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]<mailto:[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
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