there's been a dry spell. Minimize the number of exposed connections and >> use dielectric grease. Alternatively using an antenna with integrated ap like the one's I referred to previously (they have a nice cast enclosure for radio and a screw down bulkhead with gasket for the cable) eliminates the need for runs of rf coax at all and also deals handily with the necessity for an outdoor enclosure for the linksys ap. I would use outdoor rated cat-5 for the run up to the ap.
Re: Wireless bridge
Lyndon Nerenberg wrote: On Thu, 2009-06-18 at 11:54 -0400, Peter Boone wrote: Oh I know. Luckily it's located in an industrial area just on the outskirts of the city. There isn't a lot of other WiFi (in my opinion); 3-5 total SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on which rooftop you measure from. 2.4 and 5GHz license-free Wifi is license free because the frequencies are shared with the ISM (Industrial/Scientific/Medical) services. In an industrial area, competing WiFi is the least of your worries. These frequencies are also used by industrial grade heating units. Got anyone in the neighbourhood running a large plastic shrink wrap machine, for example? Motion sensors also run in the 2.4GHz range. You can't directly detect these other users with a Wifi transceiver. Depending on the nature of the interference you *might* be able to hear it directly on a scanner (if you can find one that covers those frequencies), but you really need a good spectrum analyzer to tell what's going on. Anyway, don't assume the competition for spectrum is only other Wifi units. --lyndon
Re: Wireless bridge
Might I suggest Ubnt.com ? Or a vendor that I use http://www.wlanparts.com/category/ubiquiti/ Couple of these http://www.wlanparts.com/product/BULLET2-D13/Ubiquiti_BULLET2_and_13dBi_24GHz_Panel_Antenna__BULLET2D13.html (100.00 per side or so). Peter Boone wrote: Hi NANOG, I'm looking for some equipment recommendations for a wireless bridge between two locations approximately 500-800 meters apart. The current setup for this company has been extremely unstable and slow. I don't have a lot of experience in this area so I was hoping someone could give me a few pointers. Currently, both locations are using Linksys WRT54GL's flashed with DD-WRT firmware (Yes, 802.11g. All extra bells and whistles are disabled in the firmware. They were set up for WDS so other wireless clients could connect to the same access point, with varying degrees of success. Not very important). They are connected to SmartAnt 2300-2500 MHz 14 dBi directional antenna mounted on the roof (extended pretty high for perfect line of sight). I'm not sure when they got these antenna exactly but I'm told it was when WiFi was very new. The network is very small so both locations share the same subnet (192.168.1.0/24). They have gone through numerous Linksys access points over the years. The wireless settings are tweaked as best as possible, and we have found the connection to be most stable when the TX is limited to 6-9 Mbps. We have explored other options as well. An internet connection at each location + VPN is out due to very slow upstream speeds (the buildings are in an industrial area, ADSL is the only option.) The max they offer on regular business accounts is 800 kbps up. T1 lines are even slower and even more expensive. They won't offer us any other solutions such as fibre. We have considered running fibre/coax but there is too much construction activity and other property in the way. I'm looking into RouterBOARD right now, considering a RB433AH and R52H wireless card, but I'm not sure this will actually solve the problem. It's difficult to determine if the issue is with the antennas or access points (for example, after a good thunderstorm, the wireless link will be down for at least 12 hours, but will fix itself eventually. Resetting either access point will keep the link down for at least 30 minutes. Using an airgun on the access points tends to make them more reliable, even if they are clean and dust free. From the admin interface, each access point will report seeing a very good and strong signal from the other, yet they refuse to communicate until they feel like it a few hours later.) Any suggestions welcome. I'm sure you can tell cost is a bit of a factor here but it will be easy for me to justify a higher price if I'm confident it will be effective. While I'm at it, I've been reading along on the list for over a year now; thanks everyone for sharing your real world experiences :) Peter
Re: Wireless bridge
+1 for Ubnt gear! Joel Jaeggli wrote: Pair of Ubuquiti power station 2 or 5 bridges, 5 would be preferable, under $200 per end. http://www.ubnt.com/downloads/ps5_datasheet.pdf Peter Boone wrote:
Re: Wireless bridge
2.4 and 5GHz license-free Wifi is license free because the frequencies are shared with the ISM (Industrial/Scientific/Medical) services. In an industrial area, competing WiFi is the least of your worries. These frequencies are also used by industrial grade heating units. Got anyone in the neighbourhood running a large plastic shrink wrap machine, for example? Good point. You can't directly detect these other users with a Wifi transceiver. Depending on the nature of the interference you *might* be able to hear it directly on a scanner (if you can find one that covers those frequencies), but you really need a good spectrum analyzer to tell what's going on. Check out http://www.ubnt.com/airview/ for a decent one. There is also wispy.
Re: Wireless bridge
Peter Boone wrote: From: Michael Dillon [mailto:wavetos...@googlemail.com] (for example, after a good thunderstorm, the wireless link will be down for at least 12 hours, but will fix itself eventually. Sounds like there are trees in the line of sight, and maybe they are getting leafier over the years. The only solution to that is to change the path if it is possible. The line of sight is all clear, no trees. Only one building along the way has a rooftop of similar height, but the antennas are extended far above the roofline. We have used a rifle scope to confirm line of sight is all clear at all angles. Given that you have optical line of sight, and that your path length is only 800m, have you considered line-of-sight optical links for this application? -- Neil
Re: Wireless bridge
Couple of comments: Regarding ISM spectrum sharing: the 2.4 GHZ band (2400-2500 MHz) and the 5.8 GHz (5725-5875 MHz) are certainly shared with ISM devices- microwave ovens, induction heaters, etc. However, the 5.2 and 5.4 GHz unlicensed bands (UNII) are not shared with ISM devices. However, these bands are subject to FCC regulations that mandate radar sensing and avoidance. This means that if your radios detect the signature of a military radar system on their active channel, they will automatically shut down and begin a waiting period before switching to another channel. Mandatory 60 second outage. There are generally three classes of point-to-point high speed unlicensed data radio gear out there today: 1. Wi-fi based gear with some additional hardware and a user interface suitable for point-to-point use. Ubiquiti, Tranzeo, HGA, etc. Pretty self-explanatory. Sub-1000 range. 2. Gear using a wi-fi chipeset (Atheros, Broadcom, etc.) with a proprietary firmware load. Trango, Alvarion, Ligowave, etc. $2000-5000 range. 3. Gear using a custom designed RF interface. Motorola, Dragonwave, etc. Given your requirements, I'd encourage you to look at classes 2 and 3. Getting any decent amount of reliability from vanilla 802.11 equipment is (as you've found) difficult. Gear in categories 2 and 3 from above will generally have a built in spectrum analyzer of some sort that will be able to see interference not caused by 802.11 devices, performance monitoring systems (BER reporting, event logs, etc), SNMP capability, etc. Definitely choose a system with an integrated antenna. You want a directional antenna such as a patch array (panel) integrated with the radio. Messing around with RF cabling, connectors, etc. is not necessary with what you're trying to do. Minimize the potential points of failure. Lightning protection is a concern. Most of this gear is PoE powered, so you'll have a single cat-5 going to the roof. Make sure it's protected with an Ethernet surge suppressor that is properly grounded. Follow the radio manufacturer's recommendations here. Your antenna mount must also be grounded according to NEC requirements. The Motorola PTP400 series radio that was recommended is one of the best unlicensed point to point radios out there. However, it's been EOL'd and replaced by the PTP500. Seems like these are both out of your budget, though. As an alternative, you might consider looking at the Trango TLink45. This radio uses a proprietary firmware and an Atheros WiFi chipset. It has a rudimentary spectrum analyzer, SNMP, ARQ (important), and adaptive rate modulation. It also has a dual-polarity software switchable antenna. This greatly increases your ability to avoid interference. It will run in the 5.3, 5.4, or 5.8 GHz unlicensed bands. They retail at about $4000 for a pair, but Trango routinely runs specials. They were on special for $1700 per pair in April. The WISPA list is a great resource for help with projects like this. Patrick Shoemaker Vector Data Systems LLC shoemak...@vectordatasystems.com office: (301) 358-1690 x36 http://www.vectordatasystems.com Message: 6 Date: Thu, 18 Jun 2009 13:13:17 -0400 From: Curtis Maurand Subject: Re: Wireless bridge To: Lyndon Nerenberg Cc: nanog@nanog.org, Peter Boone Message-ID: <4a3a75ad.8090...@xyonet.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Lyndon Nerenberg wrote: > On Thu, 2009-06-18 at 11:54 -0400, Peter Boone wrote: > >> Oh I know. Luckily it's located in an industrial area just on the >> outskirts >> of the city. There isn't a lot of other WiFi (in my opinion); 3-5 >> total >> SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on >> which >> rooftop you measure from. >> > > 2.4 and 5GHz license-free Wifi is license free because the frequencies > are shared with the ISM (Industrial/Scientific/Medical) services. In an > industrial area, competing WiFi is the least of your worries. These > frequencies are also used by industrial grade heating units. Got anyone > in the neighbourhood running a large plastic shrink wrap machine, for > example? > > Motion sensors also run in the 2.4GHz range. > You can't directly detect these other users with a Wifi transceiver. > Depending on the nature of the interference you *might* be able to hear > it directly on a scanner (if you can find one that covers those > frequencies), but you really need a good spectrum analyzer to tell > what's going on. > > Anyway, don't assume the competition for spectrum is only other Wifi > units. > > --lyndon > > >
RE: Wireless bridge
On Thu, 2009-06-18 at 09:34 -0700, John van Oppen wrote: > -Original Message- > From: Tim Huffman [mailto:t...@bobbroadband.com] > Sent: Thursday, June 18, 2009 9:27 AM > To: nanog@nanog.org > Subject: RE: Wireless bridge > > > The line of sight is all clear, no trees. Only one building along > the > way > > has a rooftop of similar height, but the antennas are extended far > above > > the > > roofline. We have used a rifle scope to confirm line of sight is all > clear > > at all angles. > > > > Unfortunately, you can't necessarily rely on visual line of sight. At > 800meters, the Fresnel Zone on your radio is about 14ft in diameter at > the midpoint. You need to make sure that this is free of obstructions. > Not only that, the radios may actually be screaming at each other at those distances which will affect performance
Re: Wireless bridge
Once upon a time, Peter Boone said: > I'll double check > grounding on the poles but I'm somewhat afraid to turn it into a lightning > rod. If it is a high point on a roof, it is a lightning rod already. You ground the antenna and mount to give the lightning a better path to ground than running through your coax and equipment. -- Chris Adams Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble.
RE: Wireless bridge
OK, from reading all the excellent feedback I've got on and off list I've attempted to compile a "quick" summary of findings/ideas/products so far. - RouterBoard is no good for this type of application. - Get a unit with radio/antenna integrated, PoE from inside the building (outdoor rated cat5, shielded I assume), lightning suppression for the PoE (properly grounded), and ensure the mast is properly grounded. - Get off the 2.4 GHz range. Move up to 5. As for licensed vs. unlicensed, I'm getting mixed input. I'm fairly certain that if the price is right and the frequency is 5GHz+, it won't be a factor. Also, I'll be very glad to separate the bridge from the client access points so that allows for more options. Every solution at this range can easily do 20+ Mbps so throughput is no longer a factor. - Products that support ARQ are highly recommended. - I'm hearing the same products mentioned over and over: - Motorola - Ubiquiti - Aironet (Cisco) - Aruba A number of individuals recommended products from other brands at low cost that meet these mentioned requirements too. I'm not going to bother with a spectrum analyzer. In the current implementation we tried channels 1, 6 and 11 for a few days at a time and found 1 to be the most reliable. Done. At this point an analyzer will tell me what I already suspect: there's a problem. I've researched the Fresnel zones and calculated out a few things with rough numbers and worst case. For one, the Fresnel zone is disrupted most if the obstruction is closer to the endpoints (e.g. antennas). In this case, this is fine as the antenna are mounted at the outermost corner of the buildings as close as possible to the other buildings, approximately 3 floors in the air. Other buildings become a factor near the middle. Based on channel 1's wavelength of 0.12438 m, and assuming 1 km apart (for simplicity sake. It's actually less), the Fresnel zone is largest in the center at approx 5.6 m radius. That could definitely be obstructed by rooftops, I'll have to take another look though. This radius cuts in half when the frequency is doubled, thus more evidence in favour of the 5 GHz+ range. Cool. Or we could just go with a good line of sight optical solution but they look too expensive, and this area can have very unforgiving fog/wind to disrupt things further. What if we tilt each existing antenna up towards the sky 10-20 degrees? Please correct me if I'm wrong. The current antennas are plates. I'm pretty sure they are polarized. I used to have a product sheet on these but a Google search doesn't turn up any useful results anymore (SmartAnt PCW24-03014-BFL). The way they are mounted to the poles might make it difficult to try rotating them 90 degrees, but worth another look. The coax between the AP and antennas are no longer than 30 feet. I've often wondered if a Pringle or Coffee Cantenna would work better than these! For right now I'll have the coax line and ends inspected for damage/softspots, check the grounding, and cover/re-cover the ends in large amounts of rubber/electric tape. I think we might try the Ubiquiti Bullet2 for approx $100 per side (PoE supply/lightning suppression, wiring included) and see what happens! If that doesn't work, no major loss and we'll move up to something more serious (the PoE and wiring will already be ready to go). I will have to look into pricing on some of these suggestions and figure out if we should even bother getting a Bullet but instead go straight to a better all-in-one solution. Thank you guys very much for the tips. Feel free to keep them coming! Peter
Re: Wireless bridge
Peter Boone wrote: > - Get a unit with radio/antenna integrated, PoE from inside the building > (outdoor rated cat5, shielded I assume), Actually shielding doesn't matter so much and it requires that the rj45 connector and socket be similarly sheilded to be effective, the salient points are: uv stablized and gel filled. normally comes in 1000' or longer rolls but something like the following will do if you're not running more than two cables ever: http://www.fab-corp.com/product.php?productid=16285&cat=296&page=1 > lightning suppression for the PoE > (properly grounded), and ensure the mast is properly grounded. excellent plan.
Re: Wireless bridge
I didn't read through all of the replies to see if this was suggested, apologies if it was. http://www.solectek.com/products.php?prod=sw7k&page=feat I implemented a PTP link at about 3 miles using these Solectek radios. I get 40Mbps consistently with TCP traffic and ~100Mbps UDP. This PTP link has literally been up for 3 years (in 2 weeks) without failing. I live in a 4 seaons state, so its seen all sorts of weather over those years. I have clean line of site down the freeway for what its worth. Its natively powered via POE, power injector included. We run all sorts of usual business application over this link, including about 30 simultaneous VOIP channels, and have not had one issue with stability. I was also told by the VAR that sold us the product that a city nearby (can't remember which one) connects all of its municipal buildings with Solectek stuff and runs its VOIP infrastructure over it as well. We run it in bridged mode with routers on each end, but it does support some rudimentary L3 stuff, static routing and RIP. IIRC, they were not "cheap" (couple of 1k), but for us have definitely been much cheaper than private circuits from carriers of comparable throughput capacity. Hope its helpful. --Justin
Re: Wireless bridge
Justin Sharp wrote: I didn't read through all of the replies to see if this was suggested, apologies if it was. http://www.solectek.com/products.php?prod=sw7k&page=feat I implemented a PTP link at about 3 miles using these Solectek radios. I get 40Mbps consistently with TCP traffic and ~100Mbps UDP. This PTP link has literally been up for 3 years (in 2 weeks) without failing. I live in a 4 seaons state, so its seen all sorts of weather over those years. I have clean line of site down the freeway for what its worth. Its natively powered via POE, power injector included. We run all sorts of usual business application over this link, including about 30 simultaneous VOIP channels, and have not had one issue with stability. I was also told by the VAR that sold us the product that a city nearby (can't remember which one) connects all of its municipal buildings with Solectek stuff and runs its VOIP infrastructure over it as well. We run it in bridged mode with routers on each end, but it does support some rudimentary L3 stuff, static routing and RIP. IIRC, they were not "cheap" (couple of 1k), but for us have definitely been much cheaper than private circuits from carriers of comparable throughput capacity. Hope its helpful. --Justin I have to say I did a double take on your speed claims. We use Solectek all over the place and have yet to archived those speeds on any of our links. Not only that Solectek engineers have told us that at a 108mbps radio rate realistically you are only going to see only 35mbps data rate on link that's just a mile apart; further you go the less bandwidth you will have. Other then that, I agree they are nice radios and even include heaters in them to help maintain temperatures above freezing during winter time so that ice buildup doesn't cause a problem. Bret
RE: Wireless bridge
Peter, to follow up on a few of your RF questions here: The idea behind the Fresnel zones is that objects (larger than one wavelength, a few centimeters at the frequencies we're dealing with here) within the zones will reflect the incoming radio wave from the transmitting radio. As seen by the receiver, there will be two signals- one coming directly from the transmitting antenna, and the reflection coming from the object in the Fresnel zone. The reflected signal, having a longer overall path length, will be slightly out of phase compared to the direct wave, and will destructively interfere with the direct wave, lowering the overall received power level seen by the receiving radio. This is called multipath interference. Therefore, unless you're using very high gain antennas (large parabolic dishes) with high directivity, you won't gain anything by pointing them at the sky or away from the object in the Fresnel zone. You'll lose more signal by mis-aiming the antennas than you will lose from the multipath interference. Regarding antenna polarization, your flat panel antennas are certainly polarized and must be oriented in the same polarization at each end. Finally, if you have a way to check the received power level at your existing radios, you will want to adjust the transmitter output power of each end so that the received power is within a reasonable range. Generally speaking, for a link of that distance, you should aim for something in the -60 dBm range. Anything hotter than a -50 and you start to get into front-end overload territory, and anything weaker than a -70 and you're beginning to run on thin fade margins. Also, I disagree that shielded Ethernet cable is unnecessary. For the very low additional cost of shielded outdoor cat-5, it's well worth your effort if you're running new cable. Of course every installation is different, but why risk ethernet errors due to some large air conditioner or something on the roof spewing EMI? Patrick Shoemaker Vector Data Systems LLC shoemak...@vectordatasystems.com office: (301) 358-1690 x36 http://www.vectordatasystems.com Message: 12 Date: Thu, 18 Jun 2009 21:46:08 -0400 From: "Peter Boone" Subject: RE: Wireless bridge To: Message-ID: <23ab01c9f07f$b7aa6480$26ff2d...@com> Content-Type: text/plain; charset="us-ascii" OK, from reading all the excellent feedback I've got on and off list I've attempted to compile a "quick" summary of findings/ideas/products so far. - RouterBoard is no good for this type of application. - Get a unit with radio/antenna integrated, PoE from inside the building (outdoor rated cat5, shielded I assume), lightning suppression for the PoE (properly grounded), and ensure the mast is properly grounded. - Get off the 2.4 GHz range. Move up to 5. As for licensed vs. unlicensed, I'm getting mixed input. I'm fairly certain that if the price is right and the frequency is 5GHz+, it won't be a factor. Also, I'll be very glad to separate the bridge from the client access points so that allows for more options. Every solution at this range can easily do 20+ Mbps so throughput is no longer a factor. - Products that support ARQ are highly recommended. - I'm hearing the same products mentioned over and over: - Motorola - Ubiquiti - Aironet (Cisco) - Aruba A number of individuals recommended products from other brands at low cost that meet these mentioned requirements too. I'm not going to bother with a spectrum analyzer. In the current implementation we tried channels 1, 6 and 11 for a few days at a time and found 1 to be the most reliable. Done. At this point an analyzer will tell me what I already suspect: there's a problem. I've researched the Fresnel zones and calculated out a few things with rough numbers and worst case. For one, the Fresnel zone is disrupted most if the obstruction is closer to the endpoints (e.g. antennas). In this case, this is fine as the antenna are mounted at the outermost corner of the buildings as close as possible to the other buildings, approximately 3 floors in the air. Other buildings become a factor near the middle. Based on channel 1's wavelength of 0.12438 m, and assuming 1 km apart (for simplicity sake. It's actually less), the Fresnel zone is largest in the center at approx 5.6 m radius. That could definitely be obstructed by rooftops, I'll have to take another look though. This radius cuts in half when the frequency is doubled, thus more evidence in favour of the 5 GHz+ range. Cool. Or we could just go with a good line of sight optical solution but they look too expensive, and this area can have very unforgiving fog/wind to disrupt things further. What if we tilt each existing antenna up towards the sky 10-20 degrees? Please correct me if I'm wrong. The current antennas are plates. I'
Re: Wireless bridge
Hello -
On this same topic does anyone have any experience with the Linksys
WAP200E?
thanks and regards
Hugh
On 19 Jun 2009, at 20:19, Bret Clark wrote:
Justin Sharp wrote:
I didn't read through all of the replies to see if this was
suggested, apologies if it was.
http://www.solectek.com/products.php?prod=sw7k&page=feat
I implemented a PTP link at about 3 miles using these Solectek
radios. I get 40Mbps consistently with TCP traffic and ~100Mbps
UDP. This PTP link has literally been up for 3 years (in 2 weeks)
without failing. I live in a 4 seaons state, so its seen all sorts
of weather over those years. I have clean line of site down the
freeway for what its worth. Its natively powered via POE, power
injector included. We run all sorts of usual business application
over this link, including about 30 simultaneous VOIP channels, and
have not had one issue with stability. I was also told by the VAR
that sold us the product that a city nearby (can't remember which
one) connects all of its municipal buildings with Solectek stuff
and runs its VOIP infrastructure over it as well.
We run it in bridged mode with routers on each end, but it does
support some rudimentary L3 stuff, static routing and RIP.
IIRC, they were not "cheap" (couple of 1k), but for us have
definitely been much cheaper than private circuits from carriers of
comparable throughput capacity.
Hope its helpful.
--Justin
I have to say I did a double take on your speed claims. We use
Solectek all over the place and have yet to archived those speeds on
any of our links. Not only that Solectek engineers have told us that
at a 108mbps radio rate realistically you are only going to see only
35mbps data rate on link that's just a mile apart; further you go
the less bandwidth you will have.
Other then that, I agree they are nice radios and even include
heaters in them to help maintain temperatures above freezing during
winter time so that ice buildup doesn't cause a problem.
Bret
NB:
Have you read the reference manual ("doc/ref.html")?
Have you searched the mailing list archive (www.open.com.au/archives/radiator)?
Have you had a quick look on Google (www.google.com)?
Have you included a copy of your configuration file (no secrets),
together with a trace 4 debug showing what is happening?
Have you checked the RadiusExpert wiki:
http://www.open.com.au/wiki/index.php/Main_Page
--
Radiator: the most portable, flexible and configurable RADIUS server
anywhere. Available on *NIX, *BSD, Windows, MacOS X.
Includes support for reliable RADIUS transport (RadSec),
and DIAMETER translation agent.
-
Nets: internetwork inventory and management - graphical, extensible,
flexible with hardware, software, platform and database independence.
-
CATool: Private Certificate Authority for Unix and Unix-like systems.
Re: Wireless bridge
2009/6/19 Peter Boone > > - Get off the 2.4 GHz range. Move up to 5. As for licensed vs. unlicensed, > I'm getting mixed input. I'm fairly certain that if the price is right and > the frequency is 5GHz+, it won't be a factor. Also, I'll be very glad to > separate the bridge from the client access points so that allows for more > options. Every solution at this range can easily do 20+ Mbps so throughput > is no longer a factor. > It looks like your fresnel zone is 14ft (according to a previous poster) and you're currently using relatively low power radio waves. Have you considered using something like Free Space Optics? For under $100, you can build yourself a couple of RONJAs[1] and test out what the signal is going to be like - that runs at 10Mbit, and can stay in place as a backup once you then buy a FSO device from a proper manufacturer (MRV make some nice ones) and you're looking at 100Mbit for some money, 1000Mbit for quite a lot of money and 1Mbit for "it would have been cheaper to lay fiber". I'd heartily recommend giving infra-red FSO a go, no Fresnel zone and it's essentially bridged ethernet - no funky routing required, though I would still set up OSPF or similar with it, to fail back to a slower link such as the RONJA. Matthew Walster [1] http://ronja.twibright.com/
Re: Wireless bridge
Matthew Walster wrote: I'd heartily recommend giving infra-red FSO a go, no Fresnel zone... A nitpick, but there's nothing special about infra-red that makes it not electromagnetic just like microwave. So there's still a Fresnel zone, only smaller in diameter. Also for this kind of link, 60 GHz gear is often cheaper and easier to deal with, so what I would recommend. Matthew Kaufman
Re: Wireless bridge
> Also for this kind of link, 60 GHz gear is often cheaper and easier to deal > with, so what I would recommend. I'd also take a look at 60GHz, check http://www.bridgewave.com/, I believe they have some sort of promotion going on for 60/80GHz gear. My .02
Re: Wireless bridge
You've got to recall that the genesis of this is dicsussion was the replacement of a pair for open-wrtized linksys wrt-54g routers, which have 30mW 2.4ghz radios being used for an 800meter link... There are a vast continuum (both in terms of performance and cost) of solutions between that and a pair of 60ghz mm wave part 15 radios. joel Jorge Amodio wrote: >> Also for this kind of link, 60 GHz gear is often cheaper and easier to deal >> with, so what I would recommend. > > I'd also take a look at 60GHz, check http://www.bridgewave.com/, > I believe they have some sort of promotion going on for 60/80GHz gear. > > My .02 >
