Ethereal-users: RE: [Ethereal-users] Others' Traffic.. no HTTP?
The original post by me referred to a situation where two devices
using Realtek 8139 chip NICs were connected through a Linksys
"EtherFast 10/100 Auto Sensing 8port Workgroup Hub" model
EFAH08W. These were exchanging legal UDP frames. I believe
the NICs had autonegotiated to 100 Mbit.
In order to check the traffic we then connected an old DOS-based
analyzer using a 16bit ISA-bus SMC 8416 NIC running a DOS based
commercial analyzer product (from 1996). We could see
miscellaneous background traffic from other stations (ARP
requests and NetBios broadcasts) which led me to believe
the device was acting a a switch. We could not see the desired
UDP traffic.
When we connected the 2 test machines and the analyzer to
an old 4-port 10Mbit only Netgear hub, we got the desired
traffic. So this may be an issue of the "hub" being a switch,
rather than a speed negotiation issue, since the 10 Mbit
anlyzer was seeing other stations on the network broadcasting,
and I think everything here is now using 10/100 NICs except for
the old analyzer we tried.
One reason I like the DOS based analyzers, or Linux based is
that they don't do any of their own broadcasting. Windows-based
analyzers do send out NetBIOS which gets in the way. My old
analyzer doesn't support PCI based interrupts, so doesn't see
much use anymore since it won't take a 10/100 card. Suppose I
could try a different analyzer but the immediate need has passed
(verified the traffic flow).
Bob F
> On Tue, Nov 13, 2001 at 05:51:17PM -0500, Rob Stidman wrote:
> > My problem also involved a Linksys hub acting the same way, and I solved
> my
> > problem, also, with a netgear.
>
> Hmm. Linksys claim on their Web site that their hubs really are hubs:
>
> http://www.linksys.com/support/support.asp?spid=7
>
> which sayd
>
> Switch VS. Hub. All Linksys Switches provide for Full-Duplex
> speed and cut down the traffic on the network by sending the
> packets only to the port on the workstation is to receive the
> information. The Linksys hubs only operate at Half-Duplex speed
> and they broad cast a packet to all the nodes on the network...
>
> However, that paragraph goes on to say:
>
> ...(the Auto- sensing hubs broadcast the 10Mb packets to the port
> that operate at 10Mb only and broadcast the 100Mb packets to the
> ports that operate at 100Mb only.
>
> Was this (and the hub in the other example) an auto-sensing hub, with
> the sniffing done on a port with a different speed from the other ports?
> Or is the Linksys Web site making an incorrect claim (which I could
> believe is the case, given that a Google search for "Linksys switching
> hub" found references to the "Linksys Switching Hub EZXS16W" and to the
> EZXS55W switching hub, although the Linksys site refers to the EZXS16W
> and EZXS55W as switches)?
>
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