IOS : ttcp

Voici une petite astuce à deux balles. Pour ceux qui voudrait faire un petit test de débit entre un Linux et un routeur Cisco, l’outil ttcp est à là pour vous.
Ne chercher pas à le trouver avec votre copine : la touche “Tab” 😉

nas-cde-madrillet#tt?
% Unrecognized command
nas-cde-madrillet#tt
Néanmoins :

nas-cde-madrillet#ttcp
transmit or receive [receive]:
perform tcp half close [n]:
receive buflen [8192]:
bufalign [16384]:
bufoffset [0]:
port [5001]:
sinkmode [y]:
rcvwndsize [4128]: 6250000
delayed ACK [y]:
show tcp information at end [n]:

ttcp-r: buflen=8192, align=16384/0, port=5001
rcvwndsize=6250000, delayedack=yes  tcp
ttcp-r: accept from 217.169.242.181 (mss 536, sndwnd 5888, rcvwnd 65511)
ttcp-r: 40501272 bytes in 10012 ms (10.012 real seconds) (~3950 kB/s) +++
ttcp-r: 6036 I/O calls
ttcp-r: 0 sleeps (0 ms total) (0 ms average)
nas-cde-madrillet#

Et du côté de ma station Linux :

clucas@pluton:~$ iperf -c nas-cde-madrillet -i 1
------------------------------------------------------------
Client connecting to nas-cde-madrillet, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[  3] local 217.169.242.181 port 41570 connected with 217.169.240.130 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  3.80 MBytes  31.9 Mbits/sec
[  3]  1.0- 2.0 sec  3.82 MBytes  32.0 Mbits/sec
[  3]  2.0- 3.0 sec  3.84 MBytes  32.2 Mbits/sec
[  3]  3.0- 4.0 sec  3.84 MBytes  32.2 Mbits/sec
[  3]  4.0- 5.0 sec  3.85 MBytes  32.3 Mbits/sec
[  3]  5.0- 6.0 sec  3.87 MBytes  32.4 Mbits/sec
[  3]  6.0- 7.0 sec  3.90 MBytes  32.7 Mbits/sec
[  3]  7.0- 8.0 sec  3.84 MBytes  32.2 Mbits/sec
[  3]  8.0- 9.0 sec  3.94 MBytes  33.0 Mbits/sec
[  3]  9.0-10.0 sec  3.93 MBytes  33.0 Mbits/sec
[  3]  0.0-10.0 sec  38.6 MBytes  32.4 Mbits/sec

Si vous ne voulez pas être déçu sur les débits que vous mesurez, je vous conseille de positionner ‘rcvwndsize‘ à :

rcvwndsize = (BW nominale / 8) * delai

avec :
 * BW nominale en bit/s
 * délai en seconde

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