netstat questions!!

[Jonathan Caplette]

Hi guys,

When I run this command: netstat -n -I 3 , it's giving me the packets in and out every 3 sec for the interface, what I wanna know it's if I get, for exemple, 100 for packet in column, what is the size of each packet?? And how do I know if my network card is overloaded (for a 100Mbps)???

Thanks
Jonathan

[Craig Rants · Accepted solution]

Run lanadmin and check the stats out for that specific card. It will give you more info than netstat.

GL,
C

[Sanjay_6]

Hi Jonathan,

A network card is expected to be overloaded if the no of retransmission is very high, the collision is high. also look at this thread,

http://docs.hp.com/hpux/onlinedocs/os/11.0/tuningwp.html#networks

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90701/B2355-90701_top.html&con=/hpux/onlinedocs/B2355-90701/00/00/57-con.html&toc=/hpux/onlinedocs/B2355-90701/00/00/57-toc.html&searchterms=performance%7cnetwork&queryid=20020305-130535

Hope this helps.

Regds

[S.K. Chan]

# netstat -nr
==> at the pmtu column, gives you the packet size being sent and received.

[Ron Kinner]

If you really want to see what is happening on your system run MRTG. It will draw some nice graphs over time which really show how busy your network is.

http://people.ee.ethz.ch/~oetiker/webtools/mrtg/

It's free and not difficult to set up.

If you insist on knowing everything about your packets you might want to look into tcpdump.

http://www.tcpdump.org/

Another great freebie.

By the way, S. K. Cahn, netstat -rn just shows the maximum packet size in the pmtu column. If you are doing a big ftp transfer then you will use lots of maximum sized packets but other protocols such as telnet tend to use much smaller ones. I suppose you can always do a worst case scenario and multiply the # of packets by 1500 bytes/packet times 8 bits/byte to get back to get a rough not-to-exceed estimate of the traffic load in bps.

Ron

[Ron Kinner]

If your HP connects to a reasonably intelligent switch then the switch can tell you the load on the port and some can even break it down into so many of packet size range a, so many of packet size range b ...

Ron

[Michael Tully]

Hi,

If you've got a problem with your 100Mbs
lan NIC it could be to do with having your
card set up as half-duplex. You can see
this using lanadmin and looking at the
number of 'late collisions'. To fix it
you need to make sure that you have the
appropriate patches and that you can change
it to full-duplex on the fly using SAM
or from the command line using
lanadmin -X 100FD 0 (card number)
Also you will need to modify your
/etc/rc.config.d/hpbase100conf file (HPUX11)
to reflect those changes.

HTH
-Michael

[Jonathan Caplette]

Thanks for the hlep guys!!

ciaos!!