Network management software with high detailed traffic report

Jon Lewis jlewis at lewis.org
Mon Nov 22 16:19:32 CST 2010


On Mon, 22 Nov 2010, Brandon Ross wrote:

> On Mon, 22 Nov 2010, Nick Hilliard wrote:
>
>> some do, some don't.  For example, sup720 snmp counters are updated every 9 
>> seconds, while the "show interface" counters are updated every 30 seconds.
>
> That is most certainly NOT true.  The 'show interface' counters update at 
> least once a second.  Perhaps you are thinking about the rate counters that 
> are often _configured_ to use the last 30 seconds of data to compute the 
> average but also update much more often than every 30 seconds (and default to 
> a 5 minute average).

I didn't think it was true either...but after reading Nick's message I 
checked a X6408A interface on one of our sup720's running "relatively" 
recent code (SXI1), and there definitely is some time between updates both 
the packet counters and the time averaged rates.

Just repeating the command and looking at my watch, I'd say Nick is right. 
It's easy to test yourself.  Pick an int, and repeat "sh int <int name> | 
inc packets.  The numbers really don't change but every 9 seconds or so. 
Same goes for the avg numbers...mine are set to 30 sec load interval, and 
they only change every ~9 seconds.

This does vary by platform.  3550 swiches and 7200 routers both seem to 
update the counters about 1/s.  Maybe the delayed updates are just a 6500 
thing.

----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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