half duplex

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half duplex

larinia@gmail.com
Hello list,

I am running debian unstable version on my laptop, for some reason, the
eth0 is running under half duplex. The interface does come up and I do
have internet access, I am just wondering if there is a way I can make
it working under full duplex. Can anyone help?

Thanks a lot

Larinia


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Re: half duplex

Doofus
larinia wrote:

> Hello list,
>
> I am running debian unstable version on my laptop, for some reason,
> the eth0 is running under half duplex. The interface does come up and
> I do have internet access, I am just wondering if there is a way I can
> make it working under full duplex. Can anyone help?
>
> Thanks a lot
>
> Larinia


Hello.
How do you know you're running at half duplex?
What's the other end of your cat-5 cable connected to?


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Re: half duplex

larinia@gmail.com
Hello,

I saw the half duplex message in the /var/log/syslog. I am not sure if
the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
then it is connecting to a hub, which is then connect to a wireless bridge.

Doofus wrote:

> larinia wrote:
>
>> Hello list,
>>
>> I am running debian unstable version on my laptop, for some reason,
>> the eth0 is running under half duplex. The interface does come up and
>> I do have internet access, I am just wondering if there is a way I
>> can make it working under full duplex. Can anyone help?
>>
>> Thanks a lot
>>
>> Larinia
>
>
>
> Hello.
> How do you know you're running at half duplex?
> What's the other end of your cat-5 cable connected to?
>
>


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Re: half duplex

Patrick Dreker
Am Freitag, 29. Juli 2005 12.51 schrieb larinia:
> then it is connecting to a hub, which is then connect to a wireless bridge
If the other device really is a hub, then half-duplex is the best you'll get.
Only switches can do full duplex...

Patrick


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Re: half duplex

ze phyr
In reply to this post by larinia@gmail.com
On 08:57 Fri 29 Jul     , larinia wrote:
> Hello list,
>
> I am running debian unstable version on my laptop, for some reason, the
> eth0 is running under half duplex. The interface does come up and I do
> have internet access, I am just wondering if there is a way I can make
> it working under full duplex. Can anyone help?

The simple way to know whether you are using half-duplex or not is run:

ethtool

you can use it to change NIC's mode.

I deliberately changed mine into half-duplex/10M because if it is
100M/duplex, the connection is very slow with my pppoe link.

Don't worry too much if you are using a 10M network anyway.

regards

bxuef

--
dhammapada says:
 
  Who will master this world and the world of Death with its devas? Who
  will gather well taught aphorisms (dhammapadas), like an connoisseur
  picking a flower? 44
 
  A disciple will master this world and the world of Death with its devas.
  A disciple will gather well taught aphorisms (dhammapadas), like a
  connoisseur picking a flower. 45
 


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Re: half duplex

geromanas (Bugzilla)
In reply to this post by larinia@gmail.com
2005 m. Liepos 29 d., Penktadienis 13:51, larinia rašė:
> I saw the half duplex message in the /var/log/syslog. I am not sure if
> the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
> then it is connecting to a hub, which is then connect to a wireless bridge.
If the other end is a hub, it may not be capable of doing full-dupex, so both
ends autonegiotiated the half-duplex mode (both ends must run in the same
(either full or half) duplex). AFAIK, linux defaults to full-duplex whether
possible. Nevertheless, there is nothing wrong with half-duplex, it's just
the way signals are sent over a wire. You don't need to worry about this.

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Re: half duplex

Dietz Proepper-5
In reply to this post by larinia@gmail.com
larinia:
> I saw the half duplex message in the /var/log/syslog. I am not sure if
> the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,

It is.

> then it is connecting to a hub, which is then connect to a wireless
> bridge.

That's the point. A hub can only give you a half duplex connection as
opposed to a switch. For an explanation see [1].  But it should not matter
in your setup cause the wireless bridge will be the bottleneck anyway.

[1] i.e. http://www.duxcw.com/faq/network/hubsw.htm


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Re: half duplex

Nick Leverton
In reply to this post by larinia@gmail.com
On Fri, Jul 29, 2005 at 11:51:23AM +0100, larinia wrote:
> Hello,
>
> I saw the half duplex message in the /var/log/syslog. I am not sure if
> the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
> then it is connecting to a hub, which is then connect to a wireless bridge.

Run "mii-tool -v" and see what it says.  It doesn't work on all network
adaptors, I'm especially unsure about the embedded type you get in
laptops.

But if it works, the "link partner" line will tell you whether the
hub can do full-duplex, and if you paste the output here we can see if
there's anything wrong.

Please either keep debian-kde in or CC me directly, thank you
Nick


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Re: half duplex

larinia@gmail.com
In reply to this post by Dietz Proepper-5
ehm, thank you all very much, I will try to connect my laptop directly
with the modem and see if there is any difference.

Does half duplex make the network traffic slower?

Dietz Proepper wrote:

>larinia:
>  
>
>>I saw the half duplex message in the /var/log/syslog. I am not sure if
>>the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
>>    
>>
>
>It is.
>
>  
>
>>then it is connecting to a hub, which is then connect to a wireless
>>bridge.
>>    
>>
>
>That's the point. A hub can only give you a half duplex connection as
>opposed to a switch. For an explanation see [1].  But it should not matter
>in your setup cause the wireless bridge will be the bottleneck anyway.
>
>[1] i.e. http://www.duxcw.com/faq/network/hubsw.htm
>
>
>  
>


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Re: half duplex

Doofus
In reply to this post by larinia@gmail.com
larinia wrote:

> Hello,
>
> I saw the half duplex message in the /var/log/syslog. I am not sure if
> the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
> then it is connecting to a hub, which is then connect to a wireless
> bridge.
>
> Doofus wrote:
>
>> larinia wrote:
>>
>>> Hello list,
>>>
>>> I am running debian unstable version on my laptop, for some reason,
>>> the eth0 is running under half duplex. The interface does come up
>>> and I do have internet access, I am just wondering if there is a way
>>> I can make it working under full duplex. Can anyone help?
>>>
>>> Thanks a lot
>>>
>>> Larinia
>>
>>
>>
>>
>> Hello.
>> How do you know you're running at half duplex?
>> What's the other end of your cat-5 cable connected to?
>

Tell us the make and model of your hub and maybe we can quickly find out
if it'll talk duplex. Generally speaking you need a proper ethernet switch.

There are quite a few instances of some switch gear being incompatible
with some network interfaces when relying on Auto N-way.  Cisco and Sun
HappyMeals probably the best example. In these cases you need to have
only one of the two running auto-negotiation and the other hard set to
run 100MB/FD.


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Re: half duplex

Vincent Bernat
In reply to this post by Nick Leverton
OoO Peu  avant le début de  l'après-midi du vendredi  29 juillet 2005,
vers 13:46, Nick Leverton <[hidden email]> disait:

>> I saw the half duplex message in the /var/log/syslog. I am not sure if
>> the cat-5 cable is the network cable(Sorry, I am a newbie), if it is,
>> then it is connecting to a hub, which is then connect to a wireless bridge.

> Run "mii-tool -v" and see what it says.  It doesn't work on all network
> adaptors, I'm especially unsure about the embedded type you get in
> laptops.

On adapters that don't work, ethtool may work.
--
Make input easy to prepare and output self-explanatory.
            - The Elements of Programming Style (Kernighan & Plauger)


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Re: half duplex

Dietz Proepper-5
In reply to this post by larinia@gmail.com
larinia:
> ehm, thank you all very much, I will try to connect my laptop directly
> with the modem and see if there is any difference.

You need another cable (or a rather intelligent nic or modem;) for this.

> Does half duplex make the network traffic slower?

It does. But as I already said, this should not matter in your situation,
because that bridge (or modem or whatever) will be the bottleneck.
Therefore, simply leave it as it is.


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Re: half duplex

larinia@gmail.com
I have done "mii-tool -v", here is the outcome

 eth0: negotiated 100baseTx-HD, link ok
  product info: vendor 00:40:63, model 50 rev 8
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
  link partner: 100baseTx-HD 10baseT-HD

I think the hub does support full duplex. It is netgear dual speed hub model DS104.



On 7/29/05, Dietz Proepper <[hidden email]> wrote:
larinia:
> ehm, thank you all very much, I will try to connect my laptop directly
> with the modem and see if there is any difference.

You need another cable (or a rather intelligent nic or modem;) for this.

> Does half duplex make the network traffic slower?

It does. But as I already said, this should not matter in your situation,
because that bridge (or modem or whatever) will be the bottleneck.
Therefore, simply leave it as it is.


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Re: half duplex

Nick Leverton
On Fri, Jul 29, 2005 at 10:13:41PM +0100, Lei Yu wrote:
> I have done "mii-tool -v", here is the outcome
>
 *snips*
> link partner: 100baseTx-HD 10baseT-HD
>
> I think the hub does support full duplex. It is netgear dual speed hub model
> DS104.

The hub is telling your eth0 that it doesn't - only half duplex (HD),
at 100 Mbits or 10 Mbits.  To find out if it actually does FD, you can
try forcing full duplex temporarily with "mii-tool -F 100baseTx-FD eth0".
Watch the output from "ifconfig eth0" to see if the Errors or Collisions
start going wild, which will indicate that the hub doesn't do full duplex.

Having said that, Amazon have the manual online, linked in from
http://www.amazon.com/exec/obidos/tg/detail/-/B00000J4LQ/002-4342910-3697617?v=glance
and the Troubleshooting section says to ensure the conected PC is set
to half dulpex, so it looks like the hub is only HD I'm afraid.

Regrets,

Nick


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Re: half duplex

larinia@gmail.com
Thanks a lot for your help. :-)

Nick Leverton wrote:
On Fri, Jul 29, 2005 at 10:13:41PM +0100, Lei Yu wrote:
  
I have done "mii-tool -v", here is the outcome

    
 *snips*
  
link partner: 100baseTx-HD 10baseT-HD

I think the hub does support full duplex. It is netgear dual speed hub model 
DS104.
    

The hub is telling your eth0 that it doesn't - only half duplex (HD),
at 100 Mbits or 10 Mbits.  To find out if it actually does FD, you can
try forcing full duplex temporarily with "mii-tool -F 100baseTx-FD eth0".
Watch the output from "ifconfig eth0" to see if the Errors or Collisions
start going wild, which will indicate that the hub doesn't do full duplex.

Having said that, Amazon have the manual online, linked in from
http://www.amazon.com/exec/obidos/tg/detail/-/B00000J4LQ/002-4342910-3697617?v=glance
and the Troubleshooting section says to ensure the conected PC is set
to half dulpex, so it looks like the hub is only HD I'm afraid.

Regrets,

Nick

  
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Re: half duplex

Dietz Proepper-5
In reply to this post by Nick Leverton
You:

> On Fri, Jul 29, 2005 at 10:13:41PM +0100, Lei Yu wrote:
> > I think the hub does support full duplex. It is netgear dual speed hub
> > model DS104.
>
> The hub is telling your eth0 that it doesn't - only half duplex (HD),
> at 100 Mbits or 10 Mbits.  To find out if it actually does FD, you can
> try forcing full duplex temporarily with "mii-tool -F 100baseTx-FD
> eth0". Watch the output from "ifconfig eth0" to see if the Errors or
> Collisions start going wild, which will indicate that the hub doesn't do
> full duplex.

Sorry to say this again - if it's a HUB it will never - never - never
support  FD. Hubs generally only support HD links due to their design.

Switchs can and normally do support FD.

But this does not matter normally, the slowdown is acceptable, at least for
SOHO and smaller kinds of setups.


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Re: half duplex

Jeff Coppock
In reply to this post by larinia@gmail.com
Lei Yu wrote:
> I think the hub does support full duplex. It is netgear dual speed hub
> model DS104.

These "dual-speed" hubs are still hubs.  They simply provide a single
switch (bridge) between the 10Mbps and the 100Mbps segments.  Essentially,
it combines a 10Mbps hub and a 100Mbps hub into a single unit and then a
switch circuit connects the two.

So, being a hub (repeater), only half duplex is supported.

jc

--
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Diggin' Debian Admin and User


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Re: half duplex

Paul Johnson
On Tuesday 02 August 2005 01:45 pm, Jeff Coppock wrote:
> Lei Yu wrote:
> > I think the hub does support full duplex. It is netgear dual
> > speed hub model DS104.
>
> These "dual-speed" hubs are still hubs.  They simply provide a
> single switch (bridge) between the 10Mbps and the 100Mbps segments.
>  Essentially, it combines a 10Mbps hub and a 100Mbps hub into a
> single unit and then a switch circuit connects the two.

Aren't home-user oriented dual-speed ethernet devices typically
implemented in the form of a switch?

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Re: half duplex

Jeff Coppock
Paul Johnson wrote:

> On Tuesday 02 August 2005 01:45 pm, Jeff Coppock wrote:
>
>>Lei Yu wrote:
>>
>>>I think the hub does support full duplex. It is netgear dual
>>>speed hub model DS104.
>>
>>These "dual-speed" hubs are still hubs.  They simply provide a
>>single switch (bridge) between the 10Mbps and the 100Mbps segments.
>> Essentially, it combines a 10Mbps hub and a 100Mbps hub into a
>>single unit and then a switch circuit connects the two.
>
>
> Aren't home-user oriented dual-speed ethernet devices typically
> implemented in the form of a switch?

Not from what I see.  But both are available, you're just gonna pay more
for a "switch" than for a "hub" since there is more circuitry in the switch.

If the dual-speed ethernet device says "hub", each unit has a built-in
self-learning bridge which provides the communications link between the 10
and 100 Mbps network devices. The intelligent bridge automatically manages
network traffic such that 100 Mbps traffic does not unnecessarily crowd the
10 Mbps network segment and 10 Mbps traffic does not crowd the 100 Mbps
segment.

If the dual-speed ethernet device says "switch", then each port is bridged
individually, so each port supports both HD and FD.

jc

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Diggin' Debian Admin and User


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Re: half duplex

larinia@gmail.com
In reply to this post by ze phyr
Thank you everyone, you've been great help to me!

phyrster wrote:

> On 08:57 Fri 29 Jul     , larinia wrote:
>
>>Hello list,
>>
>>I am running debian unstable version on my laptop, for some reason, the
>>eth0 is running under half duplex. The interface does come up and I do
>>have internet access, I am just wondering if there is a way I can make
>>it working under full duplex. Can anyone help?
>
>
> The simple way to know whether you are using half-duplex or not is run:
>
> ethtool
>
> you can use it to change NIC's mode.
>
> I deliberately changed mine into half-duplex/10M because if it is
> 100M/duplex, the connection is very slow with my pppoe link.
>
> Don't worry too much if you are using a 10M network anyway.
>
> regards
>
> bxuef
>
> --
> dhammapada says:
>  
>   Who will master this world and the world of Death with its devas? Who
>   will gather well taught aphorisms (dhammapadas), like an connoisseur
>   picking a flower? 44
>  
>   A disciple will master this world and the world of Death with its devas.
>   A disciple will gather well taught aphorisms (dhammapadas), like a
>   connoisseur picking a flower. 45
>  
>
>


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