Andrew, The 32 bit counters are a significant problem when using gigabit ethernet public peering interfaces. Needless to say, MAC accounting was not designed for gigabit speeds. Frequent polling is, sadly the only solution. If you write your own scripts, make sure to account for counter wrapping. - Dan on 1/20/05 9:45 AM, "druid@softdust.com" <druid@softdust.com> wrote:
On Wed, 2005-01-19 at 22:41, andrew matthews wrote:
Anyone have any suggestions on graphing peering on a cisco router? I'm using mrtg and i did mac address accounting but the numbers are off.
off in what sense? We use mac-accounting, snmp nad mrtg to graph per peer utilization. The following script is helpful
http://www.thiscow.com/dl/bgp-peers-1.5.pl
I reworked it to spit out the AS number instead of the ip address. The issue you then have is that multiple sessions with one As number all show as the same target. Which MRTG does not like. You can fix that as well of course in the script. And it does not "autoscan", which means that if people change their mac-address, you lose the data, until you rerun the script.
Another problem you might run into is counter wrapping. When polling every 5 minutes, some counters may wrap. (there is no 64 bit counter for the mac-address accounting). So you have to run it in short timeframes, causing more cpu utilization.
But all in all, mac-accounting and Netflow source-as give you a very good overview of your network flows.
Frank