[K12OSN] Network Question

Jim Christiansen christiansen_j at hotmail.com
Sat Feb 12 23:23:07 UTC 2005

Hi Terrell,

All of the switches go into new 10/100 dell or dlink switches.  I don't know 
more than that, but I'll check.  Our cables are rarely checked after 
install... I know, but our techie is the only one for 9 schools and ...

We did install a new fiber backbone at your and a couple of others 
encouragement last summer.  Things were just awesome here for almost 3 
months, until more old recycled cat5 got added to the extremities of the 
network.  Until then, the K12LTSP server system ran without a single issue- 
smb printing, nis, nfs, clients- all perfect. Now sometimes we can't print, 
kids can't access the NIS server (also the K12LTSP server) or clients just 
drop off.

How do I check to see if autonegotiation is is on?

Thanks,  Jim

From: "Terrell Prudé, Jr." <microman at cmosnetworks.com>
To: jim at linux.ca,"Support list for opensource software in 
schools." <k12osn at redhat.com>
Subject: Re: [K12OSN] Network Question
Date: Fri, 11 Feb 2005 22:43:46 -0500

Jim Christiansen wrote:

>Hello,  Our technician was in the building pulling cat5 and after he
>left this am, my librarian came to me to inform me that the clients
>were running at 1/2 speed.
>I just thought to run ifconfig and I see carrier:14197 and
>overruns:12141....   Great.  I know this isn't good.
>Does anyone know what this means?  Thanks,  Jim
>Here is my complete ifconfig:
>[root at linux-thin1 ~]# ifconfig
>eth0      Link encap:Ethernet  HWaddr 00:E0:81:28:27:52
>          inet addr:  Bcast:
>          inet6 addr: fe80::2e0:81ff:fe28:2752/64 Scope:Link
>          RX packets:126270015 errors:0 dropped:0 overruns:12141
>          TX packets:153628098 errors:0 dropped:0 overruns:0
>          collisions:0 txqueuelen:1000
>          RX bytes:1069418867 (1019.8 MiB)  TX bytes:652818974
>(622.5 MiB)
>          Interrupt:169 Base address:0x2000
>lo        Link encap:Local Loopback
>          inet addr:  Mask:
>          inet6 addr: ::1/128 Scope:Host
>          UP LOOPBACK RUNNING  MTU:16436  Metric:1
>          RX packets:315878 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:315878 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:0
>          RX bytes:204548481 (195.0 MiB)  TX bytes:204548481 (195.0

What kind of gear are these drops plugged into?  Hubs, switches, and at what 
speed?  If they're hubs, you're going to see a reduction in throughput.  If 
they're half-duplex switches, it won't be as bad.  Optimum is full duplex.  
If you're using 100Mbps/FDX switches, you might check to see if your 
autonegotiation is 1.) turned on <they usually are by default>, and 
2.) actually working right.

Also, did he perform a full cabling test, and if so, did he give you a copy 
of the results?  Wiring contractors are supposed to do that.


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