We are experiencing occasionally high levels of input drops/receive discards on the 3660 router that connects our central site (300+ nodes) to the internet via a 100MB link. The prevailing consensus has been - it's an old, verging-on-obsolete router that is simply unable to keep up with the demands that an 100MB link (and the user community addicted to it) makes. However, due to the current economic situation, we are stuck with the device for at least one more year so we are trying to make the best of it.
On to the meat of the matter ...
As inferred above, we have been using this 3660 as our main Internet router for quite a few years. This router used to have dual T1 lines from providers going into it. Now it has the single 100MB internet feed from an ISP going into it. The router is running a rather aged IOS of 12.2(23). We have been investigating loading a newer 12.2 mainline IOS - 12.2(46a), any recommendations to do this to help resolve the high amount of input drops/receive discards we get from time to time?
In researching the issue, we came across a document on Cisco's website "Troubleshooting Input Queue Drops and Output Drops."
Following the steps recommended in troubleshooting our specific issue (input drops), we came across the mention of CEF (Cisco Express Forwarding.)
We issued a SHOW IP INT FA 1/0 command and discovered that while fast switching is indeed enable, both IP Flow (Netflow?) and Cisco Express Forwarding are disabled.
Would enabled either one or both these be of any assistance in reducing the input drops?
If so, while we understand CEF would have to be configured both globally and on the specific interface with the input drop issue (obviously this is the ethernet interface that has the 100MB link coming into it), we are confused somewhat by the apparent restriction of "logging disables CEF." Does this logging restriction only apply to the application of the log keyword to an access-list on this router? Or does this apply to any sort of logging (console, syslog, etc.?) We don't think so, but want to make sure.
Lots of questions here - hopefully they have been presented clearly enough for all of you.