[117042] in North American Network Operators' Group
Re: Link capacity upgrade threshold
daemon@ATHENA.MIT.EDU (Shane Ronan)
Sun Aug 30 12:54:26 2009
From: Shane Ronan <sronan@fattoc.com>
To: Nick Hilliard <nick@foobar.org>
In-Reply-To: <4A9A7011.1010908@foobar.org>
Date: Sun, 30 Aug 2009 12:53:35 -0400
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
What system were you using to monitor link usage?
Shane
On Aug 30, 2009, at 8:26 AM, Nick Hilliard wrote:
> On 30/08/2009 13:04, Randy Bush wrote:
>> the normal snmp and other averaging methods *really* miss the bursts.
>
> Definitely. For fun and giggles, I recently turned on 30 second
> polling on some kit and it turned up all sorts of interesting
> peculiarities that were completely blotted out in a 5 minute average.
>
> In order to get a really good idea of what's going on at a
> microburst level, you would need to poll as often as it takes to
> fill the buffer of the port in question. This is not feasible in
> the general case, which is why we resort to hacks like QoS to make
> sure that when there is congestion, it is handled semi-sensibly.
>
> There's a lot to the saying that QoS really means "Quantity of
> Service", because quality of service only ever becomes a problem if
> there is a shortfall in quantity.
>
> Nick
>
