Wireshark · Wireshark-users: Re: [Wireshark-users] Slow gigabit network

[Scott Chapman <scottchapman@xxxxxxxxxxxxxx>]

I have experimented with forcing 1000/full explicitly on both sides with out any effect.

Incidentally, I do occasionally get 20MB/sec.

Before I go buy anew switch I was hoping to learn how to use wireshark to see what is going on, perhaps to help point the finger somewhere...

-Scott

----- Original Message -----
From: "EDWARD HILL" <EHill@xxxxxxxxx>
To: "Scott Chapman" <WireShark@xxxxxxxxxxxxxxxxx>, "Community support list for Wireshark" <wireshark-users@xxxxxxxxxxxxx>
Sent: Tuesday, March 10, 2009 10:00:09 AM GMT -05:00 US/Canada Eastern
Subject: RE: [Wireshark-users] Slow gigabit network

Since the switch is not a managed switch, set your server nic to auto. If that does not work drop the nic to 100/full and see what you get. If the throughput is higher at the 100/full it will be either a driver on the server side or the switch. I recommend getting a managed switch. when your running gig you want to be able to see both sides.

 

Ed

---

From: wireshark-users-bounces@xxxxxxxxxxxxx [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of Scott Chapman
Sent: Saturday, March 07, 2009 1:12 PM
To: netztier@xxxxxxxxxx
Cc: Community support list for Wireshark
Subject: Re: [Wireshark-users] Slow gigabit network

Actually I know the cables are OK because I have used the intel drivers to validate the cables. All indications (lights on cards, and switch), along with diagnostics in the drivers, all indicate gigabit full duplex

I am not using a managed switch, so I can't get any info from it.

I have also used iPerf which shows me similar results.

-Scott


----- Original Message -----
From: "Marc Luethi" <netztier@xxxxxxxxxx>
To: "Community support list for Wireshark" <wireshark-users@xxxxxxxxxxxxx>
Cc: "Scott Chapman" <WireShark@xxxxxxxxxxxxxxxxx>
Sent: Saturday, March 7, 2009 4:14:13 AM GMT -05:00 US/Canada Eastern
Subject: Re: [Wireshark-users] Slow gigabit network

On Fri, 2009-03-06 at 21:29 -0500, Scott Chapman wrote:

> So, the problem I have is that I get about 12-14MB/sec when I copy
> files.

Might be protocol overhead, as (almost) usual. Yet, assuming that the
cabling is okay from the fact alone that both cards connect at 1Gbps is
wrong. There might still be CRC errors (and hence packet loss and TCP
retransmissions), or flow control might be stepping in:

http://www.smallnetbuilder.com/content/view/30212/54/

If the switch is a managed one, have a good look at each port counter,
or see if you can undig some of those counters from the depths of your
NIC's driver. Wireshark might even be able to show flow control pause
frames being sent or received by the system it runs on.

Get a Windows or Java version of iPerf or jPerf, and use it to shove
data from box to box. Here's how - same procedure for Linux and Windows.

http://ubuntuforums.org/showpost.php?p=6758444&postcount=7
http://ubuntuforums.org/showpost.php?p=6522634&postcount=4

If you get reasonable throughput numbers here, you can safely assume
that the IP stacks and storage I/O systems are in good shape.

Then you can start to deep into the analysis of the involved protocols
like CIFS, NetBIOS-over-IP or NFS.

regards

Marc