Re: Can Peer-to-Peer Model Be Launched in AppStore?
Re: Can Peer-to-Peer Model Be Launched in AppStore?
- Subject: Re: Can Peer-to-Peer Model Be Launched in AppStore?
- From: Bing Li <email@hidden>
- Date: Tue, 23 Aug 2011 01:26:30 +0800
Dear Wayne,
Thanks so much for your email!
I don't understand your opinions well. Jens said 3G did not allow incoming connections. So I think P2P does not work in such an environment. I have to try to use app notifications. The major reason I use P2P is to get a lower load on the server and users can get pushed data.
For iPad/iPhone within a NAT, I will ask the device to connect the server outside the NAT firstly. So a connection can be established. Pushing can be done without the block of NAT.
Do you think my solution works?
Best,
Bing
On 2011-8-23, at 上午12:48, Wayne J wrote:
> The issue is more general than 3g vs wifi. There are several issues involved here neither of which or 3g specific.
>
> There are generally firewalls between the Internet and intranets. For security reasons, incoming connections are not allows for non-server machines.
>
> It is very common for intranets to use non-routable IP addresses internally and connect to the Internet via NAT (network address translation.) This servers tow purposes. It allows an intranet to share IP addresses with many machines. There is also a secondary benefit. Because of the way NAT works, unless you explicitly setup rules for incoming connections they cannot be routed. The router implementing the NAT is directly addressable from the Internet but machine inside the Intranet are not addressable from the Internet.
>
> You want this for you iPhone and your iPad.
>
> * It makes it harder to exploit your phone from the Internet. As is it you (the user) must connect to some Web service in order for exploits to be taken advantage of.
>
> * You don't have random computers trying to connect to your device all the time. There are many people all over the world who are constantly running scripts that scan blocks of IP addresses for known exploits. If you device where directly accessible you would end up paying for the data sent to your phone during these attempts. The amount of data is small but the attempts are fairly constant.
>
> * Your device cannot be specifically targeted with a DOS attack. This will be even more important as we move into the new wireless technologies. The new technologies are moving towards some form of VOIP for calling. A DOS attack could prevent you from even making a call (say to 911.)
>
> I don't believe there are any technical reason why you could not setup a 3g network where phones could communicate in P2P mode or even run some sort of server.
>
>
> Wayne
>
>
> On Aug 21, 2011, at 11:19 PM, Bing Li wrote:
>
>> Dear Jens,
>>
>> I just know about the constrains on 3G. Thanks so much for your replies!
>>
>> I will implement my system on WiFi first. Because of LAN, the multicast is
>> not so flexible as on a true P2P. The load on my server must be high.
>>
>> On 3G, the iPad must always establish the connection and send requests
>> before getting data from other nodes, right? That is not my expectation. I
>> will try app notifications instead.
>>
>> Thanks again!
>>
>> Best,
>> Bing
>>
>>
>> On Mon, Aug 22, 2011 at 1:49 PM, Jens Alfke <email@hidden> wrote:
>>
>>>
>>> On Aug 21, 2011, at 10:32 PM, Bing Li wrote:
>>>
>>> According to your email, P2P is not available on 3G?
>>>
>>>
>>> A device can’t receive an incoming TCP connection over 3G. That’s part of
>>> the way the carriers run IP over their cell networks, not anything mandated
>>> by Apple.
>>>
>>> (All the incoming signaling handled by iOS, like phone calls, SMS, and app
>>> notifications, runs directly over GSM without using IP. 3rd party apps
>>> definitely don’t have access to that low-level functionality; the carriers
>>> are pretty nervous about unauthorized use of it.)
>>>
>>> If so, P2P based applications cannot be launched in AppStore?
>>>
>>>
>>> No, it doesn’t rule out P2P, it’s just that the device will have to be the
>>> one making the connection.
>>>
>>> For example, it’s possible to run a BitTorrent node without accepting
>>> incoming connections; in practice, the other nodes will think you’re
>>> leeching and probably won’t send you much data, but that’s a matter of
>>> configuration, not part of the protocol. It all depends on how your protocol
>>> works.
>>>
>>> Without 3G's support, how can a P2P system run in a wireless environment?
>>>
>>>
>>> WiFi? Bluetooth?
>>>
>>>
>>
>>> —Jens
>>>
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