Down-thread of this comment, people have already discussed numerous issues with the assumption that DHCP leases are stable when not in use (such as that servers often choose to allocate out of an artificially small pool of addresses, and ping old addresses to determine if they are in use before simply reclaiming and reassigning them).
Like I said, if you're uncomfortable with the trade-off, avoid Apple devices. Personally, I only see the number of devices like the iPad/iPhone increasing, and I'm relatively confident that your normal user doesn't give a damn about any of this. They want the device to work when they turn it on.
I'd also argue that any DHCP server that applies that policy of artificially limiting the IP pool by re-issuing non-expired leases is an asinine implementation.
I know next to nothing about iOS as it relates to Darwin, but if the DHCP stack is part of Darwin, it'll be OSS, which means someone could patch the DHCP client to not exhibit this behavior.
How many people do you think would install that patch?
* Resolves potential IP conflicts when recovering from sleep
* Adds 10s to network availability in most situations
Nobody. For the record I agree with you, I wasn't defending saurik just pointing out that your resolution was inadequate as he is overly invested at this point.
> They want the device to work when they turn it on.
If there is a collision, then this doesn't 'just work' when the user turns it on. Just sayin'. From the user's perspective the device should never fail, in any situation, for any reason... ever. Users don't care about trade-offs because they don't want to trade anything off, they want it all, 5 minutes ago.
> If there is a collision, then this doesn't 'just work' when the user turns it on.
No, it just potentially kicks off another user. I've never been unable to acquire an IP because of this practice, I've just seen other people's wireless mysteriously give up the ghost when I connect with my iPhone or Mac. I would prefer to have the aggressive device, personally.
You're falsely attributing this behavior to your iPhone/Mac. Keep a couple of things in mind:
* If you have a valid lease, there should be no conflicting IP addresses on the network
* Even if you do have a conflicting IP address, that conflict only exists until the DHCP server issues you a new one (iOS immediately performs the DHCP request after sniffing)
IP conflicts are not voodoo magic. Once the conflicting machine gets a new IP address, everything returns to normal. The network events shown in the article show that this occurs in about 1s; between the time that the interface comes up, 0.3s, and the time the interface is active, 1.3s. If this were a full negotiation, it would take around 5s.
The key thing to remember is that this shouldn't happen at all on healthy networks. So, if anyone chooses to remain opposed to this, they're saying that waiting 10s every time you wake a portable device from sleep and want to use the network connection is a worthwhile tradeoff to accommodate DHCP servers that don't respect leases and switches that can't adequately resolve an ARP entry conflict in a timely manner.
I've said it about ten times in this discussion already, but I'll keep the ten seconds (times 15-20 sleep/wake events per day) and buy decent network equipment.
> What happens on a technical level when every device behaves like that?
We start putting battery backup in routers so they won't drop their DHCP tables? This isn't asshole mode, it's "assume the network is functioning properly and hasn't been reset" mode. In the world of portable devices, it's important to look at where we waste time and compensating for errors is a frequent culprit.
