Can Apps Really Damage a Cellular Network? 309
schnell writes "In FCC filings earlier this year, T-Mobile described how the behavior of one Android IM app nearly brought their cellular data network to a breakdown in one city. Even more interesting, the US carrier describes how just the 300,000 unlocked iPhones on their network caused massive spikes in data usage. T-Mobile is using these anecdotes as evidence that mobile carriers should be able to retain control over the applications and devices on their network to ensure quality of service for all users. Do they have a point?"
what? (Score:0, Informative)
Re:what? (Score:1, Informative)
Re:what? (Score:3, Informative)
Re:No. (Score:2, Informative)
Re:T-Mobile has exclusivity of iPhone in Germany (Score:3, Informative)
Simple: over there they're probably actually having to, yknow, compete. Over here they just bitch to the government about how its just so HAAAAAAAARD and get regulations passed to let them get off with doing less work.
Re:No. (Score:5, Informative)
That's not true.
UMTS signalling traffic is actually a big worry too.
Setting up and tearing down radio resource connections all the time has a burden on the network. Mobile applications, with their diverse update patterns (e.g. polling every 30 minutes (email apps), or minute or even few seconds (e.g. IM apps)), can make it difficult for carriers to set up their RRC inactivity timers and various other settings in a way that minimises signalling load on the network.
Re:what? (Score:5, Informative)
While EDGE is counted under the 3G banner, it's really not 3G at all.
EDGE is upgraded 2.5G (GSM/GPRS), speeds are not even close to basic HSPA.
There's a theoretical max of 473.6kbps for EDGE, 14mbps with HSPA. So the "traffic spikes" claimed by T-Mobile are laughable. If you're network can't handle 1/28th of it's capacity then there's something seriously wrong with it.
Re:No. (Score:5, Informative)
Actually, yes, it is possible.
You simply flood the network with control messages. That will effectively DoS the tower. What kind of control messages? Well, sending an SMS is a control message. Setting up and tearing down data and voice connections are other control messages, and all are done on behalf of apps.
Supposedly, one of the major reasons AT&T is having issues with the iPhone is because the iPhone actually does this, a lot. Control channel bandwidth is limited and normally, you don't have much going across it (because it's just call setup/teardown and the like). But with the meteoric rise of SMS and data usage, the control channel actually is in somewhat of a bandwidth crunch.
Europe and Asia have no problems with iPhones as they've gone to a dynamic bandwidth control channels because of the popularity of SMS. North America until recently didn't need to. So now control channels are somewhat packed with text messages, and you introduce the iPhone with its aggressive power management that tears down data connections ASAP. So a data channel might be established and torn down to view one web page or whenever an app requests data. Most phones prior to this created a data channel and hung onto it until it idled for a long period of time (after all, you're billed by the packet, so keeping the data channel open costs nothing, and it means it's always ready when you need it so you don't have to wait to establish the data channel again and again).
I can see a few apps that constantly abuse this which can easily take down a network. Setting up/taking down a voice call, setting up/taking down the data connection, do it fast enough and you can really clog up the tower. Enough people do this and the tower can be put out of service because it's stuck establishing and taking down connections so fast that no one else can get in.
Raw bandwidth wise though, you're not likely to do anything other than slow down due to congestion if the tower's uplink gets saturated.
In fact, that's what the IM client did - it established and tore down connections very quickly. A phone with aggressive power management (required on Android) would basically be spewing out control messages all day. This can be made more painful if the carrier makes notes in a database for billing purposes.
Not Data Usage but Connection Overhead (Score:5, Informative)
I recall reading somewhere that some European carriers use a different methodology that doesn't create such a bottleneck when these connections are opened and closed. So it seems that once again, the US cell carriers are trying to blame the users of their network for causing problems that would (could, and should) be fixed by upgrading the infrastructure. Cell providers make way too much money to complain about not being able to upgrade their networks.
Re:No. (Score:5, Informative)
"T-Mobile network services was temporarily degraded recently when an independent application developer released an Android-based instant messaging application that was designed to refresh its network connection with substantial frequency,..."
Lots of comments chiming in on overselling bandwidth, but as you've noted, this has nothing to do with bandwidth. Its an infrastructure problem, and one that is slightly out of their control. They noted with this one app alone, network utilization increased 1200% per device. Its a signaling issue they didn't anticipate.
Re:My only thought when reading the summary ... (Score:4, Informative)
remember, the issue they were complaining about was protocol, not bandwidth.
the problem they're having would be the same as allowing somebody to attach an FPGA with an ethernet jack to your CAT-6500. as much as you want to limit the port to only allow certain communication: there's nothing stopping the node from abusing the protocol.
the major difference here is that: the GSM stack assumes you trust your Mobile Stations (MS) because when it was written: telco's had full control over them. TCP/IP has no such restrictions (though I'm sure if you look at the standard long enough you'll find that you can send a physical signal to them in a particular way they will respond in a fashion you don't expect.) the analogy here would be that a GSM BTS acts much like a hub (almost exactly) and when one user keeps storming it with packets, nobody else get's a chance to talk.
personally: I don't see this as either a telco OR a user issue: it's a protocol issue. we need to take another look at the wireless communication protocol, and find another way of allowing untrusted users their fair access to the medium. (in this case, a pretty narrow band of wireless spectrum). telco's need to push standard-makers/suppliers for something they can sell these days: not some old outdated protocol that allows things like this to happen.
unfortunately: Air IS like a hub: only one person can talk on it at a time. so it'll be a hard fix.
Re:ulterior motives (Score:3, Informative)
also: when you try to issue 1GB in control messages a month, and only use 1GB in bandwidth with that 1GB in control. you can't charge for bits that needed to get transfered due to their network errors, or for the ICMP keep-alives the towers send to the phones. they're complaining that they can't charge for the control: because newer open devices are capable of more then they had planned for in overhead.
Re:No. (Score:1, Informative)
I work in delivery of 4g services and I can tell you that we have dealt specifically with one customer's network that has been pounded by rogue devices, devices presumably with some form of malware attempting thousands of authentications per second.
This is bad for everyone, screw up the phone, screw up the firmware, screw anything up for more than a few users, and the speed and power at which these things can run will bring a network to trash.
Re:No. (Score:4, Informative)
It's not TCP/IP that tears down the connection. That is a physical layer function, regardless of if the call came from the application layer. TCP/IP does not have influence over the physical layer.
Re:T-Mobile has exclusivity of iPhone in Germany (Score:3, Informative)
where one telco covers Europe with "decent coverage/speed" for $250,000, one in north america covers one major city for the same budget.
I'm fascinated by how somebody with such an obviously negative amount of geographic and financial clue made it to a +4 insightful.
DO have have any idea how a network works? (Score:3, Informative)
Seriously, what he hell are you talking about?
If your battery went dead, your handset would not perform a detach. The network would assume you are still connect but went into a building or something and would save your slot. For a set amount of time. I dont feel like looking into the core spec to see what that is, but we do test for that sort of thing when the phone goes through PTCRB or GCF certification.
In fact, EVERY SINGLE phone sold in the US has gone though PTCRB certification. There are literally thousands of protocol and rf layer test cases covering GSM/GPRS/EDGE and UMTS.
Nearly all test cases are CAT A, so you MUST pass them.
If an application has access to the stack, it certainly has the power to bring down tower. THIS IS WHY WE TEST PHONES!
Re:I am so tired of this argument (Score:3, Informative)
They own the network
Actually, they don't. A network consists of a number of endpoints and a number of interconnects. Most of the endpoints in a cellular network are client devices. They don't own these. The interconnects, in the case of a wireless network, are spectrum allocations. They don't own these, they rent them from the people (mediated by the government, in the form of the FCC in the USA), on the condition that they will use the spectrum in a way that benefits society (although some of this benefit comes from handing over a large pile of money to be allowed to use it). They do own a lot of the towers, although they rent a lot of the others.
My point is that their ownership rights are only truly applicable at the places where the bridging point where the mobile devices connect to the wired infrastructure. Beyond that, they have certain tenancy rights to the airspace - they can restrict what transmits within that spectrum, but only within the rules laid down by the FCC and only until their license for that spectrum is renewed. They have no rights at all on the client, any more your ISP has rights on your computer.
Re:What is so different in the EU, then? (Score:3, Informative)
> and enough rooted Androids with an ingenious Taliban created app that it
> would seem they would have enough easily accessible tools to carry out an
> effective paralyzing terror attack in say D.C.?
You don't need rooted Android phones for this. Any number of EV boards have been on the market for a few hundred dollars for years which could do this.
The only reason the terrorists haven't done this yet is that they are still trying to figure out how to get their toenail clippers and bottled water on the airliner for the trip to Washington.
Re:History (Score:1, Informative)
The story isn't quite like you seem.
AT&T was granted a monopoly by the government and the phone companies at the time for the purposes of promoting phone use. Now in the context of today, the concept of creating a monopoly to promote use may sound counterintuitive, but in the 20's, it made a lot of sense. Phone companies back then each had their own lines, and no phone companies could interconnect with another phone company's customers. You had streets that had nothing but wiring overhead as a result. Creating the monopoly allowed the business to grow. You could argue that the monopoly was kept for too long, but not that the monopoly when it was created was not useful.
As to the breakup, AT&T itself sued the government to allow itself to be broken up, because they themselves realized that the monopoly was not beneficial anymore. The conditions that caused competition from being efficient were no longer present (operators were being replaced by computers, the connectivity was largely standardized etc...).
As to the Carterphone lawsuit, the regulatory decision was not as you state, but that the FCC allowed other devices to attach to the AT&T network as long as they did no harm. Since the Carterphone did not directly connect to the AT&T network, it was allowed. This decision occurred long before the AT&T breakup. Oddly enough, with the breakup of AT&T, the conditions to force that requirement were no longer present, and phone companies are now free to prevent 3rd party device connections. Remember that a monopoly, while not illegal, cannot prevent others from entering the market. Now that there is no monopoly in the phone market (there never was one in telecommunications in general), a company can take actions that prevent others from getting into THEIR market.
This little facet of anti trust law is largely misunderstood, but that was the reason why there was actually two trials against MS. The first one to determine if MS was a monopoly, and the second one to determine if they used that monopoly to keep others out of the market. The second trial required MS to be declared a monopoly to go forward.