Final update:<br><br> After much testing in the lab and working with Cisco TAC (almost no help),<br>
I have reached a conclusion about the problem - its a hardware limitation.<br>
<br> Enabling IPV6 routing on a 6500 (with XL cards) and a full Internet routing<br>
table in a VRF exceeds the limits of SP processing, The SP goes to 99%<br>
utilization reconfiguring something but eventually recovers. In the lab<br>
this took almost 5 minutes! In real life with many 10Gb interfaces active<br>
- who knows!!<br>
<br> The problem is that the router still passes enough traffic that EIGRP and BGP stay<br>
up, but all user traffic is "black hole'd" due to the 1-10kbs effective throughput.<br><br>
It looks like this may be a one time event, but neither Cisco TAC or the BU<br>
could say for sure this wouldn't happen again under some kind of BGP flap<br>
of VRF reconfig.<br>
<br> Our TCAM limit is 512K ipV4 routes now and we have 409K routes today.<br><br>
We will probably resort to filtering down the BGP learned routes to 100-200K and <br> then default for everything else to our Internet routers and then go shopping<br>
for a new router.<br>
<br> The problem isn't noticeable until we have more than about 250K routes.<br>
<br>
There was no interest in redesigning the network to not use VRFs for the<br>
Internet table. <br><br> Once IPV6 is enabled and all is stable we will probably go shopping for new routers.<br>
<br>
Thanks again for everyone's suggestions, it helped us figure out the root<br>
cause.