We have recently developed data transfer programs using QNX TCP/IP and
done a few tests for measuring rate of data transfer on ethernet link.
We have connected two computers on ethernet interface with the help of a
crossover cable. We have not utilised a hub/switch during the experiment.
The hardware configuration of computers is as follows :-
Computer A = 300A Celeron with 32MB SDRAM and 3COM’s (3C905) 10/100
ethernet interface
Computer B = 33MHz 486 with 8MB RAM and 10baseT ethernet interface
1.] The computer A sends establishes TCP/IP connection with computer B which
is waiting for connection request.
2.] Computer A sends a 4-byte query packet to computer B
3.] Computer B on receipt of query packet responds with 60KB data
We could observe that Computer A receives the data response from
computer B nearly 2 to 3 seconds after sending out a 4-byte query packet.
Computer B reads data block from shared memory and writes the data single
function call.
Why should the 60KB data transfer on ethernet link take transfer time in
seconds? Is there any of achieving faster data transfers on 10baseT
ethernet? Does our applications require any optimization? Should we not
expect faster data transfer times on a 10Mbps link? What is introducing this
delay in data transfer?
Can the time of data transfer on an ethernet network (that has multiple
machines connected using a LAN switch) be predicated?
Have you checked your TCP/IP socket settings. I.e., NODELAY? You may have
a buffering problem. Further, do you know that Computer B is transmitting
immediately after receiving the request or is there a process delay?
We have recently developed data transfer programs using QNX TCP/IP and
done a few tests for measuring rate of data transfer on ethernet link.
We have connected two computers on ethernet interface with the help of
a
crossover cable. We have not utilised a hub/switch during the experiment.
The hardware configuration of computers is as follows :-
Computer A = 300A Celeron with 32MB SDRAM and 3COM’s (3C905) 10/100
ethernet interface
Computer B = 33MHz 486 with 8MB RAM and 10baseT ethernet interface
1.] The computer A sends establishes TCP/IP connection with computer B
which
is waiting for connection request.
2.] Computer A sends a 4-byte query packet to computer B
3.] Computer B on receipt of query packet responds with 60KB data
We could observe that Computer A receives the data response from
computer B nearly 2 to 3 seconds after sending out a 4-byte query packet.
Computer B reads data block from shared memory and writes the data single
function call.
Why should the 60KB data transfer on ethernet link take transfer time
in
seconds? Is there any of achieving faster data transfers on 10baseT
ethernet? Does our applications require any optimization? Should we not
expect faster data transfer times on a 10Mbps link? What is introducing
this
delay in data transfer?
Can the time of data transfer on an ethernet network (that has
multiple
machines connected using a LAN switch) be predicated?