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Rapid DHCP: Or, how do Macs get on the network so fast?

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Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#181

Post by [deleted] »

zb wrote: post #167
saurik wrote: post #15

> This network recognition technique allows the Mac to very rapidly discover if it is connected to a known network. If the network is recognized (and presumably if the Mac knows that the DHCP lease is still active), it immediately and presumptuously configures its IP interface with the address it knows is good for this network. Ok, seriously? That isn't a bug in an implementation somewhere, but in fact a feature that…

> Ok, seriously? That isn't a bug in an implementation somewhere, No. > but in fact a feature that Apple actually is proud of? Not just Apple, but I imagine also Microsoft and Sun. They were so proud of it that they wrote a standards-track RFC for it: http://www.ietf.org/rfc/rfc4436.txt And yes, they were aware of this issue: One case where DNAv4 does increase the likelihood of an address conflict is when: o a DHCP s…

[deleted]

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#182

Post by shinratdr »

jarek wrote: post #179
shinratdr wrote: post #178

Earlier quoted context omitted.

Except I drink hundreds and hundreds of cups of coffee a day. When it takes 10 seconds every time to determine who's coffee it is, we need to come up with a new solution. Yeah this analogy blows as well. What it comes down to is old world technology spends a ton of time on error correction like this and it's an easy place to increase efficiency & speed for portable devices. It's going to keep happening, get used to i…

Except it doesn't take 10 seconds. The time between the Galaxy Tab's proper DHCP discover and DHCP ACK was 0.653 seconds. You might notice a difference between that and the Mac's 0.031 seconds to DHCP-free link up if you blink fast. This conversation makes me want to block Apple devices from any and all devices I control. Because hey, such anti-social network behaviour is going to keep happening. Because it's not a b…

> Except it doesn't take 10 seconds. The time between the Galaxy Tab's proper DHCP discover and DHCP ACK was 0.653 seconds. You might notice a difference between that and the Mac's 0.031 seconds to DHCP-free link up if you blink fast.

I unlock my phone and launch MobileSafari in less than a second, so it matters.

> This conversation makes me want to block Apple devices from any and all devices I control.

So do it then. If it actually enhances your experience, why compromise for users that don't matter to you? That's my point. You don't need to enforce network neutrality on your own AP.

> Because hey, such anti-social network behaviour is going to keep happening.

As long as router manufacturers keep being cheap and expiring DHCP leases after a reset, yes it will.

> Because it's not a big deal. Because you're worth it.

Damn straight.

> Good thing the network layer doesn't support such, uh, experience-enhacing features.

True, they should work on that. While their at it, add the ability to save DHCP tables before a reset and solve the actual problem here.

Even for new network discovery, 10 seconds is unacceptable on a portable device. Reconnects should be as quick as possible, no exceptions.

Sorry if you are offended that companies are actually working on improving this instead of insisting that it's good enough as it is.

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#183

Post by shinratdr »

jarek wrote: post #122
shinratdr wrote: post #120

Earlier quoted context omitted.

It's really not. There is no real world comparable act, frankly. It is what it is, and what it is is not a big deal.

I cannot emphasize enough how much I disagree with the idea that potentially inconveniencing other network users for a small gain of your own is not a big deal.

Good for you. It's still not a big deal and you can't "outrage" that away.

It's not a small gain, for the record. And the only users you are inconveniencing are ones that are malfunctioning. If everything is working correctly and the AP hasn't been reset, this causes no inconvenience to anyone and results in a clear direct benefit for the user.

You figure a community of developers would possibly give a shit about what matters to the UX, I guess not. You do know that the "U" stands for user, right?

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#184

Post by sid0 »

shinratdr wrote: post #176
sid0 wrote: post #136

Earlier quoted context omitted.

I agree with Kant here: when deciding whether an action is right, one should consider what would happen if everyone started doing it. Also, you're a dick. Congratulations.

I'm a dick for buying products that work best for me and not other users or developers? Ok... I thought the Hacker News community was supposed to have a modicum of maturity?

You're a dick for buying products that actively negatively affect other users and that would lead to chaos if everyone bought them, yes.

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#186

Post by tintin »

flogic wrote: post #79

Rather than asking why the mac is so fast, the correct question is "why the hell is dhcpcd so slow?". There's a full second before it does anything.

The client is waiting a full second to give all DHCP servers the ability to answer the request for an IP address offer.

Then the client will choose the best offer and will tell that DHCP server it took the offer.

I think after that the DHCP server is letting all other DHCP servers know the current status of available IP addresses. Maybe that will also take some time (with a lot of waiting, time-outs and stuff).

But then the question remains why should it take more than 2 seconds?

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#187

Post by jarek »

shinratdr wrote: post #182
jarek wrote: post #179

Earlier quoted context omitted.

Except it doesn't take 10 seconds. The time between the Galaxy Tab's proper DHCP discover and DHCP ACK was 0.653 seconds. You might notice a difference between that and the Mac's 0.031 seconds to DHCP-free link up if you blink fast. This conversation makes me want to block Apple devices from any and all devices I control. Because hey, such anti-social network behaviour is going to keep happening. Because it's not a b…

> Except it doesn't take 10 seconds. The time between the Galaxy Tab's proper DHCP discover and DHCP ACK was 0.653 seconds. You might notice a difference between that and the Mac's 0.031 seconds to DHCP-free link up if you blink fast. I unlock my phone and launch MobileSafari in less than a second, so it matters. > This conversation makes me want to block Apple devices from any and all devices I control. So do it the…

Thanks for your reply.

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#188

Post by shinratdr »

sid0 wrote: post #184
shinratdr wrote: post #176

Earlier quoted context omitted.

I'm a dick for buying products that work best for me and not other users or developers? Ok... I thought the Hacker News community was supposed to have a modicum of maturity?

You're a dick for buying products that actively negatively affect other users and that would lead to chaos if everyone bought them, yes.

It would lead to chaos if every device retained the IP it used on that AP previously? Yeah that sounds like hell, imagine the horror.

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#189

Post by shinratdr »

bradleyland wrote: post #180
shinratdr wrote: post #87

Earlier quoted context omitted.

> Like I said, if you're uncomfortable with the trade-off, avoid Apple devices. Something tells me Saurik is a tad more invested at this point, it's not really as simple as "avoiding Apple devices" when you are the dev of Cydia.

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.

Re: Rapid DHCP: Or, how do Macs get on the network so fast?

#190

Post by philjr »

bronson wrote: post #174
jarek wrote: post #77

Earlier quoted context omitted.

Well, sure, but the problem is that the Apple device user doesn't suffer from the negative consequences of the non-standard action. Other users do. Of course people are going to like devices that allow them to cut in line if there is a little bit of space.

Non-standard action? It's standardized by RFC 4436!

Not all RFCs are standards. See http://tools.ietf.org/html/rfc1796 entitled "Not all RFCs are standards" :)
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