ethernet hardware question

Skybuck Flying wrote:
I have two computers connected to each other via 10 megabit ethernet cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Depends whether they are running full duplex mode. Have you made sure
both NIC's are set to the same setting and they are not relying on auto
negotiation?

I have two computers connected to each other via 10 megabit ethernet cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive anything
anymore...

Something like that I am not 100% sure.

I have two computers connected to each other via 10 megabit ethernet cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive
anything
anymore...

Something like that I am not 100% sure.


As the other poster said duplex mode dictates that. On the other hand, UDP
is by nature an unreliable protocol so you can't expect all of the packets
to reach their destination in a context where all those packets are
important to the communication at hand.

A host sending to a much slower host is one of the situations where there
will be high packet loss if the packets have no gap between each other.

Alex.

On Mon, 20 Oct 2003 16:00:15 +0200, "Skybuck Flying" wrote:

I have two computers connected to each other via 10 megabit ethernet cards
and UTP cross over cable.

My question is the following about ethernet :

You really should be asking in comp.dcom.ethernet, as your questions don't have
anything to do with TCP/IP, and have everything to do with ethernet data
communications.


[snip]
--
Lew Pitcher
IT Consultant, Enterprise Technology Solutions
Toronto Dominion Bank Financial Group

(Opinions expressed are my own, not my employers')

"Sin" wrote in message
...
I have two computers connected to each other via 10 megabit ethernet
cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with
winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp
packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive
anything
anymore...

Something like that I am not 100% sure.


As the other poster said duplex mode dictates that. On the other hand, UDP
is by nature an unreliable protocol so you can't expect all of the packets
to reach their destination in a context where all those packets are
important to the communication at hand.

A host sending to a much slower host is one of the situations where there
will be high packet loss if the packets have no gap between each other.

Hmm.. very interesting... I wonder what the formula would be for calculating
the right gap time ?!


Alex.

"Someone Somewhere" wrote in message
...
Skybuck Flying wrote:
I have two computers connected to each other via 10 megabit ethernet
cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Depends whether they are running full duplex mode. Have you made sure
both NIC's are set to the same setting and they are not relying on auto
negotiation?

Well... I am not sure... they are pretty old cards... I got a few cards for
free too without software.

For one of the card I might have some old dos software to configure them...

Could it be possible to configure them from windows ???

Hmm.. very interesting... I wonder what the formula would be for calculating
the right gap time ?!

The round trip time of the slower host, but this of course can be
increased a lot depending on the processing needed on that packet.
What I'm trying to say is it makes a huge difference if you simply
send the packet and the remote host can either trash it or is fast
enough to completly process it before the next one arrives. With an
ongoing sustained stream of packets it's obvious that there will be
lost packets if the receiving host can't keep up with processing, but
otherwise would be fast enough on the ethernet level alone.

TCP does a lot of optimisations (congestion control) to actually
minimize packet loss (and hence retransmits) as much as possible.
Another thing to mention is that UDP packets of 512 Bytes are non
standard. So, if what you intend to do should be useable in a just a
little wider area I think you should considder switching to TCP.

Just my 2¢ though.

Markus

"Skybuck Flying" wrote in message
...

"Sin" wrote in message
...
I have two computers connected to each other via 10 megabit ethernet
cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with
winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp
packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive
anything
anymore...

Something like that I am not 100% sure.


As the other poster said duplex mode dictates that. On the other hand,
UDP
is by nature an unreliable protocol so you can't expect all of the
packets
to reach their destination in a context where all those packets are
important to the communication at hand.

A host sending to a much slower host is one of the situations where
there
will be high packet loss if the packets have no gap between each other.

Hmm.. very interesting... I wonder what the formula would be for
calculating
the right gap time ?!

This document mentions a gap time of 9 microseconds (?)

http://www.lap.ttu.ee/erki/failid/ko...1/lap3731_loen
gukiled_lan.pdf

"Skybuck Flying" wrote in message
...

"Sin" wrote in message
...
I have two computers connected to each other via 10 megabit ethernet
cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with
winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp
packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive
anything
anymore...

Something like that I am not 100% sure.


As the other poster said duplex mode dictates that. On the other hand,
UDP
is by nature an unreliable protocol so you can't expect all of the
packets
to reach their destination in a context where all those packets are
important to the communication at hand.

A host sending to a much slower host is one of the situations where
there
will be high packet loss if the packets have no gap between each other.

Hmm.. very interesting... I wonder what the formula would be for
calculating
the right gap time ?!

This document also mentions some interesting times, to bad it's in italian
lol:

http://www.fis.unipr.it/lca/Corsi/et.../ethernet.html

"Skybuck Flying" wrote in message
...

"Sin" wrote in message
...
I have two computers connected to each other via 10 megabit ethernet
cards
and UTP cross over cable.

My question is the following about ethernet :

Is ethernet able to send and receive packets at the same time ?

Or should each card wait until it's clear to send ?

I'm asking this since I am testing something that has to do with
winsock.

Large udp packets of 64 kb.

If my slow p166 and my fast PIII 450 both start sending large udp
packets
of 64 kilobyte... it seems like the P166 or the P450 can't receive
anything
anymore...

Something like that I am not 100% sure.


As the other poster said duplex mode dictates that. On the other hand,
UDP
is by nature an unreliable protocol so you can't expect all of the
packets
to reach their destination in a context where all those packets are
important to the communication at hand.

A host sending to a much slower host is one of the situations where
there
will be high packet loss if the packets have no gap between each other.

Hmm.. very interesting... I wonder what the formula would be for
calculating
the right gap time ?!

Cooooooll:

http://www.esat.kuleuven.ac.be/~3irt.../C5/analytic_m
odel.html