<div dir="ltr">On Tue, Oct 29, 2013 at 6:53 AM, Phil Mayers <span dir="ltr"><<a href="mailto:p.mayers@imperial.ac.uk" target="_blank">p.mayers@imperial.ac.uk</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im"><span style="color:rgb(34,34,34)">I wanted to follow up on this. Some folks from Cisco kindly contacted me off-list, and correctly guessed that a large number of the IPv6 neighbour entries were in state "STALE", and pointed me to the relatively new:</span><br>
</div><div class="im"><br>
<br>
ipv6 nd cache expire <seconds><br>
<br></div>
...interface-level command. This wasn't in the IOS train we were running until relatively recently, so I hadn't seen it before.<br></blockquote><div><br></div><div>I wonder what the designers were thinking when they did the original implementation. Without this option, a box with enough client churn could run out of neighbour cache entries even if all the clients are perfectly behaved.</div>
<div><br></div><div>Perhaps they didn't think of it because it doesn't happen in IPv4 due to a) much fewer addresses on a given box due to scarcity and b) ARP has timeouts.</div></div></div></div>