topic Re: network collisions in Operating System - Linux

network collisions

BKUMAR — Wed, 11 Sep 2002 16:54:14 GMT

Hi BigBrains

i am getting a n/w collisions on my K320 with 10.20 running on it....when the backup starts from remotely from reel s/w it starts collisions on lan1 and backup s/w gets corruptetd on a remote m/c...i listed some info .....pls guide me to troubleshoot.....Thx in advance

#lanscan

Hardware Station Crd Hardware Net-Interface NM MAC HP DLPI Mjr
Path Address In# State NameUnit State ID Type Support Num
10/4/8.1 0x080009D2EE2F 0 UP lan0 UP 4 ETHER Yes 185
10/4/16 0x080009D62078 2 UP lan2 UP 5 ETHER Yes 75
10/12/6 0x080009D416E1 1 UP lan1 UP 6 ETHER Yes 52

#ioscan -f | grep lan

lanmux 0 10/4/8 lanmux0 CLAIMED INTERFACE HP J2146A - 802.3 LAN
lan 0 10/4/8.1 lan3 CLAIMED INTERFACE
lan 2 10/4/16 btlan1 CLAIMED INTERFACE HP HP-PB 100 Base TX card
lan 1 10/12/6 lan2 CLAIMED INTERFACE Built-in LAN

#netstat -i

Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
ni0* 0 none none 0 0 0 0 0
ni1* 0 none none 0 0 0 0 0
lo0 4608 loopback localhost 3462032 0 3462030 0 0
lan0 1500 192.168.200 server12 120468 0 109840 4 100
lan2 1500 223.4.202 server12 3522950 0 1754285 0 0
lan1 1500 223.4.200 server12 4653672 0 8085457 1 46307

Re: network collisions

Dirk Wiedemann — Thu, 12 Sep 2002 05:16:00 GMT

Hello Bkumar,

please check your settings for speed and duplex mode (using lanadmin) on lan1 and the switch / hub it is attached to.
This settings must be the same.
Have also a look at the excellent explanations from U.SivaKumar on this thread: http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x8321543254bfd611abdb0090277a778c,00.html

regards
Dirk

Re: network collisions

Bill Thorsteinson — Thu, 12 Sep 2002 13:42:48 GMT

If you are running backups over a half-duplex connection
you should expect a lot of
collisions. Switch to
full-duplex if at all possible.

Re: network collisions

BKUMAR — Thu, 12 Sep 2002 16:30:11 GMT

Thx for the replies....
i am able to get the speed 10 MBPS but how get the duplex from the below ...pls guide me

thx in advance
LAN INTERFACE STATUS DISPLAY
Thu, Sep 12,2002 13:30:23

Network Management ID = 6
Description = lan1 Hewlett-Packard LAN Interface Hw Rev 0
Type (value) = ethernet-csmacd(6)
MTU Size = 1500
Speed = 10000000
Station Address = 0x80009d416e1
Administration Status (value) = up(1)
Operation Status (value) = up(1)
Last Change = 3901
Inbound Octets = 359769583
Inbound Unicast Packets = 3603244
Inbound Non-Unicast Packets = 1368966
Inbound Discards = 0
Inbound Errors = 0
Inbound Unknown Protocols = 824155
Outbound Octets = 2289979609
Outbound Unicast Packets = 8047733
Outbound Non-Unicast Packets = 47351
Outbound Discards = 246
Outbound Errors = 0
Outbound Queue Length = 0
Specific = 655367

Press to continue

Ethernet-like Statistics Group

Index = 6
Alignment Errors = 0
FCS Errors = 0
Single Collision Frames = 34076
Multiple Collision Frames = 12215
Deferred Transmissions = 3397171
Late Collisions = 0
Excessive Collisions = 1
Internal MAC Transmit Errors = 0
Carrier Sense Errors = 0
Frames Too Long = 0
Internal MAC Receive Errors = 0

Re: network collisions

Dirk Wiedemann — Thu, 12 Sep 2002 18:10:22 GMT

Hello Bkumar,

I don't know what exact type of lancard is build-in in a K server. But I wonder why the duplex status is not displayed in "Description" line from lanadmin output.
You can try to set it with the lanadmin command:
"lanadmin -X 10FD 6" sets the nic to 10 MBPS full duplex. If FD isn't supported an error occurs.
Another way is to change the lancard settings with sam.
And if you can't set the nic to the full duplex mode you only can try to set your switch/hub connected to configure to half duplex.

regards
Dirk

Re: network collisions

Ron Kinner — Fri, 13 Sep 2002 16:51:40 GMT

Believe the description line doesn't talk about duplex if the card can't do anything but half duplex.

Most of the early LANs were 10 half and that's what the built-in card is. Nothing you can do other than install a new 10/100 card and that won't help you if you are not attached to a device which supports 100 full.

However, the number of collisions is not that excessive (0.57%) so I do not think that is your problem.

What does look strange is the number of deferred transmissions. This is way too high. This is an indication that the LAN is overloaded or that another device is babbling so that the PC can not send out a packet when it wants to but has to wait for a (rare) gap in the traffic to send. Could possibly be a problem with the other end being 100 Full and not letting it get a word in edgewise but the number of incoming packets seems a bit too low for that. What else is on the same LAN? And what kind of hub or switch are we talking about.

Can you disconnect both the K and the backupdevice from the hub/switch and just connect them with a crossover cable for a test?

A sniffer or tcpdump could probably tell you who the culprit is quite easily.

Ron