10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by David Yua » Fri, 25 Jun 1999 04:00:00



This question may be too dumb. In my home network configuration, I have
a DFE-530TX in a linux (RH6.0) box, a PCMCIA 10base-t card in a win98
laptop. Both of them are connected to a dual speed (Ethernet/Fast
Ethernet) hub. I assigned the linux box to 192.168.1.1 and win98 to
192.168.1.2. From the hub, I can see the 10mbps light is on of the port
connecting laptop's NIC and 100mbps light on of the port connecting the
linux. But when I ping from linux to the win98, it just does not have
any response. The same thing to the laptop. Simply, these two machines
don't know each other at all. Strangely, if I assign same IP address to
both machines, pinging from linux, a window popped in the win98 saying
"The system has detected a conflict for IP address 192.168.1.1 with the
system having hardware address xx:xx:xx:xx:xx:xx". The address is my
linux NIC.

I must missed something basic in network wiring. Please someone tell me
what's wrong with the above configuration.

Thanks,

David

  david.yuan.vcf
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10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Rod Smi » Fri, 25 Jun 1999 04:00:00


[Posted and mailed]



Quote:

> This question may be too dumb. In my home network configuration, I have
> a DFE-530TX in a linux (RH6.0) box, a PCMCIA 10base-t card in a win98
> laptop. Both of them are connected to a dual speed (Ethernet/Fast
> Ethernet) hub. I assigned the linux box to 192.168.1.1 and win98 to
> 192.168.1.2. From the hub, I can see the 10mbps light is on of the port
> connecting laptop's NIC and 100mbps light on of the port connecting the
> linux. But when I ping from linux to the win98, it just does not have
> any response. The same thing to the laptop. Simply, these two machines
> don't know each other at all. Strangely, if I assign same IP address to
> both machines, pinging from linux, a window popped in the win98 saying
> "The system has detected a conflict for IP address 192.168.1.1 with the
> system having hardware address xx:xx:xx:xx:xx:xx". The address is my
> linux NIC.

> I must missed something basic in network wiring. Please someone tell me
> what's wrong with the above configuration.

Sounds more like a configuration problem on one or both systems to me.
Most NICs have transmit LEDs, and these should flicker when you try to
access the net.  Ditto for hubs.  Check these lights to be sure you're
getting SOMETHING going in and out on the pings.

Try going over your other networking options, like system names, gateways,
installed protocols, etc.  Check to be sure that your eth0 device is
installed in Linux.

--
Rod Smith

http://www.channel1.com/users/rodsmith
NOTE: Remove the "uce" word from my address to mail me
Author of _Special Edition Using WordPerfect for Linux_, from Que;
see http://www.channel1.com/users/rodsmith/books.html

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Mark Pric » Fri, 25 Jun 1999 04:00:00


Hi David,

THe problem is that although the hub is dual speed, 10/100, it can only
be in one mode at a time. So all hosts need to be either 10Mb, or all
100Mb not a combination of the both.

In order to have a combination of the both, you would need a switch. A
switch provides the circuitry to buffer traffic coming in on a 100Mb
port
before forwarding it to a 10Mb port. A hub does not provide this.

Cheers, Mark.

Quote:> I must missed something basic in network wiring. Please someone tell me
> what's wrong with the above configuration.

> Thanks,

> David

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Mark Pric » Fri, 25 Jun 1999 04:00:00


Quote:> Depends on the model of hub. The NetGear DS104 hub ( and the equivalent
> 6-, 8- and 16-port models ) is a 10/100 per-port hub that allows
> mixing of 10-megabit and 100-megabit NICs on the hub without any
> problems.

Thanks for the info, this is a new one for me. Are there many
manufacturers doing this ?

Mark.

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Todd Knar » Sat, 26 Jun 1999 04:00:00



> In order to have a combination of the both, you would need a switch. A
> switch provides the circuitry to buffer traffic coming in on a 100Mb
> port before forwarding it to a 10Mb port. A hub does not provide this.

Depends on the model of hub. The NetGear DS104 hub ( and the equivalent
6-, 8- and 16-port models ) is a 10/100 per-port hub that allows
mixing of 10-megabit and 100-megabit NICs on the hub without any
problems.

--
Collin was right. Never give a virus a missile launcher.
                                -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Jér?me PETAZZO » Sat, 26 Jun 1999 04:00:00


[mixing 10 mbps & 100 mbps]

Quote:> > Depends on the model of hub. The NetGear DS104 hub ( and the equivalent
> > 6-, 8- and 16-port models ) is a 10/100 per-port hub that allows
> > mixing of 10-megabit and 100-megabit NICs on the hub without any
> > problems.

I recommend using a switch, because some 10/100 hubs are realy pigs
when it's about forwarding 100 mbps traffic to 10 mbps collision domain.

some hubs have a "switch module" options, it does not turn the hub into
a switch, it adds a 2 ports switch between the 10 mbps collision
domain and the 100 mbps one.

if you only have a small network at home or at a small office, I would
recommend using a low end PC with a 10 mbps NIC and a 100 mbps NIC
to do the forwarding - it will also give other services.
(I say low end because there is no need to process the 100 mbps
at full wire speed - just the 10 mbps...)
you can partition you lan between subnets or use the bridge functionality
in the linux kernel, which acts exactly like a switch, learning the
network topology.

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Todd Knar » Sun, 27 Jun 1999 04:00:00



> Thanks for the info, this is a new one for me. Are there many
> manufacturers doing this ?

I've seen more per-hub dual-speed hubs than per-port ones. This
is probably changing, but right now I'm conservative. NetGear tends
to be higher-end than most, they're the consumer label for Bay
Networks.

--
Collin was right. Never give a virus a missile launcher.
                                -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Todd Knar » Sun, 27 Jun 1999 04:00:00



> I recommend using a switch, because some 10/100 hubs are realy pigs
> when it's about forwarding 100 mbps traffic to 10 mbps collision domain.

Yes, I see this sometimes with the DS104. Traffic from the 100mbps segment
tends to swamp the 10mbps one. OTOH on a home network traffic tends to
short-term bursts and the hub seems to keep at least some of the traffic
between 100mbps machines off the 10mbps ports, so it shouldn't be too
bad for low-load use at home. You're right, though, once you start seeing
10% or more utilization over long periods, it's time to start considering
a switch.

Quote:> some hubs have a "switch module" options, it does not turn the hub into
> a switch, it adds a 2 ports switch between the 10 mbps collision
> domain and the 100 mbps one.

The docs on the NetGear DS family indicate that they have an internal
intelligent bridge between the 10mbps and 100mbps segments of the hub,
which is supposed to keep unneeded traffic from crossing between segments.
I think that's close to what you're talking about.

--
Collin was right. Never give a virus a missile launcher.
                                -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Rod Smi » Sun, 27 Jun 1999 04:00:00





>> In order to have a combination of the both, you would need a switch. A
>> switch provides the circuitry to buffer traffic coming in on a 100Mb
>> port before forwarding it to a 10Mb port. A hub does not provide this.

> Depends on the model of hub. The NetGear DS104 hub ( and the equivalent
> 6-, 8- and 16-port models ) is a 10/100 per-port hub that allows
> mixing of 10-megabit and 100-megabit NICs on the hub without any
> problems.

I'm interested in finding out more about the features and capabilities of
hubs and switches -- not so much specific brand recommendations as just
general information that could be used to evaluate them in the future.  Is
there a FAQ on this topic, or a section of some other FAQ devoted to it?
A manufacturer's web site with more than smokescreen marketing babble?

--
Rod Smith

http://www.channel1.com/users/rodsmith
NOTE: Remove the "uce" word from my address to mail me
Author of _Special Edition Using WordPerfect for Linux_, from Que;
see http://www.channel1.com/users/rodsmith/books.html

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Todd Knar » Mon, 28 Jun 1999 04:00:00



> I'm interested in finding out more about the features and capabilities of
> hubs and switches -- not so much specific brand recommendations as just
> general information that could be used to evaluate them in the future.  Is
> there a FAQ on this topic, or a section of some other FAQ devoted to it?
> A manufacturer's web site with more than smokescreen marketing babble?

I'm not sure of a FAQ, beyond general Ethernet technical texts, but
someone will probably chime in with one. There's a good selection of
FAQs at ftp://rtfm.mit.edu/pub/ if you want to browse through there.

The main difference from a user's POV between a hub and a switch is in
where the packets go. On a hub, any packet that comes in any port is
sent back out all ports except the one it came in on. A switch watches
for which Ethernet hardware (MAC) addresses send packets in through which
ports and builds a table of which MAC addresses are attached where. When
a packet comes in, the switch looks at the MAC address it's being sent
to and, if the address is in the table, only sends the packet out the
port that MAC address can be reached through.

--
Collin was right. Never give a virus a missile launcher.
                                -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by TURBO101 » Fri, 02 Jul 1999 04:00:00


Is this the reason why if I'm copying something from my desktop to linux,
the light on the nic on my laptop blinks too?



> > I'm interested in finding out more about the features and capabilities
of
> > hubs and switches -- not so much specific brand recommendations as just
> > general information that could be used to evaluate them in the future.
Is
> > there a FAQ on this topic, or a section of some other FAQ devoted to it?
> > A manufacturer's web site with more than smokescreen marketing babble?

> I'm not sure of a FAQ, beyond general Ethernet technical texts, but
> someone will probably chime in with one. There's a good selection of
> FAQs at ftp://rtfm.mit.edu/pub/ if you want to browse through there.

> The main difference from a user's POV between a hub and a switch is in
> where the packets go. On a hub, any packet that comes in any port is
> sent back out all ports except the one it came in on. A switch watches
> for which Ethernet hardware (MAC) addresses send packets in through which
> ports and builds a table of which MAC addresses are attached where. When
> a packet comes in, the switch looks at the MAC address it's being sent
> to and, if the address is in the table, only sends the packet out the
> port that MAC address can be reached through.

> --
> Collin was right. Never give a virus a missile launcher.
>                                 -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by Todd Knar » Sat, 03 Jul 1999 04:00:00



> Is this the reason why if I'm copying something from my desktop to linux,
> the light on the nic on my laptop blinks too?

More than likely. It's a simpler design, hence why hubs are cheaper
than switches. The tradeoff is efficiency.

--
Collin was right. Never give a virus a missile launcher.
                                -- Erk, Reality Check #8

 
 
 

10BASE-T NIC and 100mbps NIC to a dual-speed hub doesn't work?

Post by bill davids » Thu, 08 Jul 1999 04:00:00




| > Is this the reason why if I'm copying something from my desktop to linux,
| > the light on the nic on my laptop blinks too?
|
| More than likely. It's a simpler design, hence why hubs are cheaper
| than switches. The tradeoff is efficiency.

Efficiency is a somewhat broad term, bandwidth is the issue. In a hub,
if A has a socket to B and C to D, they each see every packet, a so have
only 10Mbit (or 100Mbit) to share for all machines. In a switch the
shared limit is the bandwidth of the backplane of the switch, usually
500MB to 5GB, so both sockets can run at full speed.

This can make a huge difference in latency and throughput for a system
where traffic is distributed.

--

  The Internet is not the fountain of youth, but some days it feels like
the fountain of immaturity.