On Wednesday 08 August 2001 08:50, Rusty Carruth wrote:
> David Oberbeck <[EMAIL PROTECTED]> wrote:
> > Greetings,
> >
> > Is your network using hubs or a switches?
>
> Um, not meaning to be rude, but: He already said that his
> computer is plugged into a hub. However, I was wondering
> what THAT hub was plugged into, and if there are any other
> computers plugged into that hub that he could make access
> the network.
Yes, your question is a valid one - what is the rest of the network
topology? Are there switches upstream?
(Somewhat OT: Sadly, rudeness is what I have come to expect, even
in forums such as this.
Many times, when attempting to help people, it is necessary to
'calibrate' the level at which you are communicating. I have found a
surprising number of people who use the terms 'hub' and 'switch'
interchangeably)
> >
> > > BTW: The label on the box where my ws is plugged into plainly says
> > > "Dual speed 16-port Ethernet/Fast Ethernet Hub" so this is not switch.
> > > ;-)
> Hmm. Question - what are the network speeds for all the NICs
> hooked to that 'hub'? What's the uplink speed?
> *IF* the uplink is 100, and YOU are 10, then it seems like
> the 'hub' cannot act ENTIRELY like a 'dumb hub', else you'd
> not be able to get all the packets that might be sent to
> you. (Anybody know what happens to a 10/100 HUB when a 100
> side streams more than 10 MB/s at a 10MB side???? Or, more
> to the point of THIS situation - what happens when the
> total traffic on all segments is greater than the rx bandwidth
> of one of the receivers? In other words, HOW can a 10/100
> 'HUB' be a PURE hub???? (and not have any features of a
> switch)).
It's not a 'pure hub'. Older hubs were single-speed: Analog
wigglies came in, they were re-clocked then re-transmitted to all
(other, e.g. not the one the packet came in on) ports. Multi-speed
hubs are digital in between the goes-inta and goes-outa, and do not
have a strict time relationship between the ports.
FYI, in the case of a multi-speed configuration (e.g. 10/100 mix) a
digital hub spools some (small) number of packets, then dumps the
rest. If the destination was on the slow side, the originating host
will re-transmit the packet when it doesn't get a response from the
packet(s) that the hub dropped. Switches generally have larger buffers
when going from a faster to slower ports, but if there is too much
higher-speed traffic then it, too, will dump packets as with a hub.
Managed switches can be interrogated for statistics on exactly this
kind of occurrance.
> Its early, and I'm incoherent, so I hope this makes sense ;-)
>
> rc
>
>
> Rusty E. Carruth Email: [EMAIL PROTECTED] or
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--
"Entropy Requires No Maintenance"
