I am investigating several network performance issues. My hypothesis is that ICMP Unreachable packets are being discarded rather than relayed.
What I'm looking for is a discussion of the IOS processing steps that take place from the time that the packet arrives on an interface and all the steps until it is transmitted out the next interface.
It's been a few years since I worked with Cisco IOS with any degree of regularity. I see some items in configuration files that scream: "I'm in the wrong place".
I'm looking for additional inforation that might explain why.