a company has just setup a wireless connection for us. The setup is as following:
The distance between objects is 1.5km, there is one building between the two buidlings that is 5 meters higher:
Object "A" a "Redline AN-50", whitch operates on 5.4Ghz, 36Mb/s and setup as accesspoint. Object "B1" a Redline (same device) but setup as a repeater. Object "B2" a Cisco Aironet 350, 2.4Ghz. 11Mb/s setup as repeater. Object "C" the same Aironet setup as AP.
The ping results are good, 9ms peeks to 32ms. But when testing the speed by copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s. Avarages at 12KB/s
Could there be a misconfiguration of the hardware, or what can be the problem here. If someone can hint me, please.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
Those Redline products (really nice, by the way) are supposed to support up to 48Mbs sustained throughput. Somebody definitely screwed the pooch on that project. I can't imagine the reasoning of having a Cisco 802.11b (about 5-7 Mbs sustained) in the chain. If you're going to spend the money for two Redlines, you lose the benefit by using a Cisco in the chain. You could contact Redline directly for assistance, but I think the company that did this for you has some 'splainin to do. As for what's actually wrong, do you know the link quality and signal strength for these links? Is there a lot of RF noise in your area?
Setting a single device up as a repeater halves the throughput. But the Redline is so much faster than the Cisco, you only have to think about the Cisco. It's data rate may be getting cut in half. Unless you mean that the Redline and Cisco are piggy-backed on the building in the middle and work together as a repeater, in that case, they're not cut in half but have full bandwidth.
Higher than what? Do you have an obstructed line of sight? Do you have Fresnel zone clearance? If not, you're about to have a reliability problem.
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need a radius of about 7 meters clearance at midpoint. Do you have clearance?
Yeah, I know RedLine claims that the AN-50 is NLOS because it does OFDM. I think NLOS is science fiction and marketing hype.
You topology description is vague, ambiguous, and lacking in important detail. How far apart are A -> B1? (Redline) How far apart are B2 -> C? (Cisco) Which path has the building obstruction? Any other obstructions?
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Object "B1" a Redline (same device) but setup as a repeater.
Huh? Why a repeater? To what wireless device are they repeating to? Methinks this is misconfigured or you're using the wrong buzzword. Methinks both Redline boxes should be setup as a transparent bridge.
I'll make a guess(tm) and assume that B1 and B2 are located near each other and connected with an ethernet cable. Is this correct?
The Cisco 350 doesn't act as a repeater so methinks you're using the wrong term here. There are also multiple models of the Cisco 350. My guess(tm) is that both Cisco 350's should be setup as wireless transparent bridges.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
9msec for such a system sucks. Something is wrong. Even the most disgusting point to point wireless 802.11b link will do Could there be a misconfiguration of the hardware, or what can
This is a rather poor design. You have a top of the line, premo
5.6Ghz wireless bridge running in an obstructed path. It's capeable of doing 48Mbits/sec thruput, but you have it throttled with a pair of comparatively slow 802.11b bridges which are limited to perhaps
5Mbits/sec on a good day, and probably 3Mbits/sec typically. Even if it had worked as intended, it still would be running well under expectations. Methinks you need to yell at whomever sold you this mess.
Divide the puzzle in half. Plant yourself with a laptop at B1-B2 and unplug each end. Ping away in both directions and see which part of the link is having a problem. It could easily be both. Then, ask the experts that sold you this abomination why they left without any real thruput testing.
What does this thing do? What level of sustained thruput are you expecting?
Coax as in RG-58a/u as in 10base2 also known as Cheapernet? I do that all the time, but it's totally inappropriate for this arrangment. If they're using 10base2, it's half duplex (HDX) at
10mbit/sec. You'll get about 6Mbit/sec thruput which makes it a substantial bottleneck. The Cisco 802.11b link is slower, but if your experts decide to replace the Cisco with something that will keep up with the speed of the RedLine boxes, the coax will become the preformance bottle neck.
If there's a 10baseT to 10base2 media converter in the system, the flow control isn't setup correctly, or the ethernet interfaces in either the Cisco or RedLine boxes are setup wrong, or NWAY is screwing up again.
Yes. Yes, yes, YES! Use the tools the manufacturers supplied.
Field? Point to point (wirless bridge) has the same RF problems as any other wireless system.
They lie. They unloaded what they had in stock because you were in a rush. As long as it's temporary, I don't see a problem. Eventually, the Cisco boxes should be replaced by another pair of RedLine wireless bridges.
What are your performance expectations (i.e. thruput)? If it's more than about 3-5Mbits/sec sustained thruput, the Cisco's are a bad choice. If it's about 3-5Mbits/sec, then you overpaid for the RedLine boxes as another pair of Cisco 350's would be much cheaper.
Incidentally, do you have any clue as to the relative cost of the RedLine routers versus the Cisco routers?
No. That's not your job. That's the job of whomever sold you this conglomeration of boxes.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
Hi Roger,
The company says it should work ok, they left when they pinged the connection an saw it was oke. On monday I will get them back to find the flaw. Just was thinking it was somthing on our network.
The connection is urgent and has been setup in 3 days. There is no much noise I guess because its an area with just some company's that don;t use RF AFAIK.
I suspect its the connection from B1 to B2, this is connected with COAX over a distance of 60 meters. As for the signal strenght, could I see this in web management tool of the devices? I don't know much about RF and because its a p2p connection there would't be a field?
The reason why they used cisco for the last end bit, was because (as they say) they couldn't get another redline devices.
Could you tell me what settings I should check on the web management of the devices to make sure they have been setup right?
Building A Building B Building C A1 = Redline B1 = Redl. C1 = Cisco 350 bridge B2 = Cisco 350 bridge
So building B is higher than building C, that is why this 3 point setup is used. For what I know devices B1 and B2 are connected with a 75ohm COAX cable that spans the width of the the B building whitch is aprox 60 meters. My guess is that signal strenght is lost here.
I've read on their site that they develop their systems by a mathimatically view on the concept. And so be better :) Aren't they all since it's all about EM waves.
accesspoint.
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>Object "B1" a Redline (same device) but setup as a repeater.
I'am a non native dutchy, so the right toplogy about somthing I have no knowledge of can be a bit lacking here. Sorry about that. I'll try my best.
The distance between A and B1 is aprox 900 meters and from B2 to C is about 600 meters. There are no obstacles exept a lake between A and B1 (and a container terminal that doesn't reach above A and B, there is a lot of iron though, the containers.) This could influence the signal a little be I think.
The people who set it up told me that B1 is a repeater and also they named A1 as "office to repeater" and B2 "repeater to office" So they would be all transparent bridges? Makes much more sence indeed.
B1 and B2 are mounted on both sides of the middle builidng roof and are connected with a COAX cable. (not sure).
correct, they are bridges with a horrible web admin interface.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
Even worse, today (i was at the site for a half hour) the pings would go up to 1500, 3000 ms and back to 6ms. And other times stay just below
50ms. Very weird situation.
Good tip. But what if B1 or B2 is a faulty one. I would get bad ping results from A or C, because they have to go trough B1/2. A traceroute would workaround this, not?
Beter yet, the whole thing costs 10.000 euro's. I will call them tomorrow but have no fate in them fixing it.
It's a backup for a fixed line whitch will arive within a month. We thought to bridge this perion with wifi. Sharing files with the fileserver on the other end would be great, but with this transfer rates this is not possible. Most important thing is stable connectivity with an AS400 application.
I for havn't had any time to sit down and look for the problem. Tomorrow I'll have that and have to fix this. I'll follow you tips.
The company left all in default, the passwords still admin/admin for the redline's and the cisco's hace no authentication at all. Wonder how security is done here :) The http and telnet interface of the cisco is so bad. I can reach them by telnet now and below a paste of their configs. Maybe some misconfig can be seen here.
Redline A1: Jeff Liebermann wrote:
Hi Jeff,
let me first say that I know little about wifi and the situation makes me nosey at what is going on.
buidlings that is 5 meters higher:
There is clearance between the buildings. Let me draw the situation:
Building A Building B Building C A1 = Redline B1 = Redl. C1 = Cisco 350 bridge B2 = Cisco 350 bridge
So building B is higher than building C, that is why this 3 point setup is used. For what I know devices B1 and B2 are connected with a 75ohm COAX cable that spans the width of the the B building whitch is aprox 60 meters. My guess is that signal strenght is lost here.
I've read on their site that they develop their systems by a mathimatically view on the concept. And so be better :) Aren't they all since it's all about EM waves.
accesspoint.
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>Object "B1" a Redline (same device) but setup as a repeater.
I'am a non native dutchy, so the right toplogy about somthing I have no knowledge of can be a bit lacking here. Sorry about that. I'll try my best.
The distance between A and B1 is aprox 900 meters and from B2 to C is about 600 meters. There are no obstacles exept a lake between A and B1 (and a container terminal that doesn't reach above A and B, there is a lot of iron though, the containers.) This could influence the signal a little be I think.
The people who set it up told me that B1 is a repeater and also they named A1 as "office to repeater" and B2 "repeater to office" So they would be all transparent bridges? Makes much more sence indeed.
B1 and B2 are mounted on both sides of the middle builidng roof and are connected with a COAX cable. (not sure).
correct, they are bridges with a horrible web admin interface.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
Even worse, today (i was at the site for a half hour) the pings would go up to 1500, 3000 ms and back to 6ms. And other times stay just below
50ms. Very weird situation.
Good tip. But what if B1 or B2 is a faulty one. I would get bad ping results from A or C, because they have to go trough B1/2. A traceroute would workaround this, not?
I have no packet loss and even the stats on the devices don't have much error reporst. Couldn't find signal indicators, execpt on the redline there are just green boxes that indicate signal, power etc. All seems fine. But I did see a realtime chart on the cisco about interference. The chart was filled, just don;t know how to read it. But it indicated
70%.
Havn't had mych time to look at it, will have since this monday. The whole setup costs 10.000 euro's.
We wanted to bridge the delivery time of a fixed line, whitch is in a month. File serving with the office would be great. But most important is stable connectivity with an AS400 based application.
I have telnet access to the devices now, the last end (C1) seems down at the moment. But have copied some data from the others (even authentication is left as is to default, cisco got no auth at all).
Please see:
Redline A1:
AN-50>show config sysname = kantoor to repeater sysdetails = ipaddr = 10.32.248.16 ipmask = 255.255.255.0 gateway = 10.32.248.1 flowctrl = off eth = 100FD http = on snmp = on telnet = on telnetport = 23 rffreq = 5535 autoscan = off dfsaction = 2 antgain = 40 txpower = 14 atpcen = on adaptmod = on modreduct = 2 ubrate = 36 master = on encrypt = on encryptkey = ### llmod = off lmu = on ll = 0 buzzer = off radio = on optionskey = ### flash 1: 1.32.003 flash 2: 1.32.011 active
System [Name ][Kantoor ] [Terminal Type ][teletype] MAC Address : 00:40:96:53:d1:6e
Config. Server [Protocol ][None ] IP [Address ][10.32.248.18 ] IP [Subnet Mask ][255.255.255.0 ] Default [Gateway ][10.32.248.1 ]
[Service Set ID (SSID) ][x ] [Role in Radio Network ][Root Bridge ] [Optimize Radio Network For ][Throughput] [Hw Radio] Ensure Compatibility With: [2Mb/sec Clients][_]
[Security Setup] [SNMP Admin. Community ][ ]
Kantoor Network Ports Uptime: 2 days, 07:03:26 ===[Diagnostics]=== ___________________________________ Name [Ethernet] [Root Radio] [Bridge:Magazijn] Status Up Up Up Mb/s 100.0 11.0 11.0 IP Addr. 10.32.248.18 10.32.248.18 10.32.248.18 MAC Addr. 00409653d16e 00409653d16e 00409653d16e
I'll try to answer your questions, but this is much too messy a problem to solve with what information is supplied. Literally everything you've supplied about the system makes me wonder what your wireless experts were thinking.
(Slight redraw. Beware of tabs.)
So far no problems as long as you have line of sight. However, I'm worried about interference pickup from the rooftop. The Redline bridges are supplied with their own directional antennas, so I'm not too worried about them. However, you didn't mention what the Cisco
350 bridges used for antennas. Hopefully they're directional and not an omnidirectional.
There's no RF in the coax cable. The coax possibly carries only data. I think you should check if it really is coax cable. There's no evidence of any media converters in this system to go from 100baseTX to 10base2 coax. In addition, the coax cable should be 50 ohms and not 75 ohms. I've used 75 ohms, but only if there was no alternative. Shielded CAT5 (required in some EU countries) looks very much like RG-6/u 75ohm coax. Check the labels.
In a past life, I played RF engineer for about 15 years. I'm not totally up to date on everything, but I consider myself rather well informed on the basics. As far as I'm concerned, Non-line-of-sight (NLOS) is a marketing term and a theoretical exercise in reassembling multipath signals into something useable. In my limited experience, almost any NLOS system can be made to work for a while. The problem is that the reflections and multipath move around as the objects involved move around. The result is fatal un-reliability. What works one day, fails the next. I can post MRTG graphs of signal strength and S/N ratio of perhaps two NLOS links that I'm forced to deal with. Huge random variations in both parameters along with signal loss for extended periods are common.
No problem. Your English is much better than my Dutch.
Sounds like an ideal path. Both links are relatively short. 900 meters is nothing compared to the maximum 80km range of the Redline. I'm a bit worried about why it has slowed down to 36Mbits/sec instead of the maximum of 72Mbits/sec. At 0.6km, I would expect it to be running at maximum speed. Lots of possible reasons including interference, reflections, and improper setup.
Well, they are correct that building B1-B2 is a repeater. B1 just repeats what it gets from B2. Likewise, B2 just repeats what it gets from B1. This is sometimes called a "back-to-back" repeater. It has the advantage of being full duplex, where it can transmit at full speed without any store and forward delays.
However, you stated that the radios were setup as repeaters. That's not possible with either Redline or BR350 bridges. In order for this system to work, *ALL* the radios must be setup as transparent bridges. By transparent, I mean that it will pass more than one MAC address allowing multiple computers to be bridged through the system.
I've seen worse. Both the Redline and the Cisco have command line interfaces. I've never played with the Redline version, but Cisco BR350 uses IOS which are messy, but powerful. There are web interfaces in both devices, but they are mostly front ends for the command line interfaces.
copying a large file from a fileserver, the download started at 30KB/s and then dropped to 8KB/s.
Think about it. If there was a nice quiet link, with no interference, the ping times would remain the same. However, if there was packet loss anywhere in the system, it would manifest itself as wide
*VARIATIONS* in ping times. Traceroute should show what part of the link is having problems. Again, I advise you to seperate testing of the various parts of the system, and NOT test the entire system until the component parts are proven reliable.
The large variations in ping time can be cause by packet loss anywhere in the system. That includes at the interfaces to the bridges, the coax mess in between bridges, NWAY failure, and wireless interference. I'll bet on interference. It's common on tall buildings overlooking areas where a large number of wireless users congregate. You might look into the location of municiple wireless networks on 2.4 and
5.7GHz. Check:
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locations.
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You can ping from the other end of the link by logging into the wireless router at the other end and pinging from there. It will be slothish due to high packet loss, but the number will be real. However, it might be best to do some travelling. 1.5km doesn't sound like much distance to walk.
That's $12,360 dollars. The hardware costs about: RedLine AN-50 boxes and antennas are $3,455 each. Cisco AIR-BR350-A-K9 bridges, plus antennas and coax, are about $600 each. for a total of about $8,100 list price plus incidentals.
I can see why they did not supply another pair of Redline routers. The total cost for 4ea Redline boxes would have been $13,780, which would have cost more than they bid on the project. There was no shortage of Redline routers. They just replaced what was necessary with whatever they had available and was cheap enough to make a profit.
I don't want to get in the middle of a debate with your vendor. The bottom line is that you paid a substantial amount of money for a system that does not work even at the minimum theoretical level (4Mbits/sec as limited by the 802.11b link). They also abandoned you to do their troubleshooting for them. If you have some financial leverage, I would use it.
Well, it's certainly not stable with ping times varying all over the place. I use the ping time (using pingprobe and MRTG) to measure the system latency of my links. When they start to vary, I know I have either excessive traffic or excessive packet loss.
File sharing is going to require some substantial bandwidth. It can be done at the theoretical limited bandwidth of 4Mbits/sec for
802.11b. It would be better if it were running at the 10 times faster speed of the Redline routers. In the US, if I want reliable operation with no suprises, I spend the money on licensed wireless, with coordination, to insure no interference.
What security? Defaults are just asking for trouble and hackers. You will not find them on the 5.7GHz Redline link, but the 802.11b 2.4Ghz link if full of hackers like me just waiting to pounce on an unsuspecting wireless link and give themselves a tour of your system.
I'll try, but I don't see any wireless (MAC layer) error statitistics. See notes with Redline A1:
There are a few errors (682) on the radio link show, but nothing serious. I would think this would be a good and reliable link. Hmmm...
The above means the signal was lost for some reason and the bridge had to reconect.
I think (not sure) that this is a WPA encryption key exchange. Not a problem.
been so busy last week to forgot to reply. You know that I metioned that the last end didn't reply on ping. It was because I reached the ethernet of B2, but the radio to C was cut.
Well in short, all that was causing trouble was a _badly_ connected connector (to the antenna) on B2. So the wind played with it resulting in some high pings, very very slow pings and no reply's at all.
So the company that was hired, is fired. For all future jobs.
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