3C590: no collisions?

3C590: no collisions?

Post by Jose M. Alcaid » Fri, 13 Jun 1997 04:00:00



Curiously, "netstat -i" _always_ shows 0 collisions on the vx0
ethernet interface (3COM 590, FreeBSD 2.2.1). However, other hosts
attached to the same (saturated) segment have about 5% collision rate.
I suspect that the vx driver does not increment the collision
counter. A colleague has another FreeBSD box with a 3C900 (also
vx driver), and it also shows 0 collisions. Isn't surprising?

--JM
------------------------------------------------------------------------

Universidad del Pais Vasco              | WWW:
Dpto. de Electricidad y Electronica     |  http://www.we.lc.ehu.es/~jose
Facultad de Ciencias - Campus de Lejona | Phone:  +34-4-4647700 x2624
48940 Lejona (Vizcaya) - SPAIN          | Fax:    +34-4-4858139
------------------------------------------------------------------------

 
 
 

3C590: no collisions?

Post by A. Karl Hell » Fri, 13 Jun 1997 04:00:00



: Curiously, "netstat -i" _always_ shows 0 collisions on the vx0
: ethernet interface (3COM 590, FreeBSD 2.2.1). However, other hosts
: attached to the same (saturated) segment have about 5% collision rate.
: I suspect that the vx driver does not increment the collision
: counter. A colleague has another FreeBSD box with a 3C900 (also
: vx driver), and it also shows 0 collisions. Isn't surprising?

 VX on 2.1.5:

Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs  Coll
vx0   1500  <Link>00.a0.24.de.dc.83       128333705    33 120342519   922  1853

: --JM
: ------------------------------------------------------------------------

: Universidad del Pais Vasco              | WWW:
: Dpto. de Electricidad y Electronica     |  http://www.we.lc.ehu.es/~jose
: Facultad de Ciencias - Campus de Lejona | Phone:  +34-4-4647700 x2624
: 48940 Lejona (Vizcaya) - SPAIN          | Fax:    +34-4-4858139
: ------------------------------------------------------------------------

 
 
 

3C590: no collisions?

Post by Jose M. Alcaid » Sat, 14 Jun 1997 04:00:00


<HTML>

<BR><TT>: Curiously, "netstat -i" _always_ shows 0 collisions on the vx0</TT>
<BR><TT>: ethernet interface (3COM 590, FreeBSD 2.2.1). However, other
hosts</TT>
<BR><TT>: attached to the same (saturated) segment have about 5% collision
rate.</TT>
<BR><TT>: I suspect that the vx driver does not increment the collision</TT>
<BR><TT>: counter. A colleague has another FreeBSD box with a 3C900 (also</TT>
<BR><TT>: vx driver), and it also shows 0 collisions. Isn't surprising?</TT><TT></TT>

<P><TT>&nbsp;VX on 2.1.5:</TT><TT></TT>

<P><TT>Name&nbsp; Mtu&nbsp;&nbsp; Network&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Address&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Ipkts Ierrs&nbsp;&nbsp;&nbsp; Opkts Oerrs&nbsp; Coll</TT>
<BR><TT>vx0&nbsp;&nbsp; 1500&nbsp; &lt;Link>00.a0.24.de.dc.83&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
128333705&nbsp;&nbsp;&nbsp; 33 120342519&nbsp;&nbsp; 922&nbsp; 1853</TT>
<BR><TT></TT></BLOCKQUOTE>
<TT>Perhaps the 2.2.1's vx is broken? Here is my "netstat -i" ouput:</TT><TT></TT>

<P><TT>Name&nbsp; Mtu&nbsp;&nbsp; Network&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Address&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Ipkts Ierrs&nbsp;&nbsp;&nbsp; Opkts Oerrs&nbsp; Coll</TT>
<BR><TT>vx0&nbsp;&nbsp; 1500&nbsp; &lt;Link>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
00.60.97.90.3e.db&nbsp; 4022741&nbsp;&nbsp;&nbsp; 31&nbsp;&nbsp; 221483&nbsp;&nbsp;&nbsp;&nbsp;
0&nbsp;&nbsp;&nbsp;&nbsp; 0</TT>
<BR><BR>
<TT>-- JM<BR>
------------------------------------------------------------------------<BR>
Jose M. Alcaide&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

Universidad del Pais Vasco&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| WWW:<BR>
Dpto. de Electricidad y Electronica&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp; <A HREF="http://www.we.lc.ehu.es/~jose">http://www.we.lc.ehu.es/~jose</A><BR>
Facultad de Ciencias - Campus de Lejona | Phone:&nbsp; +34-4-4647700 x2624<BR>
48940 Lejona (Vizcaya) - SPAIN&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| Fax:&nbsp;&nbsp;&nbsp; +34-4-4858139<BR>
------------------------------------------------------------------------</TT>
<BR><TT></TT></HTML>

 
 
 

3C590: no collisions?

Post by Jose M. Alcaid » Sat, 14 Jun 1997 04:00:00


<HTML>

<BR><TT>: Curiously, "netstat -i" _always_ shows 0 collisions on the vx0</TT>
<BR><TT>: ethernet interface (3COM 590, FreeBSD 2.2.1). However, other
hosts</TT>
<BR><TT>: attached to the same (saturated) segment have about 5% collision
rate.</TT>
<BR><TT>: I suspect that the vx driver does not increment the collision</TT>
<BR><TT>: counter. A colleague has another FreeBSD box with a 3C900 (also</TT>
<BR><TT>: vx driver), and it also shows 0 collisions. Isn't surprising?</TT>

<P><TT>&nbsp;VX on 2.1.5:</TT>

<P><TT>Name&nbsp; Mtu&nbsp;&nbsp; Network&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Address&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Ipkts Ierrs&nbsp;&nbsp;&nbsp; Opkts Oerrs&nbsp; Coll</TT>
<BR><TT>vx0&nbsp;&nbsp; 1500&nbsp; &lt;Link>00.a0.24.de.dc.83&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
128333705&nbsp;&nbsp;&nbsp; 33 120342519&nbsp;&nbsp; 922&nbsp; 1853</TT></BLOCKQUOTE>
<TT>Perhaps the 2.2.1's vx is broken? Here is my "netstat -i" ouput:</TT>

<P><TT>Name&nbsp; Mtu&nbsp;&nbsp; Network&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Address&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Ipkts Ierrs&nbsp;&nbsp;&nbsp; Opkts Oerrs&nbsp; Coll</TT>
<BR><TT>vx0&nbsp;&nbsp; 1500&nbsp; &lt;Link>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
00.60.97.90.3e.db&nbsp; 4022741&nbsp;&nbsp;&nbsp; 31&nbsp;&nbsp; 221483&nbsp;&nbsp;&nbsp;&nbsp;
0&nbsp;&nbsp;&nbsp;&nbsp; 0</TT>

<P><TT>-- JM</TT>
<BR><TT>------------------------------------------------------------------------</TT>
<BR><TT>Jose M. Alcaide&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

<BR><TT>Universidad del Pais Vasco&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| WWW:</TT>
<BR><TT>Dpto. de Electricidad y Electronica&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;
<A HREF="http://www.we.lc.ehu.es/~jose">http://www.we.lc.ehu.es/~jose</A></TT>
<BR><TT>Facultad de Ciencias - Campus de Lejona | Phone:&nbsp; +34-4-4647700
x2624</TT>
<BR><TT>48940 Lejona (Vizcaya) - SPAIN&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| Fax:&nbsp;&nbsp;&nbsp; +34-4-4858139</TT>
<BR><TT>------------------------------------------------------------------------</TT></HTML>

 
 
 

3C590: no collisions?

Post by Jose M. Alcaid » Sat, 14 Jun 1997 04:00:00


Please accept my apologies for sending the last message twice and
in HTML format. I was using the new Netsape 4.0, and it defaults
to HTML for posting. Of course, I trashed NS4.0 and went back
to NS3.01.

--JM

 
 
 

3C590: no collisions?

Post by Jose M. Alcaid » Sat, 14 Jun 1997 04:00:00


[ REPOST IN RAW TEXT FORMAT ]



> : Curiously, "netstat -i" _always_ shows 0 collisions on the vx0
> : ethernet interface (3COM 590, FreeBSD 2.2.1). However, other hosts
> : attached to the same (saturated) segment have about 5% collision rate.
> : I suspect that the vx driver does not increment the collision
> : counter. A colleague has another FreeBSD box with a 3C900 (also
> : vx driver), and it also shows 0 collisions. Isn't surprising?

>  VX on 2.1.5:

> Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs  Coll
> vx0   1500  <Link>00.a0.24.de.dc.83       128333705    33 120342519   922  1853

Perhaps the 2.2.1's vx is broken? Here is my "netstat -i" ouput:

Name Mtu  Network Address           Ipkts Ierrs  Opkts Oerrs  Coll
vx0  1500 <Link>  00.60.97.90.3e.db 4022741 31   221483  0     0

--
------------------------------------------------------------------------

Universidad del Pais Vasco              | WWW:
Dpto. de Electricidad y Electronica     |  http://www.we.lc.ehu.es/~jose
Facultad de Ciencias - Campus de Lejona | Phone:  +34-4-4647700 x2624
48940 Lejona (Vizcaya) - SPAIN          | Fax:    +34-4-4858139
------------------------------------------------------------------------

 
 
 

3C590: no collisions?

Post by HAMADA Nao » Mon, 16 Jun 1997 04:00:00




Quote:>Curiously, "netstat -i" _always_ shows 0 collisions on the vx0
>ethernet interface (3COM 590, FreeBSD 2.2.1). However, other hosts
>attached to the same (saturated) segment have about 5% collision rate.
>I suspect that the vx driver does not increment the collision
>counter. A colleague has another FreeBSD box with a 3C900 (also
>vx driver), and it also shows 0 collisions. Isn't surprising?

3COM's Etherlink III and later cards are so intelligent that they deal
with collisions automatically without reporting to the host. Instead
they have statistic registers, which are ignored by the drivers for
now.

- nao

 
 
 

3C590: no collisions?

Post by Jose M. Alcaid » Tue, 17 Jun 1997 04:00:00



> 3COM's Etherlink III and later cards are so intelligent that they deal
> with collisions automatically without reporting to the host. Instead
> they have statistic registers, which are ignored by the drivers for
> now.

Thanks for your explanation. I read the vx man page, but it does
not tell anything about that.

--JM

 
 
 

1. SE toolkit collision stats vs. wire collision stats

I'm running Adrian's performance toolkit from www.sun.com and it is
showing that there are a high number of collisions on the network
interface (according to the stats, up to 15% of network traffic). However,
running a network analyzer on the wire shows that we have about 10-15%
utilization at most, and pretty close to zero ethernet collisions. So,
what exactly are the collisions being shown?

On a similar vein, the retransmission statistics for the host are very
high (often >60%) and implementing one of the suggested tuning variables
made by the toolkit - which was to increase the tcp_rexmit_interval_min
from 200 to 1500 - resulted in a dramatic performance reduction -
transfer rates over a T1 WAN link dropped to about 5% of the available
capacity.

Any info would be appreciated. Thanks in advance.
Daniel.

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