Since a span port is transmit only, there is no way it can "clog the switch." 
The pc might get bogged down, but the switch won't know or care.

-mel via cell

On Jan 30, 2009, at 5:57 AM, "Walt Henley" 
<[email protected]<mailto:[email protected]>> wrote:

That's all he will see unless he gets the NetFlow plugin operating on a switch 
or router in his network.  Or, he could have his PC connected to a SPAN port 
(not recommended, could clog the switch).  3kb/s of traffic is not going to 
kill his WS.  Pretty typical.  I have a site I'm working on currently with 
30kB/s of broadcast noise.  Not much in 100 mb/s links.

On Thu, Jan 29, 2009 at 10:49 PM, Burton Strauss III 
<<mailto:[email protected]>[email protected]<mailto:[email protected]>>
 wrote:
Well, what you are seeing is a varied collection of broadcast traffic...

ARP - address resolution protocol - is how you find an address on the LOCAL
segment.

NBNS - NetBIOS, a local (non-routable) protocol

MS NLB - Microsoft Network Load Balancing protocol

Etc.

-----Burton

-----Original Message-----
From: <mailto:[email protected]> 
[email protected]<mailto:[email protected]> 
[mailto:<mailto:[email protected]>[email protected]<mailto:[email protected]>]
 On Behalf Of
Martin Larsson
Sent: Thursday, January 29, 2009 6:47 AM
To: <mailto:[email protected]> [email protected]<mailto:[email protected]>
Subject: Re: [Ntop] Non IP Traffic

Everything is just running on my local machine, yes.
All I'm trying to do is to understand why my network-adapter is receiving
all that data. It looks like there's a fairly constant stream of about
3Kbits...

But thanks for the info, I'll do some more simple checks and notify my
admins.

M.

On Thu, Jan 29, 2009 at 3:27 PM, Walt Henley 
<<mailto:[email protected]>[email protected]<mailto:[email protected]>>
 wrote:
> This trace may not be telling you the whole story.  Did you put the
> Wireshark machine on a SPAN port or just run it locally connected at your
> PC?  If you ran it locally connected, then all you are seeing is your
> traffic and any broadcasts that come along.  Also, how are you collecting
> NTOP data?   Using NetFlow or Sflow or just with a local connection.
Could
> be that it is seeing the heartbeats and deciding they are not identifyable
> IP traffic.  Try running netflow on your ethernet switches (assuming they
> are Cisco)>
>
> On Thu, Jan 29, 2009 at 8:59 AM, Martin Larsson 
> <<mailto:[email protected]>[email protected]<mailto:[email protected]>>
> wrote:
>>
>> Thanks. WireShark was interesting, and overwhelming.
>> It seems there's a lot of "MS NLB Heartbeat" each containing 1510 bytes.
>> Could that be it?
>> I've attached a sample screenshot.
>>
>> On Thu, Jan 29, 2009 at 2:16 PM, Burton Strauss III
>> <<mailto:[email protected]>[email protected]<mailto:[email protected]>>
>>  wrote:
>> > It means ntop is seeing a lot of traffic that isn't recognizable as
>> > tcp/ip.
>> >
>> > Depending on your connection and what you are monitoring (network
>> > topology)
>> > this could be normal (i.e. traffic wrapped in something) or it could be
>> > odd.
>> >
>> > I usually recommend installing WireShark and letting it analyze a few
>> > dozen
>> > packets (they both use libpcap so they look at traffic the same way).
>> >  If
>> > WireShark calls it differently than ntop, you probably have exposed
some
>> > bug. If they both call it non-ip, then explain your topology and we can
>> > guide you.  If you aren't sure, grab & post a screen shot of a page of
>> > random traffic from WireShark, post it and we can read what you have
>> > from
>> > there...
>> >
>> > -----Burton
>> >
>> >
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: <mailto:[email protected]> 
>> > [email protected]<mailto:[email protected]> 
>> > [mailto:<mailto:[email protected]>[email protected]<mailto:[email protected]>]
>> >  On Behalf Of
>> > Martin Larsson
>> > Sent: Thursday, January 29, 2009 3:54 AM
>> > To: <mailto:[email protected]> [email protected]<mailto:[email protected]>
>> > Subject: [Ntop] Non IP Traffic
>> >
>> > I installed ntop because the system monitor told me my network was
>> > fairly
>> > active
>> > even though I wasn't actively sending or receiving anything.
>> > After about 1.5 hours of running, the traffic summary is showing me a
>> > lot of
>> > non-IP traffic.
>> >
>> > Total   26.4 MBytes [47,672 Pkts]
>> > IP Traffic      9.3 MBytes [26,718 Pkts]
>> > Fragmented IP Traffic   0 [0.0%]
>> > Non IP Traffic  17.1 MBytes
>> >
>> > What does that mean?
>> >
>> > M.
>> > _______________________________________________
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