Wireshark-users: Re: [Wireshark-users] 8-10% packet error/loss is normal wirednetwork?

Date: Thu, 12 Jul 2012 18:06:25 -0400
Well, the actual packet loss was under 2%, but still too high for local
traffic on a wired LAN.

Original Message:
-----------------
From: Shawn T Carroll shawnthomascarroll@xxxxxxxxx
Date: Thu, 12 Jul 2012 14:20:13 -0700 (PDT)
To: ktan@xxxxxxxxxxxxxxxxxxx, wireshark-users@xxxxxxxxxxxxx,
wireshark-users@xxxxxxxxxxxxx
Subject: Re: [Wireshark-users] 8-10% packet error/loss is normal
wirednetwork?


+1.  And, for what it's worth, just hearing that the value of packet loss
was 8-10% made it sound to me like a duplex mismatch was at fault, though
this varies with the data rate and the direction that of the traffic (it's
the full to half direction that causes collisions and loss)

Shawn


________________________________
 From: Kok-Yong Tan <ktan@xxxxxxxxxxxxxxxxxxx>
To: wireshark-users@xxxxxxxxxxxxx 
Sent: Thursday, July 12, 2012 5:15 PM
Subject: Re: [Wireshark-users] 8-10% packet error/loss is normal wired
network?
 
On 7/11/12 15:56, Flako wrote:
> 
> Hello Prigge, Jim
> The printer is at 100Mb / s FULL with autonegotiation disabled, the
> desktop was as 1Gb / s FULL with autonegotiation enabled.
> The swicth A (100Mb / s) and B (1Gb / s) are connected directly to each
other.
> 
> 
> Now connect the Desktop Printer and a switch C (only two), then swich
> C connects directly to swicth A.
> I'm sniffer on the Desktop to see differences and discard things. I
> tell them when finished.
> 
> Thank you for writing so far.
> (Examples of how to find a fault will serve me now or the next)
> 

Are your statements above accurate (printer has autonegotiation *DISABLED*
and desktop has autonegotiation *ENABLED*)?  Both devices *MUST* match,
even if one has autonegotiation enabled.  i.e., If the desktop has
autonegotiation enabled, then the printer *MUST ALSO* have autonegotiation
enabled.  Otherwise autonegotiation will fail and the device with
autonegotiation enabled will drop down to half duplex.   See this:

<http://en.wikipedia.org/wiki/Duplex_mismatch#Duplex_mismatch_due_to_autoneg
otiation>

Hansang Bae mentioned this in a session at a prior Sharkfest during one of
his very illuminating "Deep Dive" packet analysis sessions.

Reality Artisans, Inc.             #   Network Wrangling and Delousing
P.O. Box 565, Gracie Station       #   Apple Certified Consultant
New York, NY 10028-0019            #   Apple Consultants Network member
<http://www.realityartisans.com>    #   Apple Developer Connection member
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at<https://keyserver.pgp.com>




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