FTP gone slow

[Richard Woolley]

Hi anyone had FTP almost get to stopping point?
I can FTP between unix machines on one subnet (FDDI) ok, i can also take files from the machine ok. However when i try and FTP to the machine it sits there pretty much not moving.

Anyone any ideas.

ps. ive already tried /sbin/init.d/net stop;/sbin/init.d/net start
lanscan doesnt show any cards down!

[Clemens van Everdingen]

Hi,

do you see the same difference if you do a ping from or to the machine ?

C.

[Ron Kinner]

I suspect you have a duplex mismatch on the Ethernet.

Go into lanadmin
lan
display
see if you are getting a lot of errors or collisions.

It is common for autonegotiate to fail. When this happens transmission in one direction (from the full duplex end) works fine but transmission from the other end suffers because the NIC detects a lot of what it thinks are collisions, then stops, waits the random back off time and retransmits.

The solution is to hard program the same speed and duplex on both the PC AND the switch.

Ron

[Richard Woolley]

a ping shows no difference,
but the inbound discards and errors go up when i try an ftp xfer.

so i will see if i can set the switch end to not autonegotiate but stay at 100Mbps.

[Ron Kinner]

Sounds like the switch is running at half duplex. That causes it to generate a lot of erros since it is required to stop transmitting as soon as it sees something else on the LAN and that leaves a lot of too short and incomplete packets which the PC sees as incoming errors.

Make sure you lock both ends to 100 full. Otherwise the next time you reboot or just unplug the NIC cable you may have the same problem in the reverse direction.

Ron

[Darrell Allen]

Hi Mark,

Just to reiterate what others have said, it's the duplex mismatch that's causing the problem. Slow file transfers are classic examples of the problem. Be sure to lock both ends at 100FD.

Though this problem doesn't always occur, I find it best to always force connections for servers to the desired speed and duplex setting. I've simply seen this problem too many times to trust autoneg.

Darrell

[pap]

Hi, you need to check following.

1.HD/FD setting.
2. Auto negotiate setting on switch side as well as on LAN card side (on HP-UX).

-pap

[Roger Baptiste]

hi,

Try something like the following:

:>lanscan
Hardware Station Crd Hdw Net-Interface NM MAC HP-DLPI DLPI
Path Address In# State NamePPA ID Type Support Mjr#
10/4/4 0x080009DAB0F2 0 UP lan0 snap0 1 ETHER Yes 119
10/12/6 0x0060B04ACBD8 1 UP lan1 snap1 2 ETHER Yes 119

:>lanadmin -x 0
Current Speed = 100 Full-Duplex Auto-Negotiation-OFF

Make sure your FULLduplex is ON and autonegotiation oFF. (depending on the switch setting). you can set this by running lanadmin -X command with the appropriate options as per your card. (100FD is one).

HTH
raj

[MANOJ SRIVASTAVA]

Mark

1. Do a lanscan to get the nmid or the ppa no. of the required card .

2. Do landmin -x no to get the current setting

3. Change it to 100FD using lanadmin -X 100FD

if not set ot 100 Full Duplex , If it is set to 100FD then my next bet is to change it to 100HD , in wither case keep the console connected and wait like 10-15 seconds for the settings to take effect.Then FTP will be faster .

I am assuming you have a 100 MBPS interface , to make the settings permanent you need to change in /etc/rc.config.d/hp100baseconf and stop and start the net.


Manoj Srivastava

[Richard Woolley]

thanks for the lanadmin change of settings command, however why do i change the /etc/rc.config.d/hpbase100conf file when i have not needed to before and none of my other machines have these settings?

[Darrell Allen]

Hi Mark,

The assumption is that you did have a duplex mismatch. Did you verify that?

Sometimes the server and switch will negoiate correctly but often they don't. The only way I know to ensure there is no mismatch is to force both ends to the same setting. lanadmin is used to do so "on the fly". The supported method to force the setting at boot time (or when using /sbin/init.d/net) is with the config file in /etc/rc.config.d.

There are a couple of config files for fast ethernet. Use "ioscan -fnkC lan" to determine which driver you have then consult the attached doc to determine which config file to change.

Darrell

[Bill Hassell]

Duplex mismatch is a very common problem with 100 BaseT and the reasons are related to complex timing issues and two major standards to determine speed and duplex. The mismatch can be caused by the length of the cable which is why one machine negotiates OK but another fails.

To be safe (in a productin environment), lock all the machines *AND* the switches to which they connect at 100FD. This will prevent future problems. 100FD wil never have any collisions or FCS errors unless the duplex is mismatched.