Monitor bandwidth between to locations?

Hello,

Is there a good little/simple tool to monitor and log the ongoing bandwidth
AVAILABLE (not used) between to ip addresses?

Thanks!
Matt

"Matt Landis" <matt(remove)@landiscomputer.com> wrote in message
news:(E-Mail Removed)...
> Hello,
>
> Is there a good little/simple tool to monitor and log the ongoing
bandwidth
> AVAILABLE (not used) between to ip addresses?

Sure (sort of) as they are the same tools.

Available bandwith is whatever is left if you
measure the bandwidth in use.

BUT, determining the maximum for many network
types is not straightfoward.

Since you are likely interested in Ethernets, you
should realize that an Ethernet at approximately
35-40 utilization is generally maxed out.

Before we start a bunch of bandwidth arguments
let's clarify: In a laboratory like setting with a
single client and a single server (doing all the
sending) there will never be any collisions etc
so the bandwidth might be used to near 100%
but with a number of machines communicating
on the same 10, 100, or 1000 Mbits network you
get about 3.5, 35, or 350 Mbits of realistic
bandwidth -- then the collisions and waits for
retry add up so that even if you SEE 90% you
probably get less than you did when you were
monitoring at 30%.

For serial lines and things like token ring where
access is negotiated (not dependent on collisions
and such) then about 90% of the nominal number
is realistic.

Thanks for the input, but I was looking for a "little tool recommendation"
more than the theretics of network topoplogies! ;-)

Matt

"Herb Martin" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Matt Landis" <matt(remove)@landiscomputer.com> wrote in message
> news:(E-Mail Removed)...
> > Hello,
> >
> > Is there a good little/simple tool to monitor and log the ongoing
> bandwidth
> > AVAILABLE (not used) between to ip addresses?
>
> Sure (sort of) as they are the same tools.
>
> Available bandwith is whatever is left if you
> measure the bandwidth in use.
>
> BUT, determining the maximum for many network
> types is not straightfoward.
>
> Since you are likely interested in Ethernets, you
> should realize that an Ethernet at approximately
> 35-40 utilization is generally maxed out.
>
> Before we start a bunch of bandwidth arguments
> let's clarify: In a laboratory like setting with a
> single client and a single server (doing all the
> sending) there will never be any collisions etc
> so the bandwidth might be used to near 100%
> but with a number of machines communicating
> on the same 10, 100, or 1000 Mbits network you
> get about 3.5, 35, or 350 Mbits of realistic
> bandwidth -- then the collisions and waits for
> retry add up so that even if you SEE 90% you
> probably get less than you did when you were
> monitoring at 30%.
>
> For serial lines and things like token ring where
> access is negotiated (not dependent on collisions
> and such) then about 90% of the nominal number
> is realistic.
>
>
>
>

"Matt Landis" <matt(remove)@landiscomputer.com> wrote in message
news:(E-Mail Removed)...
> Thanks for the input, but I was looking for a "little tool recommendation"
> more than the theretics of network topoplogies! ;-)

I think one point of what he is trying to say is that the tool wouldn't be
accuarte anyway and it would all be subject to "interpetation". As he
described,..the conditions that naturally exist make the reading you get
meaningless to a certain extent.

As far as the collisions, they can be eliminated by the use of Switches, but
then the Switches after a certain point introduce a processing lag due to
the additional processing they have to do on the packets. Networking is
simply a big balancing act.

As far as a Tool,..the plain old Network Monitor that comes with Windows
Server (since NT4) and the improved version that comes with Systems
Management Server has a measurment for bandwidth. How useful that is is up
for grabs. I assume Etherreal has similar features but I haven't used it
enough to say specifically.

SolarWinds produces many different network measuring tools, but get ready to
spend $$$$. There are no free lunches.

I personally prefer just the live "unscientific" method. Just find your
favorite large file and copy it from one machine to another and see how long
it takes. If it copies in a reasonable time frame then you are fine, if it
is unusually slow you have something choking things up. It ain't scientific
and doesn't give cute numbers (unless you time it and do math), but it has
worked for me. Contrary to the common "wizdom" the big bandwidth eaters are
not "streaming video" or other multimedia stuff,..the heaviest load on a
link comes from a simple file copy because it will always use everybit of
bandwidth it can grab, where streaming video/audio will stop when it hits
the bitrate the the audio or video is encoded at or streammed at.


--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com

"Matt Landis" <matt(remove)@landiscomputer.com> wrote in message
news:(E-Mail Removed)...
> Thanks for the input, but I was looking for a "little tool recommendation"
> more than the theretics of network topoplogies! ;-)
>


Then the answer is use any tool that gives usage and
subtract from nominal or expected bandwidth.

Netmon, Ethereal etc.

Thanks!


"Herb Martin" <(E-Mail Removed)> wrote in message
news:O$(E-Mail Removed)...
> "Matt Landis" <matt(remove)@landiscomputer.com> wrote in message
> news:(E-Mail Removed)...
> > Thanks for the input, but I was looking for a "little tool
recommendation"
> > more than the theretics of network topoplogies! ;-)
> >
>
>
> Then the answer is use any tool that gives usage and
> subtract from nominal or expected bandwidth.
>
> Netmon, Ethereal etc.
>
>