Re: Question about IPAM tools for v6
On 3 Feb 2014, at 11:17, Nick Hilliard n...@foobar.org wrote: On 03/02/2014 11:11, Sam Wilson wrote: Let me de-lurk and make the obvious point that using standard Ethernet addressing would limit the number of nodes on a single link to 2^47, and that would require every unicast address assigned to every possible vendor. Using just the Locally Administered addresses would limit you to 2^46. it bothers me that I can't find any switch with 2^46 ports. Damned vendors. The back of my envelope says that with my vendor of choice and a 4-deep tree (7-hop old-style STP limit) of 384-port switches I can't get more than about 2^34 edge ports. Very disappointing. That would need approximately 57 million routers, though, and 170 GW of electrical power, not counting the cooling requirements. -- Sam Wilson Communications Infrastructure Section, IT Infrastructure Information Services, The University of Edinburgh Edinburgh, Scotland, UK The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
Re: Question about IPAM tools for v6
On 3 Feb 2014, at 11:58, Tim Chown t...@ecs.soton.ac.uk wrote: On 3 Feb 2014, at 11:32, Sam Wilson sam.wil...@ed.ac.uk wrote: On 3 Feb 2014, at 11:17, Nick Hilliard n...@foobar.org wrote: On 03/02/2014 11:11, Sam Wilson wrote: Let me de-lurk and make the obvious point that using standard Ethernet addressing would limit the number of nodes on a single link to 2^47, and that would require every unicast address assigned to every possible vendor. Using just the Locally Administered addresses would limit you to 2^46. it bothers me that I can't find any switch with 2^46 ports. Damned vendors. The back of my envelope says that with my vendor of choice and a 4-deep tree (7-hop old-style STP limit) of 384-port switches I can't get more than about 2^34 edge ports. Very disappointing. That would need approximately 57 million routers, though, and 170 GW of electrical power, not counting the cooling requirements. That's a lot of hamsters. Turns out it's more hamsters than we have in the UK. http://www.gridwatch.templar.co.uk/ Sam -- Sam Wilson Communications Infrastructure Section, IT Infrastructure Information Services, The University of Edinburgh Edinburgh, Scotland, UK The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
Re: Over-utilisation of v6 neighbour slots
On 22 Oct 2013, at 06:03, Eric Vyncke (evyncke) wrote: But, the rapid rate of new RFC 4941 addresses for iOS has another impact because network devices cannot anymore limit the number of IPv6 addresses per MAC address in order to prevent a local DoS. So, either you disable SLAAC and rely on stateful DHCPv6 (but then Android is not happy) or use aggressive time to clean the ND cache... ... with the attendant difficulty in tracing systems that might be doing Bad Things. We have a mixture of Sup2Ts and Sup720s and we don't (yet) have v6 enabled on most of them. It's stuff like this that makes me think it's *still* not time to offer a general v6 service. Sam -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
