half-duplex/full-duplex problem

half-duplex/full-duplex problem

Post by Steen Hans » Sat, 04 Mar 2000 04:00:00



I have a new Sun E10, that is connected to a network switch using a cat 3
cable. We had some problems getting the conenction to work, apparently the
machine and the switch could not agree on what speed to run at, so I have
manually set it to 10 MB.

However, I have noticed another problem, incoming traffic runs MUCH slower
than outbound, very noticeable with FTP.

It appears the line runs only half duplex. The network guys says the switch is
set for full duplex, but runs in half because the E10 requests it.

On the E10, I see the follwing, as I can understand from the manual. I have
not done much work with these settings, so I may miss something here.

It is set to do full duplex:
  # ndd /dev/hme 10fdx_cap
  1

No negotiation
  # ndd /dev/hme adv_autoneg_cap
  0

But it thinks the Link Partner (the switch, I presume) can not do
full duplex:

  # ndd /dev/hme lp_10fdx_cap
  0

But it reports it is doing full duplex.

  # ndd /dev/hme link_mode
  1

(I assume '1' means full, the manual is not real clear on that)

And it's set to only do full duplex.
  # ndd /dev/hme adv_10fdx_cap
  1
  # ndd /dev/hme adv_10hdx_cap
  0

Suggestions?

Thanks

 
 
 

half-duplex/full-duplex problem

Post by Robert Yode » Sat, 04 Mar 2000 04:00:00



> I have a new Sun E10, that is connected to a network switch using a cat 3
> cable. We had some problems getting the conenction to work, apparently the
> machine and the switch could not agree on what speed to run at, so I have
> manually set it to 10 MB.

That is very strange;  I've never seen a Sun require manual
setting of the speed.

Quote:> However, I have noticed another problem, incoming traffic runs MUCH slower
> than outbound, very noticeable with FTP.

Classic symptom of 'plex disagreement.

Quote:

> It appears the line runs only half duplex. The network guys says the switch is
> set for full duplex, but runs in half because the E10 requests it.

> On the E10, I see the follwing, as I can understand from the manual. I have
> not done much work with these settings, so I may miss something here.

> It is set to do full duplex:
>   # ndd /dev/hme 10fdx_cap
>   1

No, that means it is CAPable of 10Mbit full-duplex.

Quote:

> No negotiation
>   # ndd /dev/hme adv_autoneg_cap
>   0

You have turned off negotiation, so all of the lp* and adv*
parameters will mean nothing.

Quote:> But it thinks the Link Partner (the switch, I presume) can not do
> full duplex:

>   # ndd /dev/hme lp_10fdx_cap
>   0

Meaningless when adv_autoneg_cap == 0.

Quote:> But it reports it is doing full duplex.

>   # ndd /dev/hme link_mode
>   1

> (I assume '1' means full, the manual is not real clear on that)

Correct.

Quote:> And it's set to only do full duplex.
>   # ndd /dev/hme adv_10fdx_cap
>   1
>   # ndd /dev/hme adv_10hdx_cap
>   0

Meaningless when adv_autoneg_cap == 0.
"adv" means ADVertise to the link partner during negotiation.

Look for "late collision" complaints in /var/adm/messages.
That is proof of 'plex problems.

I have never seen a problem with Suns auto-negotiating with
switches, EXCEPT when a network guy set the switch to NOT
negotiate and didn't bother to tell me.  If the link partner
won't negotiate, Solaris will go to half-duplex.  If the
switch is doing full-duplex, you will have symptoms such
as you describe.

My advice is to let Solaris use the defaults, UNLESS the
switch has been set to NOT negotiate, then you will need
to set it to agree with the switch.

You might find this useful:

  http://www.dimensional.com/~ryoder/fast-ethernet.sh

You need to be root to run it.  It makes querying hme/qfe
devices simpler.

ry
--

"Unix:  The Solution to the W2K Problem."

 
 
 

half-duplex/full-duplex problem

Post by Rich Tee » Mon, 06 Mar 2000 04:00:00




> > I have a new Sun E10, that is connected to a network switch using a cat 3
> > cable. We had some problems getting the conenction to work, apparently the
> > machine and the switch could not agree on what speed to run at, so I have
> > manually set it to 10 MB.

> That is very strange;  I've never seen a Sun require manual
> setting of the speed.

Note that S* said that he's using CAT 3 cable, not CAT 5.  CAT 3 isn't
rated for 100 baseT Ethernet: you need CAT 5 for that.

--
Rich Teer

NT tries to do almost everything UNIX does, but fails - miserably.

The use of Windoze cripples the mind; its use should, therefore, be
regarded as a criminal offence.  (With apologies to Edsger W. Dijkstra)

If it ain't analogue, it ain't music.

Voice: +1 (250) 763-6205
WWW: www.rite-group.com

 
 
 

half-duplex/full-duplex problem

Post by Frederic Ponci » Wed, 08 Mar 2000 04:00:00


It seems I'm not alone (see the comp.dcom.sys.cisco thread)

Subject: 100TX speed auto-negotiation

E10 + qfe + cat3 + cisco switch in 10/half = don't work

--
Frdric Poncin


> I have a new Sun E10, that is connected to a network switch using a cat 3
> cable. We had some problems getting the conenction to work, apparently the
> machine and the switch could not agree on what speed to run at, so I have
> manually set it to 10 MB.

> However, I have noticed another problem, incoming traffic runs MUCH slower
> than outbound, very noticeable with FTP.

> It appears the line runs only half duplex. The network guys says the switch is
> set for full duplex, but runs in half because the E10 requests it.

> On the E10, I see the follwing, as I can understand from the manual. I have
> not done much work with these settings, so I may miss something here.

> It is set to do full duplex:
>   # ndd /dev/hme 10fdx_cap
>   1

> No negotiation
>   # ndd /dev/hme adv_autoneg_cap
>   0

> But it thinks the Link Partner (the switch, I presume) can not do
> full duplex:

>   # ndd /dev/hme lp_10fdx_cap
>   0

> But it reports it is doing full duplex.

>   # ndd /dev/hme link_mode
>   1

> (I assume '1' means full, the manual is not real clear on that)

> And it's set to only do full duplex.
>   # ndd /dev/hme adv_10fdx_cap
>   1
>   # ndd /dev/hme adv_10hdx_cap
>   0

> Suggestions?

> Thanks

 
 
 

half-duplex/full-duplex problem

Post by Robert Yode » Wed, 08 Mar 2000 04:00:00





> > > I have a new Sun E10, that is connected to a network switch using a cat 3
> > > cable. We had some problems getting the conenction to work, apparently the
> > > machine and the switch could not agree on what speed to run at, so I have
> > > manually set it to 10 MB.

> > That is very strange;  I've never seen a Sun require manual
> > setting of the speed.

> Note that S* said that he's using CAT 3 cable, not CAT 5.  CAT 3 isn't
> rated for 100 baseT Ethernet: you need CAT 5 for that.

I overlooked the Cat 3 note.

For the information of all, I looked up some of my old notes
on this issue.  I have found these Sun docs on it:

Infodoc 16144
Infodoc 16728
Infodoc 16017
Infodoc 16070
Infodoc 17416

Also, there are 3 ways to force hme/qfe interfaces to
something other than default behaviour:

1. Edit /etc/system.

2. Create a /kernel/drv/hme.conf file.
   ("man hme" and "man driver.conf")

3. Create /etc/init.d/<whatever> and link it to
   /etc/rc2.d/S<whatever>

ry
--

"Unix:  The Solution to the W2K Problem."

 
 
 

1. full-duplex / half-duplex switching, why?

i have rh 8.0 router with iptables and two nic's
eth0 is for local and eth1 for public network.

i can notice in messages something like this:
kernel: eth1: Setting half-duplex on MII #1 link partner capatibility
of 000
kernel: eth1: Setting full-duplex on MII #1 link partner capatibility
of 41e1

it happens more times per day, switching to half-duplex and then back
to full-duplex few minutes later.
why is that?

regards

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