Net Manager not load balancing

Hi

Does anyone know how to get the QNX 4 Net Manager to load balance traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

On Thu, 12 Apr 2001 21:29:07 -0500, “scott krekling”
<sr.krek@worldnet.att.net> wrote:


I personnaly know of no option to control this.

Dual lan on QNX4 is IMO only usefull for redudancies.
A few years ago a friend a mine try dual lan to improve
thoughput, apparently it didn’t help at all.



Hi

Does anyone know how to get the QNX 4 Net Manager to load balance traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

Nearly all my QNX nodes are dual ethernet. In my experience, the QNX4 Net
manager ALWAYS load balances. Are you sure you do not have a setup or
hardware problem?
As far as improved throughput, I have never measured it, but I cannot
believe it does not provide some increased bandwidth.

scott krekling <sr.krek@worldnet.att.net> wrote in message
news:9b5o2c$dr7$1@inn.qnx.com

Hi

Does anyone know how to get the QNX 4 Net Manager to load balance traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is
Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

Dual LAN’s do improve throughput; however, it is difficult to measure,
and certainly can’t be measured by just one virtual circuit using
send/receive/reply. In order to verify that load balancing does indeed
work, you need to create a reply driven server with lots of clients
(since you need to “fill up” the media to see the load balancing
starting to work - i.e. Net will only get to the point where it is
transmitting 2 different packets simultaneously over the two lans when
it has a sufficient amount of packets in the queue that it can fill up
one pipe). If you create a test app like the one described, you will
see that the aggregate throughput between all clients and the server
will exceed the bandwidth of one of the lan links (thus verifying that
load-balancing really does occur). I have done this; note, however,
that 2 lans will not give you double the throughput - I have found that
175% of the throughput of a single lan can be achieved on modest
hardware.

From a real-time perspective load-balancing is a bit of a white
elephant. I think the Qnet approach of real redundancy (simultaneously
txing 2 identical packets), is much more appropriate for distributed
real-time systems (since worst case transmission time remains identical
when a link fails - this is not the case with QNX4).

-----Original Message-----
From: mcharest@nozinformatic.com (Mario Charest)
[mailto:mcharest@nozinformatic.com]
Posted At: Friday, April 13, 2001 7:01 AM
Posted To: qnx4
Conversation: Net Manager not load balancing
Subject: Re: Net Manager not load balancing


On Thu, 12 Apr 2001 21:29:07 -0500, “scott krekling”
<sr.krek@worldnet.att.net> wrote:


I personnaly know of no option to control this.

Dual lan on QNX4 is IMO only usefull for redudancies.
A few years ago a friend a mine try dual lan to improve
thoughput, apparently it didn’t help at all.



Hi

Does anyone know how to get the QNX 4 Net Manager to load balance
traffic
between two ethernet networks? It fails over to either network for
fault
tolerance fine, but i see no load balancing for better throughput. OS
is Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip
drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

One pitfall not mentioned is that if your lan pipes are not of equal
size, QNET will lean heavily on the larger one.



Previously, scott krekling wrote in qdn.public.qnx4:

Hi

Does anyone know how to get the QNX 4 Net Manager to load balance traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.
\


Mitchell Schoenbrun --------- maschoen@pobox.com

Mitchell Schoenbrun <maschoen@pobox.com> wrote in message
news:Voyager.010417115405.26201C@node1…

One pitfall not mentioned is that if your lan pipes are not of equal
size, QNET will lean heavily on the larger one.

I’m not sure, but I think you can change this by changing the “advertised
media rate” in the driver.

Previously, scott krekling wrote in qdn.public.qnx4:
Hi

Does anyone know how to get the QNX 4 Net Manager to load balance
traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is
Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.



\

Mitchell Schoenbrun --------- > maschoen@pobox.com

Rennie Allen <RAllen@csical.com> wrote in message
news:D4907B331846D31198090050046F80C903CF7B@exchangecal.hq.csical.com

Dual LAN’s do improve throughput; however, it is difficult to measure,
and certainly can’t be measured by just one virtual circuit using
send/receive/reply. In order to verify that load balancing does indeed
work, you need to create a reply driven server with lots of clients
(since you need to “fill up” the media to see the load balancing
starting to work - i.e. Net will only get to the point where it is
transmitting 2 different packets simultaneously over the two lans when
it has a sufficient amount of packets in the queue that it can fill up
one pipe). If you create a test app like the one described, you will
see that the aggregate throughput between all clients and the server
will exceed the bandwidth of one of the lan links (thus verifying that
load-balancing really does occur). I have done this; note, however,
that 2 lans will not give you double the throughput - I have found that
175% of the throughput of a single lan can be achieved on modest
hardware.

From a real-time perspective load-balancing is a bit of a white
elephant. I think the Qnet approach of real redundancy (simultaneously
txing 2 identical packets), is much more appropriate for distributed
real-time systems (since worst case transmission time remains identical
when a link fails - this is not the case with QNX4).

I agree that the redundancy options in QNet are nicer. If anyone from QSSL
is listening, what are the chances (if any) of this flexibility showing up
in QNX4 networking?

-----Original Message-----
From: > mcharest@nozinformatic.com > (Mario Charest)
[mailto:> mcharest@nozinformatic.com> ]
Posted At: Friday, April 13, 2001 7:01 AM
Posted To: qnx4
Conversation: Net Manager not load balancing
Subject: Re: Net Manager not load balancing


On Thu, 12 Apr 2001 21:29:07 -0500, “scott krekling”
sr.krek@worldnet.att.net> > wrote:


I personnaly know of no option to control this.

Dual lan on QNX4 is IMO only usefull for redudancies.
A few years ago a friend a mine try dual lan to improve
thoughput, apparently it didn’t help at all.



Hi

Does anyone know how to get the QNX 4 Net Manager to load balance
traffic
between two ethernet networks? It fails over to either network for
fault
tolerance fine, but i see no load balancing for better throughput. OS
is Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip
drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

My experience is that unless the media rate is 10 times faster they are
comsidered the same.

If one IS considered faster Net will use it as long as it is up.

If they are considered the same it will use the one with the shorter TX
queue.


Bill Caroselli - Sattel Global Networks
1-818-709-6201 ext 122



“Stephen Thomas” <slthomas@corpDOTolin.com> wrote in message
news:9bist4$7gg$1@inn.qnx.com

Mitchell Schoenbrun <> maschoen@pobox.com> > wrote in message
news:Voyager.010417115405.26201C@node1…
One pitfall not mentioned is that if your lan pipes are not of equal
size, QNET will lean heavily on the larger one.


I’m not sure, but I think you can change this by changing the “advertised
media rate” in the driver.



Previously, scott krekling wrote in qdn.public.qnx4:
Hi

Does anyone know how to get the QNX 4 Net Manager to load balance
traffic
between two ethernet networks? It fails over to either network for
fault
tolerance fine, but i see no load balancing for better throughput. OS
is
Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip
drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.



\

Mitchell Schoenbrun --------- > maschoen@pobox.com

\

As Rennie has pointed out, you won’t see any performance improvement with a
single pair of processes doing Send/Receive/Reply across the network. The
QNX 4 Net manager does not break up a message to send parts of it over
separate LANs at the same time. In order to see a performance increase, you
have to run two or more pairs of processes communicating across the network
at the same time. If your CPU is fast enough, you can get very nearly
double the throughput with dual 10BT LANs. With 100TX, it’s tough for the
CPU/memory/bus to keep up with the data rate, so you won’t get as close to
doubling throughput.


Bert Menkveld
Engineer
Corman Technologies Inc.

“Mario Charest” <mcharest@nozinformatic.com> wrote in message
news:3ad7059f.2017941@inn.qnx.com

On Thu, 12 Apr 2001 21:29:07 -0500, “scott krekling”
sr.krek@worldnet.att.net> > wrote:


I personnaly know of no option to control this.

Dual lan on QNX4 is IMO only usefull for redudancies.
A few years ago a friend a mine try dual lan to improve
thoughput, apparently it didn’t help at all.



Hi

Does anyone know how to get the QNX 4 Net Manager to load balance traffic
between two ethernet networks? It fails over to either network for fault
tolerance fine, but i see no load balancing for better throughput. OS is
Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.

Bill Caroselli <Bill@sattel.com> wrote:

My experience is that unless the media rate is 10 times faster they are
comsidered the same.

If one IS considered faster Net will use it as long as it is up.

If they are considered the same it will use the one with the shorter TX
queue.

In QNET, “which lan to use” is decided by “cost”. Cost is caculated
by the media rate, how heavy the lan is, and how many errors (retransmit)
the lan have. Of cause, the “media rate” have the largest weight.

-xtang



Bill Caroselli - Sattel Global Networks
1-818-709-6201 ext 122



“Stephen Thomas” <> slthomas@corpDOTolin.com> > wrote in message
news:9bist4$7gg$> 1@inn.qnx.com> …
Mitchell Schoenbrun <> maschoen@pobox.com> > wrote in message
news:Voyager.010417115405.26201C@node1…
One pitfall not mentioned is that if your lan pipes are not of equal
size, QNET will lean heavily on the larger one.


I’m not sure, but I think you can change this by changing the “advertised
media rate” in the driver.



Previously, scott krekling wrote in qdn.public.qnx4:
Hi

Does anyone know how to get the QNX 4 Net Manager to load balance
traffic
between two ethernet networks? It fails over to either network for
fault
tolerance fine, but i see no load balancing for better throughput. OS
is
Qnx
4.25J running on compaq ml350 servers.

Lan 1 consists of two corman fast ethernet cards using Net.tulip
drivers
with a netgear 10/100base T hub.

Lan 2 consists of two compaq feature boards w/ ethernet port using
Net.ether82557 drivers.

Thanks for any help you can give.



\

Mitchell Schoenbrun --------- > maschoen@pobox.com

\

OK. I thought we were talking about QNX 4. This is a QNX 4 NG.


Bill Caroselli - Sattel Global Networks
1-818-709-6201 ext 122



“Xiaodan Tang” <xtang@qnx.com> wrote in message
news:9bk7t0$2na$2@nntp.qnx.com

In QNET, “which lan to use” is decided by “cost”. Cost is caculated
by the media rate, how heavy the lan is, and how many errors (retransmit)
the lan have. Of cause, the “media rate” have the largest weight.

Bill Caroselli <Bill@sattel.com> wrote:

My experience is that unless the media rate is 10 times faster they are
comsidered the same.

If one IS considered faster Net will use it as long as it is up.

If they are considered the same it will use the one with the shorter TX
queue.


Bill Caroselli - Sattel Global Networks
1-818-709-6201 ext 122



“Stephen Thomas” <> slthomas@corpDOTolin.com> > wrote in message
news:9bist4$7gg$> 1@inn.qnx.com> …
Mitchell Schoenbrun <> maschoen@pobox.com> > wrote in message
news:Voyager.010417115405.26201C@node1…
One pitfall not mentioned is that if your lan pipes are not of equal
size, QNET will lean heavily on the larger one.


I’m not sure, but I think you can change this by changing the “advertised
media rate” in the driver.

For what it’s worth, I posted this little bit of information in my
initial post on the topic.

The actual multiplier is 8 – if one is more than 8 times faster than
the other, the slow one won’t be used. And, yes, it does look at the
“advertised bit rate” as per Net.driver -r option.

-David


QNX Training Services
dagibbs@qnx.com