We have had IPv6 enabled on our wireless since 2008. This won’t help with exceeding ARP/Neighbor table sizes but changing the lifetime of IPv6 neighbor entries can reduce CPU issues on 6500s.
ipv6 nd reachable-time 900000 ipv6 nd ns-interval 5000 ipv6 nd router-preference High ipv6 nd ra interval msec 500 > On Sep 9, 2016, at 1:48 PM, Smith, Todd <[email protected]> wrote: > > In some of the reading that I have been doing in this subject over the years, > it might also be a ASIC vs CPU problem as well. Some vendors have in > advertising IPv6 support fail to mention that IPv6 is being done by the CPU > and not the custom switching and routing ASIC. Obviously this will impact > performance greatly depending on the hardware and lab-scale or benchtop > testing will not show that the CPU has less headroom then a ASIC at high > packet counts. > > Todd Smith > > Charleston Area Medical Center > > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > [mailto:[email protected]] On Behalf Of Turner, Ryan H > Sent: Friday, September 09, 2016 14:16 > To: [email protected] > Subject: Re: [WIRELESS-LAN] IPv6 issues > > You are likely going to have a lot of problems with IPv6 depending on how big > of an ARP table your router can support. We are currently evaluating our > next gen platform for routing on campus, and with many of us having very > large subnet spaces to enable wireless mobility, you are going to see a lot > of issues with tables sizes with IPv6. For that reason, we aren’t going to > touch IPv6 with a ten foot pole on wireless anytime soon (we currently run > IPv6 selectively across campus). We are currently experiencing significant > drops (ARP and DHCP) on an older 6509 platform that routes main campus > wireless. We have exceeded the 32k recommended ARP table size, and it is > showing. We are migrating our largest VLAN to a different router with more > head room (64k) until we figure out where we go next with the architecture. > > So, I think you are likely going to be needing to upgrade your hardware if > you have large SVIs for wireless. There is some debate about this depending > on what vendor we talk to, but the next gen Broadcom chipset is ‘supposed’ to > support over 700k ARP table size. > > > Ryan Turner > Manager of Network Operations > ITS Communication Technologies > The University of North Carolina at Chapel Hill > > [email protected] > +1 919 445 0113 Office > +1 919 274 7926 Mobile > > > > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > [mailto:[email protected]] On Behalf Of Dave Soltis > Sent: Friday, September 9, 2016 2:00 PM > To: [email protected] > Subject: [WIRELESS-LAN] IPv6 issues > > Good afternoon, > > Has anybody had any experience with turning on IPv6 for a mid-large size > University. > We turned up IPv6 during the summer and had no issues, but the first day of > classes > where we saw 30,000 concurrent devices we had issues with the upstream > routers routing > table exceeded(128k) and very high CPU. We have 5 Wism Blades in a 6513VSS HA > Configuration. > Maybe we need to distribute ? or upgrade hardware ? Any insights/suggestions > would be much appreciated. > > Thanks > > -- > Dave Soltis > Wireless Network Analyst > Information Services and Technology > University of Alberta > Ph.7804923144 > > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. > CONFIDENTIALITY NOTICE: The information contained in this > message may > be privileged and confidential. If this e-mail contains protected > health information, you are hereby notified that any dissemination, > distribution or copying of this communication is strictly prohibited, > except as permitted by law. If you have received this communication in > error, please notify the sender immediately by replying to this message > and deleting it from your computer. Thank you. > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. --- Bruce Curtis [email protected] Certified NetAnalyst II 701-231-8527 North Dakota State University ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
