Most of the documentation I can find on "Pending routes" from show ip eigrp interfaces comes directly from Cisco and is not that helpful.
Their definition is "Number of routes in the packets sitting in the transmit queue waiting to be sent."
The reason for this question is that we have an EIGRP meltdown on our core routers (6500s - Sup720) about every three months. We created scripts to collect more data from the router on a 5 minute interval and the early indication that EIGRP was in trouble was that there were
52 out of approximately 300 EIGRP interfaces that had as many as 8000 pending routes. The remainder of the interfaces had zero pending routes. The IP routing table is approximately 4000 routes.
The CPU utilization was 34% at 5 sec with 11% consumed by EIGRP PDM.
Five minutes later the CPU was at 100% and Pending routes were as high as 100,000 on some of the EIGRP interfaces. All interfaces with EIGRP neighbors had tens of thousands of pending routes.
This core router (Core_01) has another core router attached (Core_02) and it did not record a high number of Pending routes.
There was no indication in the syslog of any significant topology change leading up to or during this event.
So my questions to the group are;
1. Does anyone have a better definition of Pending routes?
2. How often are the counters from show ip eigrp interface updated by the IOS?
3. Does 8000 Pending routes seem to high considering that there are only 4000 routes in the IP routing table?
Thanks in advance