I have a LAN extention network (All l2 arpa encap) with L3 switches on each of the sites. Users are complaining of slow speeds.
I have ruled out misconfigs, interface errors, Processor Peaking, Log anomoies, Loops and routing instability, acl etc.
The only thing I can think of is that the delay could be is the 10Mbps LES circuits are not enough. How do I measure if the bandwidth is being maxed on the uplinks at the busy points of the day?
Do I need to run some IP Traffic analysis software such as cisco netflow or can I determine if we need more bandwidth from local switch commands?
"What does the /255 mean? How long a timeframe is this over? "
/255 is the divisor, so 21/255 = 8.24% (255 was likely chosen since it's what a single byte can contain)
The timeframe, on most interfaces, defaults to 5 minutes. This can often be adjusted using the load-interval command within the interface configuration.