Re: SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
[Catching up on email] Benedikt, Note that https://tools.ietf.org/html/draft-ietf-6man-rs-refresh-00 is an attempt at addressing refresh without a multicast RA every 3 seconds, by only having the host do this refresh when it knows that the router doesn't default to multicasting solicited RAs. The key use case are hosts that sleep on a schedule i.e. that do not wake for any packets, but yet need to be able to quickly get connectivity when they do wake up. Whether RS refresh is useful vs. harmful for devices that wake up for packets is a source of discussion in the 6MAN WG. Regards, Erik On 6/13/15 10:25 AM, Benedikt Stockebrand wrote: Hi Lorenzo and list, Lorenzo Colitti lore...@google.com writes: On Thu, Jun 11, 2015 at 6:56 PM, Benedikt Stockebrand b...@stepladder-it.com wrote: they should at least send an RS when they wake up and ensure their configuration is still up to date. That sounds like a bad idea. If devices send an RS every time the user turns the screen on, and the router responds with a multicast RA, any medium-size network or larger will have multicast RAs flying around every 3 seconds and killing everyone's battery. not quite; as Eric pointed out, RAs may be sent unicast. While this was originally intended for underlying NBMA link layers, it does make kind of sense in this context, too. The downside with this however is that it makes monitoring for rogue routers more difficult again (using tools like ramond) at least in switched networks. But aside from that, my wording was imprecise. Make that send an RS when they wake up and they determine they have been offline long enough, for long enough being somewhat in the order of such that the router lifetime expired or similar. Figuring out the exact details is left as an excercise to the so inclined reader:-) Cheers, Benedikt
Re: SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
Hi Lorenzo and list, Lorenzo Colitti lore...@google.com writes: On Thu, Jun 11, 2015 at 6:56 PM, Benedikt Stockebrand b...@stepladder-it.com wrote: they should at least send an RS when they wake up and ensure their configuration is still up to date. That sounds like a bad idea. If devices send an RS every time the user turns the screen on, and the router responds with a multicast RA, any medium-size network or larger will have multicast RAs flying around every 3 seconds and killing everyone's battery. not quite; as Eric pointed out, RAs may be sent unicast. While this was originally intended for underlying NBMA link layers, it does make kind of sense in this context, too. The downside with this however is that it makes monitoring for rogue routers more difficult again (using tools like ramond) at least in switched networks. But aside from that, my wording was imprecise. Make that send an RS when they wake up and they determine they have been offline long enough, for long enough being somewhat in the order of such that the router lifetime expired or similar. Figuring out the exact details is left as an excercise to the so inclined reader:-) Cheers, Benedikt -- Benedikt Stockebrand, Stepladder IT Training+Consulting Dipl.-Inform. http://www.stepladder-it.com/ Business Grade IPv6 --- Consulting, Training, Projects BIVBlog---Benedikt's IT Video Blog: http://www.stepladder-it.com/bivblog/
Re: SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
Hi folks, I can't give you a decisive reference for where it's defined, but the default maximum interval is 600 seconds and the minimum interval is one third of that (200 seconds, not 180). The 1800s value may be a misinterpretation of the router lifetime field in the RAs, which has a default value of 1800. And yes, you can tweak these values at least on the implementations I tested about ten years ago. As far as tweaking these values to deal with some sleepy devices is concerned: I'd personally prefer to consider these devices broken; they should at least send an RS when they wake up and ensure their configuration is still up to date. Cheers, Benedikt -- Benedikt Stockebrand, Stepladder IT Training+Consulting Dipl.-Inform. http://www.stepladder-it.com/ Business Grade IPv6 --- Consulting, Training, Projects BIVBlog---Benedikt's IT Video Blog: http://www.stepladder-it.com/bivblog/
Re: SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
Hi, On Thu, Jun 11, 2015 at 09:56:45AM +, Benedikt Stockebrand wrote: As far as tweaking these values to deal with some sleepy devices is concerned: I'd personally prefer to consider these devices broken; they should at least send an RS when they wake up and ensure their configuration is still up to date. What I thought exactly. -is
Re: SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
Please read some IETF draft related to NDP/multicast/WiFi issues (Lorenzo is very active there). Multicast RA are not really needed anyway, some 'high market' (see my email address) AP have dozens of tricks to reply to RS with a UNIcast RA, and trying to reduce the amount of NDP mcast. If you want to measure by yourself: https://github.com/evyncke/mcast6 which will display basic summary of all your mcast IPv6 traffic. And bear in mind that every WiFi mcast frame wakes up ALL your WiFi device and is sent at the lowest rate (wasting bandwidth) ;-) On 10/06/15 02:20, erik.tarald...@telenor.com erik.tarald...@telenor.com wrote: I see that. I don’t think the problem is confined to Samsung or that it can be completed solved in isolation from fixing wireless AP router behaviour. At the edge of the WiFi network I also see the IPv6 connectivity dropping while IPv4 stays up. I’ve a ZyXEL home router that sends periodic RAs every 15 seconds and a Huawei home router that sends them every 1800 seconds. Any opinions on what a sane default value for what the RA interval should be? I have not conserned myself with that interval before, but I see that the residential devices we ship are on a very low interval. -- Erik Taraldsen
SV: Samsung phones block WiFi IPv6 when sleeping, delayed notifications
I see that. I don’t think the problem is confined to Samsung or that it can be completed solved in isolation from fixing wireless AP router behaviour. At the edge of the WiFi network I also see the IPv6 connectivity dropping while IPv4 stays up. I’ve a ZyXEL home router that sends periodic RAs every 15 seconds and a Huawei home router that sends them every 1800 seconds. Any opinions on what a sane default value for what the RA interval should be? I have not conserned myself with that interval before, but I see that the residential devices we ship are on a very low interval. -- Erik Taraldsen
