2011/12/28 Masataka Ohta <mo...@necom830.hpcl.titech.ac.jp> > valdis.kletni...@vt.edu wrote: >
> <SNIP> > > >> In this case, the following statement in RFC1883: > >>> If the minimum time for rebooting the node is known (often more than > >>> 6 seconds), > >> is the wrong assumption which made RA annoying. > > > > Oddly enough, a lot of us are running on networks where assuming this > about end > > user gear is perfectly reasonable. > > That is because, as I wrote already in the previous mail, > > > Network configuration was mostly stationary > > For example, IPv6 might work well, if most of your end users > are not moving rapidly between small mobile cells. > > However, assuming you change the cells every 100m in average > and you are moving at 100km/h, you must change the cells every > 3.6 seconds in average, which means you must be able to change > the cells frequently, which means each cell change take a lot > less than 3.6 seconds. > To me, that sounds like an argument in favor of SLAAC. SLAAC is noticeably faster in my experience than DHCP (v4 or v6). Also, RAs can be sent in the ms range - for environments that expect that type of attachment-point-churn ... Also: Isn't 100m an arbitrarily tight range for a cel tower? And for cellular, isn't the real churn happening more at the Layer2 side ... no L3/IPv6/IPv4 interaction? > > We haven't seen many consumer-grade > > Windows, Macs, or Linux boxes that are able to reboot in much under 6 > seconds. > > IPv6 is wrongly architected, not because it assumes nodes are > able to reboot in much under 6 seconds, but because it assumes > new configurations necessary only at boot time. > Boot time, or anytime a change in network attachment point is detected ... is that not sufficient? > Yes, I know you can do it with careful tuning and throwing SSDs and other > > hardware at it - doesn't mean it's common. > > Obviously, the IPv6 committee and you are assuming computers > of immobile main frame computers or, at least, immobile > workstations. > > However, in the real world, commonly available mobile phones > are IP capable computers which wake up from dormant state > within a second and needs handover often within a second. > Again, if we are arguing about simple speed of address attainment - SLAAC wins. > Masataka Ohta > /TJ
