Poor design sucks for the designer... If you build a road with a gate that opens when a car with a validated license plate pulls up, what happens when a bunch of unknown cars show up? Traffic jam... And probably accidents.
I'm just impressed the little iPhone can generate 10Mbps of traffic!
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
First, its 10 megaBIT, not megaBYTE. 10 mbit isn't that much. Especially if there is a flaw in the iPhone's IP stack. I have had single devices on my network broadcast way more traffic than that when misbehaving. This is entirely within the realm of possibility.
Its statements like yours that cause people to accuse us of being blind Apple zealot fanboys. Please, lets be open minded. Apple doesn't do everything quite perfectly.
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
Duke's network probably could be configured better to handle misbehaving devices, but let's not place all of the blame on them. If I run over someone with my car, does that mean the person I hit is at fault?
Right, I'm sure that's why they're trying to call apple, just to thank them. Or maybe they should complain because, for some reason, the iPhone is crashing their network. Would there be a reason that 18000 students with laptops or other wifi devices all work fine, but throw a few iPhones into the mix, and all of a sudden its the network's fault? Its not that the phone's are asking for a bad router address, it must be because the other routers aren't responding, even though they don't even have that address.
Then again, maybe if the folks at Duke (or, hell, UNC) stopped patting themselves on the back and congratulating themselves on how great they are, and spent time actually working, they might find the problem.
And is anyone surprised that the communication has been 'one-way'?
First, its 10 megaBIT, not megaBYTE. 10 mbit isn't that much. Especially if there is a flaw in the iPhone's IP stack. I have had single devices on my network broadcast way more traffic than that when misbehaving. This is entirely within the realm of possibility.
Its statements like yours that cause people to accuse us of being blind Apple zealot fanboys. Please, lets be open minded. Apple doesn't do everything quite perfectly.
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
Duke's network probably could be configured better to handle misbehaving devices, but let's not place all of the blame on them. If I run over someone with my car, does that mean the person I hit is at fault?
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
But then the question stands still, why aren't other people complaining about this? Wouldn't Apple's Campus wifi have seen this? Or how about any other wifi networks? I would think if the issue is simply the iPhone mucking up WiFi, that more and more people would be speaking up saying "Apple messed up".
You want us to not be so quick to lay the blame on Duke and let Apple off. So likewise, don't just eat up a single report, and write it off as Apple having made a mistake. At this point, i'd say its an unknown, with potential for both to be at fault.
I like the "flat-network" issue as the probable cause of this problem, or if not the root cause, something that is amplifying what would be a much smaller (and therefore more easily containted) problem on other networks.
I work in IT, though I'm not a network person, and I remember how our network folks were hell bent on segmenting our network into separate zones for students, labs, faculty and administrators, and our school is only ~2500 users total. Why would such a large institution such as Duke opt for a flat network setup?
Of course, it may be an iPhone with a wonky wi-fi card. I've seen bad ethernet cards flood the network, sometimes causing what the network folk call an "arp-storm". It could be that one or two bad iPhone wi-fi cards are wreaking havoc with Duke's flat setup.
I've been using my iPhone on our (segmented) network for 2 weeks, and haven't had a single problem (and our network folk are such that if anything causes a problem, they search and destroy immediately). The fact that other places aren't reporting the same problem places the blame closer to NC than to Cupertino. Unfortunately, too many higher-ed IT/network people come from the corporate world where, if it doesn't have a Microsoft logo you get the 2000 yard stare if you bring them a problem with a Mac. That's also the source of their knee-jerk "it has to be Apple's problem".
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
Or a poorly designed and implemented network that is allowing traffic looking for a "incorrect network" to continuously loop. I believe RIP without proper Poison Reverse could cause this.
I wonder what protocols and design they have? I can't find any info on the net anywhere.
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
Because it can't be a problem with the iPhone OS's network stack. It has been known that OS software can contain bugs that could cause issues. Its happened in the past.
Duke's IT group should have been more cautious about staying the iphone has problems because in the end they might be the ones with egg on their face.
Quote:
Originally Posted by Louzer
No, they shouldn't be more cautious. They already tracked down the cause: its iPhone traffic. They also know that its looking for a router that doesn't exist, and requesting continuously for that router (see, even if they are from Duke, they aren't completely clueless - but, really, we all know they're working there because they couldn't get jobs at the Univ. of Maryland).
From that perspective, they're completely correct. The iPhone is royally screwing up their network. Now, whether its because of issues with the iPhone itself, or its their network setup, is a different story.
The writer you chastise is correct you are wrong in this particular argument. Your logic is like saying ... if lying down on the sidewalk with your head in the road is a problem because cars keep hitting you then it might be an issue with the cars. The writer simply stated they should be sure what is the problem first. Moving your head would be worth a try first ...
Sure they have identified the iPhones are involved but if as the writer correctly says, IF this is because of a network screw up they might be wise to trouble shoot before publicly stating it is the FAULT of the iPhones and thus feeding trolls with fodder to repeat and exaggerate and attempt to damage Apple's reputation.
But then the question stands still, why aren't other people complaining about this? Wouldn't Apple's Campus wifi have seen this? Or how about any other wifi networks? I would think if the issue is simply the iPhone mucking up WiFi, that more and more people would be speaking up saying "Apple messed up".
There are several possibilities... Maybe Duke's network is too flat and should be segmented better. Maybe Duke is the only one saying anything. But even if both of those are the case, it doesn't excuse the behavior of the iPhone. No device should be flooding a network with ARP requests, period. Whether the network can handle it or not is not the issue here.
Apple is allowed to make a few little mistakes here and there, right? I'm sure they'll fix it. You guys are acting like there is no way in hell it could be a problem with the iPhone. Let's be a little more realistic.
The iPhone WiFi is fine, they're getting (presumably by DHCP) a router address that doesn't exist, and then looking for that router whenever they want to send traffic off the subnet.
And the netadmins haven't worked out yet where they're getting their router information from - if the network's that flat then the responsibility would seem to be with whoever's running a misconfigured DHCP server, andthe netadmins to track it down sharpish.
What's off is that other wifi connected devices getting a DHCP address on that net would work, and iPhones wouldn't.
A few things could cause that - other stuff might not actually work, they might have some DHCP strings that mean the duff DHCP server gets selected to serve them, or there could have been a change such that everything with an existing DHCP address lease retains it's (working) config, but new devices (like all the iPhones that just got bought) get the new (duff) information.
BTW, it's not an iPhone thing - any device looking for a router will keep ARPing for it until it turns up. It could be that the iPhones ARP at a ridiculously fast rate, or there's a lot of them - most IP networks have some spurious ARP traffic, but usually for non-existent hosts, rather than routers.
BTW, it's not an iPhone thing - any device looking for a router will keep ARPing for it until it turns up. It could be that the iPhones ARP at a ridiculously fast rate, or there's a lot of them - most IP networks have some spurious ARP traffic, but usually for non-existent hosts, rather than routers.
It seems like you just skimmed the article. The iPhone is trying to find the MAC addresses of IPs that don't exist on a given segment of the Duke network (the ARP flooding). It happens when the phone loses WiFi connectivity in one location and tries to reconnect in another location. When it connects to the new segment it shouldn't be flooding it with ARP requests for addresses that don't exist on that segment. This is an IP stack flaw, pure and simple. What other possible explanation is there for it?
The article also states that it is only two iPhones that are causing all of the problems. Sounds like they have really narrowed it down.
Quoting from the article: "On two occasions, one last Friday and one today, Monday 16 July, both users seemed to be behaving completely normally, yet both iPhones started flooding the net with ARP requests. In both cases, the user first successfully connected to the WLAN at one location, and then moved to another building, where the ARP flood began. 'It may have something to do with the iPhone losing connectivity and then trying to reconnect in a new location,' Miller says." This makes it pretty clear that the problem is with the iPhone. Not a lot of room for debate if you ask me.
Except that if it were *solely* the fault of the iPhone, you'd expect to see this on *any* network with multiple WAPs, as the iPhones roam. Now, it's possible that this is simply the first such report, but until the second, third, fourth, and so on appear, then it's even odds as to what portion of the system is causing the issue.
Again, I suspect that the Duke network isn't set up to gracefully handle roaming clients, *and* there very well may be an issue with the iPhone stack, and the combination of the two is causing the situation.
I just spent the last hour researching this in the original forums where the problem is being discussed. Definitely an iPhone problem... Why?
1. It isn't just happening at Duke. Other networks are seeing it too; Duke is the only one that has gotten picked up by the media so far. (And, by the way, they didn't go to the media, Network World found the discussion of the problem in a blog, and came to them to ask to publish the story.) Most other locations are banning the range of iPhone MAC addresses to prevent them from bringing their networks down. (And just because you haven't heard about it doesn't mean it isn't happening elsewhere, BTW!)
2. It isn't happening with all iPhones. It is a strange set of circumstances that trigger the problem. A given phone has to have been at three locations with similar configurations but different IP subnets successively (first at location A, then B, then C, though the specific locations of A,B and C do vary). At location C the iPhone tries to find a router that existed at location A, and sends out 30 ARP requests to find that router EVERY MILLISECOND, so each iPhone is sending out roughly 30,000 ARP requests per second.
3. It also appears that the default settings on the iPhone may not trigger the problem, that the user has to have changed the WiFi configuration to some degree, though to what degree that is remains unclear.
4. The Duke network isn't "flat" as some have suggested. It appears to have been well organized and implemented, and this is (ironically) actually contributing to the iPhone's behavior.
5. No device should EVER send out 30,000 ARP requests for the same IP address per second, no matter what the circumstances of the network it is connected to, much less when the requested IP address isn't in the iPhone's current subnet.
6. The problem ticket has been escalated at Apple to try to find a solution.
Back in my day, we didn't have fancy phones to get our e-mail. We had to wait in line for hours and log into the school internet with TELNET. We would be lucky to check our e-mail once a month. Simply typing the wrong password would shut down the entire system.
These Tweedle-Duke and Tweedle-Ding-Dongs don't know their heads from their rear ends. In my day, you were a computer genius if you were the SYSOP of a BBS.
Enough of this iPHONE shenanigans... Get your books out, walk to and from your classes uphill both ways, and study.
How is the Duke network setup exacerbating the issue? I'm intensely curious to find out what the various parameters are to this problem...
If their WiFi network was setup in a single subnet (I know, not really possible for an organization that large) the problem likely wouldn't be occurring. If every Access Point was on the same subnet the "B to C" transition probably wouldn't trigger the bug.
It seems like you just skimmed the article. The iPhone is trying to find the MAC addresses of IPs that don't exist on a given segment of the Duke network (the ARP flooding). It happens when the phone loses WiFi connectivity in one location and tries to reconnect in another location. When it connects to the new segment it shouldn't be flooding it with ARP requests for addresses that don't exist on that segment. This is an IP stack flaw, pure and simple. What other possible explanation is there for it?
Yep - that was the "ridiculously fast rate" bit I mentioned. I'd say 30,000 per second is ridiculously fast.
As for ARP'ing when it reconnects, that probably is the right thing to do (or flushing the arp cache of addresses on that segment when that interface goes down) - when connecting to a whole new network, it probably best to check the MAC addresses again, as wrong-MAC address hangs take ages to fix themselves. So yes, it should be ARP'ing and no, it shouldn't be flooding - 1 or 2 seconds between packets is usual.
Thanks for posting the results of all that research - nice one.
The writer you chastise is correct you are wrong in this particular argument. Your logic is like saying ... if lying down on the sidewalk with your head in the road is a problem because cars keep hitting you then it might be an issue with the cars. The writer simply stated they should be sure what is the problem first. Moving your head would be worth a try first ...
Sure they have identified the iPhones are involved but if as the writer correctly says, IF this is because of a network screw up they might be wise to trouble shoot before publicly stating it is the FAULT of the iPhones and thus feeding trolls with fodder to repeat and exaggerate and attempt to damage Apple's reputation.
Your example is bad, and its backwards. The cars/road is the network, the person is the iPhone entering the network. The person gets hit by car, or just causes the cars to stop, thus causing bottlenecks in the network. Who do you blame? The cars? No, the person.
But beyond that, why should Duke keep quiet? Isn't public disclosure the important thing? Or is it that you're supposed to make sure you don't look bad? If you were on the Duke campus with an iPhone, would you rather know that they were having issues with their network, or just think that the problem is your phone, so you could spend hours on end trying to figure out why the network keeps fading out? Also by making it public, you can find out if others have the same problem, and whether or not someone's got a solution or workaround for the problem.
Are you thrilled when your broadband goes out at home, you call up the local cable company and they're "No, the service is fine, must be you" and then it turns out, guess what, it was them, but they didn't want to say anything because they didn't understand the problem? Or feared that you would cancel?
Maybe the reasoning behind 'no one else reporting it' is just they're all thinking like you "Hey, the problem might be our network, so I don't want to look bad because my job might be on the line, so I'm going to stay mum and see if I can work something out myself".
Comments
I'm just impressed the little iPhone can generate 10Mbps of traffic!
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
First, its 10 megaBIT, not megaBYTE. 10 mbit isn't that much. Especially if there is a flaw in the iPhone's IP stack. I have had single devices on my network broadcast way more traffic than that when misbehaving. This is entirely within the realm of possibility.
Its statements like yours that cause people to accuse us of being blind Apple zealot fanboys. Please, lets be open minded. Apple doesn't do everything quite perfectly.
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
Duke's network probably could be configured better to handle misbehaving devices, but let's not place all of the blame on them. If I run over someone with my car, does that mean the person I hit is at fault?
Right, I'm sure that's why they're trying to call apple, just to thank them. Or maybe they should complain because, for some reason, the iPhone is crashing their network. Would there be a reason that 18000 students with laptops or other wifi devices all work fine, but throw a few iPhones into the mix, and all of a sudden its the network's fault? Its not that the phone's are asking for a bad router address, it must be because the other routers aren't responding, even though they don't even have that address.
Then again, maybe if the folks at Duke (or, hell, UNC) stopped patting themselves on the back and congratulating themselves on how great they are, and spent time actually working, they might find the problem.
And is anyone surprised that the communication has been 'one-way'?
First, its 10 megaBIT, not megaBYTE. 10 mbit isn't that much. Especially if there is a flaw in the iPhone's IP stack. I have had single devices on my network broadcast way more traffic than that when misbehaving. This is entirely within the realm of possibility.
Its statements like yours that cause people to accuse us of being blind Apple zealot fanboys. Please, lets be open minded. Apple doesn't do everything quite perfectly.
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
Duke's network probably could be configured better to handle misbehaving devices, but let's not place all of the blame on them. If I run over someone with my car, does that mean the person I hit is at fault?
Thank you!
If the explanation in the article is correct, which it seems to be, its the iPhone that is generating the traffic that is causing the problem. I'm an IT guy, and the explanation is perfectly plausible and credible. From their description, it truly looks like Apple made a mistake. And it should be fixable.
But then the question stands still, why aren't other people complaining about this? Wouldn't Apple's Campus wifi have seen this? Or how about any other wifi networks? I would think if the issue is simply the iPhone mucking up WiFi, that more and more people would be speaking up saying "Apple messed up".
You want us to not be so quick to lay the blame on Duke and let Apple off. So likewise, don't just eat up a single report, and write it off as Apple having made a mistake. At this point, i'd say its an unknown, with potential for both to be at fault.
I work in IT, though I'm not a network person, and I remember how our network folks were hell bent on segmenting our network into separate zones for students, labs, faculty and administrators, and our school is only ~2500 users total. Why would such a large institution such as Duke opt for a flat network setup?
Of course, it may be an iPhone with a wonky wi-fi card. I've seen bad ethernet cards flood the network, sometimes causing what the network folk call an "arp-storm". It could be that one or two bad iPhone wi-fi cards are wreaking havoc with Duke's flat setup.
I've been using my iPhone on our (segmented) network for 2 weeks, and haven't had a single problem (and our network folk are such that if anything causes a problem, they search and destroy immediately). The fact that other places aren't reporting the same problem places the blame closer to NC than to Cupertino. Unfortunately, too many higher-ed IT/network people come from the corporate world where, if it doesn't have a Microsoft logo you get the 2000 yard stare if you bring them a problem with a Mac. That's also the source of their knee-jerk "it has to be Apple's problem".
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
Or a poorly designed and implemented network that is allowing traffic looking for a "incorrect network" to continuously loop. I believe RIP without proper Poison Reverse could cause this.
I wonder what protocols and design they have? I can't find any info on the net anywhere.
It's got to be the network. A Mac address request is very small. It would take an iPhone Flashmob of about 200,000 people to generate 10MB of Mac address requests.
Come on guys, it's the network, not the iPhones. Otherwise this result would be worldwide.
Just another fruitless attack on the iPhone. Oh, they can be soooo jealous, can't they?
Because it can't be a problem with the iPhone OS's network stack. It has been known that OS software can contain bugs that could cause issues. Its happened in the past.
Duke's IT group should have been more cautious about staying the iphone has problems because in the end they might be the ones with egg on their face.
No, they shouldn't be more cautious. They already tracked down the cause: its iPhone traffic. They also know that its looking for a router that doesn't exist, and requesting continuously for that router (see, even if they are from Duke, they aren't completely clueless - but, really, we all know they're working there because they couldn't get jobs at the Univ. of Maryland).
From that perspective, they're completely correct. The iPhone is royally screwing up their network. Now, whether its because of issues with the iPhone itself, or its their network setup, is a different story.
The writer you chastise is correct you are wrong in this particular argument. Your logic is like saying ... if lying down on the sidewalk with your head in the road is a problem because cars keep hitting you then it might be an issue with the cars. The writer simply stated they should be sure what is the problem first. Moving your head would be worth a try first ...
Sure they have identified the iPhones are involved but if as the writer correctly says, IF this is because of a network screw up they might be wise to trouble shoot before publicly stating it is the FAULT of the iPhones and thus feeding trolls with fodder to repeat and exaggerate and attempt to damage Apple's reputation.
But then the question stands still, why aren't other people complaining about this? Wouldn't Apple's Campus wifi have seen this? Or how about any other wifi networks? I would think if the issue is simply the iPhone mucking up WiFi, that more and more people would be speaking up saying "Apple messed up".
There are several possibilities... Maybe Duke's network is too flat and should be segmented better. Maybe Duke is the only one saying anything. But even if both of those are the case, it doesn't excuse the behavior of the iPhone. No device should be flooding a network with ARP requests, period. Whether the network can handle it or not is not the issue here.
Apple is allowed to make a few little mistakes here and there, right? I'm sure they'll fix it. You guys are acting like there is no way in hell it could be a problem with the iPhone. Let's be a little more realistic.
The iPhone WiFi is fine, they're getting (presumably by DHCP) a router address that doesn't exist, and then looking for that router whenever they want to send traffic off the subnet.
And the netadmins haven't worked out yet where they're getting their router information from - if the network's that flat then the responsibility would seem to be with whoever's running a misconfigured DHCP server, andthe netadmins to track it down sharpish.
What's off is that other wifi connected devices getting a DHCP address on that net would work, and iPhones wouldn't.
A few things could cause that - other stuff might not actually work, they might have some DHCP strings that mean the duff DHCP server gets selected to serve them, or there could have been a change such that everything with an existing DHCP address lease retains it's (working) config, but new devices (like all the iPhones that just got bought) get the new (duff) information.
BTW, it's not an iPhone thing - any device looking for a router will keep ARPing for it until it turns up. It could be that the iPhones ARP at a ridiculously fast rate, or there's a lot of them - most IP networks have some spurious ARP traffic, but usually for non-existent hosts, rather than routers.
Cheers,
Martin.
Um, they explained the issue the article.
...
BTW, it's not an iPhone thing - any device looking for a router will keep ARPing for it until it turns up. It could be that the iPhones ARP at a ridiculously fast rate, or there's a lot of them - most IP networks have some spurious ARP traffic, but usually for non-existent hosts, rather than routers.
It seems like you just skimmed the article. The iPhone is trying to find the MAC addresses of IPs that don't exist on a given segment of the Duke network (the ARP flooding). It happens when the phone loses WiFi connectivity in one location and tries to reconnect in another location. When it connects to the new segment it shouldn't be flooding it with ARP requests for addresses that don't exist on that segment. This is an IP stack flaw, pure and simple. What other possible explanation is there for it?
The article also states that it is only two iPhones that are causing all of the problems. Sounds like they have really narrowed it down.
Quoting from the article: "On two occasions, one last Friday and one today, Monday 16 July, both users seemed to be behaving completely normally, yet both iPhones started flooding the net with ARP requests. In both cases, the user first successfully connected to the WLAN at one location, and then moved to another building, where the ARP flood began. 'It may have something to do with the iPhone losing connectivity and then trying to reconnect in a new location,' Miller says." This makes it pretty clear that the problem is with the iPhone. Not a lot of room for debate if you ask me.
Again, I suspect that the Duke network isn't set up to gracefully handle roaming clients, *and* there very well may be an issue with the iPhone stack, and the combination of the two is causing the situation.
1. It isn't just happening at Duke. Other networks are seeing it too; Duke is the only one that has gotten picked up by the media so far. (And, by the way, they didn't go to the media, Network World found the discussion of the problem in a blog, and came to them to ask to publish the story.) Most other locations are banning the range of iPhone MAC addresses to prevent them from bringing their networks down. (And just because you haven't heard about it doesn't mean it isn't happening elsewhere, BTW!)
2. It isn't happening with all iPhones. It is a strange set of circumstances that trigger the problem. A given phone has to have been at three locations with similar configurations but different IP subnets successively (first at location A, then B, then C, though the specific locations of A,B and C do vary). At location C the iPhone tries to find a router that existed at location A, and sends out 30 ARP requests to find that router EVERY MILLISECOND, so each iPhone is sending out roughly 30,000 ARP requests per second.
3. It also appears that the default settings on the iPhone may not trigger the problem, that the user has to have changed the WiFi configuration to some degree, though to what degree that is remains unclear.
4. The Duke network isn't "flat" as some have suggested. It appears to have been well organized and implemented, and this is (ironically) actually contributing to the iPhone's behavior.
5. No device should EVER send out 30,000 ARP requests for the same IP address per second, no matter what the circumstances of the network it is connected to, much less when the requested IP address isn't in the iPhone's current subnet.
6. The problem ticket has been escalated at Apple to try to find a solution.
It's a bug in the iPhone, and Apple will fix it.
These Tweedle-Duke and Tweedle-Ding-Dongs don't know their heads from their rear ends. In my day, you were a computer genius if you were the SYSOP of a BBS.
Enough of this iPHONE shenanigans... Get your books out, walk to and from your classes uphill both ways, and study.
iPhone tom-foolery... enough
I just spent the last hour researching this in the original forums where the problem is being discussed. Definitely an iPhone problem...
It's a bug in the iPhone, and Apple will fix it.
Keen, thanks for the update.
How is the Duke network setup exacerbating the issue? I'm intensely curious to find out what the various parameters are to this problem...
How is the Duke network setup exacerbating the issue? I'm intensely curious to find out what the various parameters are to this problem...
If their WiFi network was setup in a single subnet (I know, not really possible for an organization that large) the problem likely wouldn't be occurring. If every Access Point was on the same subnet the "B to C" transition probably wouldn't trigger the bug.
It seems like you just skimmed the article. The iPhone is trying to find the MAC addresses of IPs that don't exist on a given segment of the Duke network (the ARP flooding). It happens when the phone loses WiFi connectivity in one location and tries to reconnect in another location. When it connects to the new segment it shouldn't be flooding it with ARP requests for addresses that don't exist on that segment. This is an IP stack flaw, pure and simple. What other possible explanation is there for it?
Yep - that was the "ridiculously fast rate" bit I mentioned. I'd say 30,000 per second is ridiculously fast.
As for ARP'ing when it reconnects, that probably is the right thing to do (or flushing the arp cache of addresses on that segment when that interface goes down) - when connecting to a whole new network, it probably best to check the MAC addresses again, as wrong-MAC address hangs take ages to fix themselves. So yes, it should be ARP'ing and no, it shouldn't be flooding - 1 or 2 seconds between packets is usual.
Thanks for posting the results of all that research - nice one.
Cheers,
Martin.
The writer you chastise is correct you are wrong in this particular argument. Your logic is like saying ... if lying down on the sidewalk with your head in the road is a problem because cars keep hitting you then it might be an issue with the cars. The writer simply stated they should be sure what is the problem first. Moving your head would be worth a try first ...
Sure they have identified the iPhones are involved but if as the writer correctly says, IF this is because of a network screw up they might be wise to trouble shoot before publicly stating it is the FAULT of the iPhones and thus feeding trolls with fodder to repeat and exaggerate and attempt to damage Apple's reputation.
Your example is bad, and its backwards. The cars/road is the network, the person is the iPhone entering the network. The person gets hit by car, or just causes the cars to stop, thus causing bottlenecks in the network. Who do you blame? The cars? No, the person.
But beyond that, why should Duke keep quiet? Isn't public disclosure the important thing? Or is it that you're supposed to make sure you don't look bad? If you were on the Duke campus with an iPhone, would you rather know that they were having issues with their network, or just think that the problem is your phone, so you could spend hours on end trying to figure out why the network keeps fading out? Also by making it public, you can find out if others have the same problem, and whether or not someone's got a solution or workaround for the problem.
Are you thrilled when your broadband goes out at home, you call up the local cable company and they're "No, the service is fine, must be you" and then it turns out, guess what, it was them, but they didn't want to say anything because they didn't understand the problem? Or feared that you would cancel?
Maybe the reasoning behind 'no one else reporting it' is just they're all thinking like you "Hey, the problem might be our network, so I don't want to look bad because my job might be on the line, so I'm going to stay mum and see if I can work something out myself".