Network slow

[david_252]

We are suddenly experincing very slow network connection on nclass 11.0 box. Pl. suggest me where to look into

Thanks

David.

[RAC_1]

check the switch/router settings.

From server side check the spped of nics. if auto-negotiate then check from switch/router side.

[A. Clay Stephenson]

If this is NOT a Gigabit connection which MUST remain in Auto-Negotiate, you should hard set the speed duplex settings on both the host and the switch. You will find that 100Base-T auto-negotiate is not reliable. Surprising, speed-duplex mismatches will continue to work - badly; you might not even notice a problem with telnet or rlogin.

[James R. Ferguson]

Hi David:

You note "slow network connection". Are you running DNS? If so, does making a connection by address versus name differ in speed? If it's faster when using an address you may be suffering from reverse-name-lookup delays. Make sure that your DNS tables contain the names of all devices.

Regards!

...JRF...

[Jeff Schussele]

Hi David,

First thing to do is check current NIC settings - run:

lanadmin -x X

Where X = the lan instance

Then check TCP stats

netstat -ip tcp

you're looking for excessive retransmits & out-of-order receives.
These can indicate mismatched settings between NICs & switches.

Rgds,
Jeff

[david_252]

Hi Jeff:

Thanks. I have attched the output of netstat -ip tcp . Please advise.

Thanks

David.

[Marco Santerre]

Chances are, the slowliness of your network is probably due to a discrepencies between the configuration of your switch port and your lan card.

to check your lan card settings :
lanadmin -x PPA# (PPA# being your lan card number which you can find in lanscan)

To fix your settings online :
lanadmin -X 100FD PPA# (that is if you want to set it to 100 Full Duplex)

And I would also suggest to change your settings in the appropriate file in /etc/rc.config.d for the right lan card.

[Jeff Schussele]

Hi (again),

Although the retran & out-of-order counts aren't excessive, they do point to probable mismatch between NIC & switch.

What does the lanadmin command return?

lanadmin -x 0

IF it's lan0 - use the proper instance number.
Do an
ioscan -fnC lan
If you're not sure of the instance.

Jeff

[david_252]

Hi (again)

We have 5 NIC cards and all of them are set to 100 Full-Duplex Auto-Negotiation-OFF.

Thanks
David.

[david_252]

Hi:
Also when i do lanscan we get two No.s one Crd In# and NM ID. which should be used for lanadmin -x ?

Thanks
David.

[Jeff Schussele]

Since you're HP-UX 11.0 - you use the Crd In # - or instance number.

IF you were 10.2 - you'd use the NMID number.

I now suggest you have your network people check the switch ports & if NOT set to 100FD - Auto_off, have them change it to that & lock them down.

Rgds,
Jeff

[rick jones]

indeed, the netstat -p tcp stats show packet losses (well, they show TCP retransmissions and out of order receipt, which imply packet losses...) However, the rates seem a bit lower than I would expect for a duplex mis-match situation.

I would go ahead and follow the suggestion to check the lanadmin stats. If the description shows the link in full-duplex, a duplex mismatch is suggested by a non-zero and increasing FCS Error count.

If the description shows the interface in half-duplex, then a duplex mismatch is suggested by a non-zero and increasing _late_ collision count.

If you have neither late collisions, nor FCS errors, you do not have a duplex mismatch.

If you start hardcoding, you have to remember to hard-code _EVERYTHING_ EVERYWHERE to the same values. You cannot have one side set for auto and another for full. both sides must be auto or both full or both half (the only exception is you can "get away with" mixing auto and half but don't rely on it...)

[connie miller_1]

i agree with some helpers but i always make sure of all things before the next difficult steps are taken like

1. maintance of the computer.

2. clean cache, temp cookies, AND defrag.

3. check all cables wires etc.

4 call your service provider ask if they have been getting calls on the same problem your having.

5. if they are not then call your phone company or cable company whatever you are using to connect your dsl or dial up with even dsl has to use the line from the phone companys lines or underground cables but your connection to use phone while online is rerouted to have the phone free to talk on or get calls.

6. make sure it isnt the web sites check on the time your connecting to like for example aol has the busy hours in pacfic time between hrs 7pm to 2am every sun to thur. on fri, sat forget it all gets boot all slow even dsl.

7. make sure your speed of your dsl or dialup is configured correctly. you may do this so fast and easy by clicking aol help and click auto repair it does this for you.
if all this fails pls contact the service provider support or your manufacture

this is only my recommendation to check all before digging in tec issues that i find way to tec for me im more or less the internet and pc maintance with knowledge of the ethernet cards and modems and some systems errors not into any lost kern or dll or exe stuff hate all that just when needed a online support quest or speed of system slow responses ok oh 1 more thing if you have aol go to keyword type in SYSTEM RESPONSE click ok the aol takes over and finds the problem if they cant then its your pc ok hope i helped

[KapilRaj]

connie,
r u in a diffrent context ?. I saw another post similiar. sounds diffrent.

kaps

[K.Vijayaragavan.]

netstat -i

From the command output of "netstat -i",
The number of collisions (Coll) divided by the number of output packets (Opkts) is the collision rate. If your collision rate is greater than 10%, consider dividing your network into smaller segments and putting an NFS server on each segment.

[K.Vijayaragavan.]

"netstat -I I/Fname" command too to check the status of each interfaces.

[K.Vijayaragavan.]

Use traceroute command.

This is just a good thing to do as a sanity check. It
could show that packets are taking an unexpected path to or from the server
which could account for the time.