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0 pointsshinratdr14y ago0 comments

> 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.

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4 comments · 2 top-level

derleth14y ago· 2 in thread

> I would prefer to have the aggressive device, personally.

So, by basic game theory, everyone implements 'asshole mode' in their devices. What happens on a technical level when every device behaves like that?

nicolasp14y ago

Router vendors start saving DHCP lease tables to stable storage and the issue is fixed?

shinratdrOP14y ago

> 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.

bradleyland14y ago

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.

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