slow ethernet interface

From: Luke Liu <Luke.Liu_at_oryx-usa.com>
Date: Thu, 09 Jul 1998 14:28:57 -0500

I have a network performance problem, do not know if this is a hardware
problem or a setup problem, or if the problem is even on the Dec side.
Would appreciate any help to resolve this issue.

I am bothered by the slowness, the apparent asymmetric behaviour of ping.
I am also wondering why netstat does not report any error while there is a
high percentage of packets loss reported by ping.
 
ges3 is an ALPHAserver 4100 running DU4.0d and ges-pc is a pc running
pcnfs and DOS. I have set ges3 as gateway for ges-pc for the rest of our world.
They are connected via a 100BaseT hub, no other system is connect
to this hub. All the equipments are less than 6 month old, and running
fine otherwise. The following tests is done when there is little load on ges3.
 
ges3> uerf -R |pg
   ......
                                         tu0: DECchip 21140: Revision: 2.0
                                        tu0: auto negotiation capable device
                                        tu0 at pci0 slot 3
                                        tu0: DEC TULIP (10/100) Ethernet
                                         _Interface, hardware address:
                                         _00-00-F8-1F-A5-D1
                                        tu0: auto negotiation off: selecting
                                         _100BaseTX (UTP) port: half duplex
   ......
 
ges3> ping ges-pc
64 bytes from 192.168.2.7: icmp_seq=785 ttl=64 time=22 ms
64 bytes from 192.168.2.7: icmp_seq=786 ttl=64 time=11 ms
64 bytes from 192.168.2.7: icmp_seq=787 ttl=64 time=54 ms
64 bytes from 192.168.2.7: icmp_seq=729 ttl=64 time=49 ms
64 bytes from 192.168.2.7: icmp_seq=730 ttl=64 time=37 ms
64 bytes from 192.168.2.7: icmp_seq=732 ttl=64 time=14 ms
64 bytes from 192.168.2.7: icmp_seq=733 ttl=64 time=3 ms
   ......
 
ges3> netstat -I tu0 1
 packets errs packets errs colls packets errs packets errs colls
 4082440 52 4099970 46 2 71980850 52 73216651 46 2
       1 0 1 0 0 4 0 4 0 0
      1 0 1 0 0 4 0 4 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
      1 0 1 0 0 3 0 3 0 0
   ......
In th mean time, I can ping from ges-pc to any other system, the
response time is always 0 ms, except occasionally, there is a delay of 58 ms.
While this is going on, netstat on ges3 showed:
   ......
       1 0 1 0 0 4 0 4 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
     138 0 138 0 0 277 0 277 0 0
       0 0 1 0 0 1 0 2 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
     139 0 139 0 0 279 0 279 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
       1 0 1 0 0 3 0 3 0 0
     139 0 139 0 0 279 0 279 0 0
       1 0 1 0 0 3 0 3 0 0
   ......
ges3> (cntl-C to the ping process)
 
   ......
 ----ges-pc PING Statistics----
3575 packets transmitted, 3016 packets received, 15% packet loss
round-trip (ms) min/avg/max = 0/28/868 ms
Received on Thu Jul 09 1998 - 21:30:31 NZST

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