Re: calculate saving ratio of *link bandwidth*

From: George Michaelson <>
Date: Fri, 12 Jun 1998 19:34:44 +1000

You're asking how to reconcile an IP/octet count such as SNMP counts on
interfaces, or netflow/netramet/nnstat counts, against the applications
only view?

Thats around 10% isn't it? similar in fact to the back-channel load of
ACK and the initial request, if you are a fetch-pays customer on a network
and serve outbound (uncharged) data in terms of what you pay.

Why similar? because the majority of the back=data is pure ACK and other TCP
overhead so its within an order of scale to the overheads on top of the served

DNS adds a bit more. If you don't do DNS, you save traffic.

This is an intersting area. We're running a mirror (the cousin to a cache)
and we notice marked parallels in the curve-shapes between bothe methods
of count, but clear differences too!

Anyway, I'd suggest you do some monitoring like netflow/snmp/nnstat/netramet
to get your handle on the overhead costs of TCP+FTP and TCP+HTTP and then
use the hitrate, and measured object size to determine the overall packet

Received on Fri Jun 12 1998 - 02:35:57 MDT

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