RE: Basic flow control concept

From: nakashita (isao_nakashita@nifty.com)
Date: Sat Dec 01 2007 - 23:49:15 ART

 Dear David Prall,

Thanks for replying quickly,I cound't sleep at all.
Because I will have to inspect this issue tomorrow

> Traffic generatorA----Cat65A----cat65B-----Traffic generatorB
> 100Mbps (Fix) 1G (fiber) 1G (fiber)

>I believe by default they are only configured to receive pause frames, and
not send.

Yes,It was exactry true,so I configerd cat65A's interface gi "send on",
and I conformed "sh int gig x/x flowcontrol" and "sh interface".

Cat65A setting was "send on" according to ope from your command output
and cat65B setting was "receive on" it was default setting.
When I traffic transmitted from TgB to TgA,I captured Cat65A TX　Packet,
but I couldn’t catch "Pause frame" at all.

Yours sincerely,
Isao Nakashita

-----Original Message-----
From: David Prall [mailto:dcp@dcptech.com]
Sent: Sunday, December 02, 2007 11:28 AM
To: 'nakashita'; ccielab@groupstudy.com
Subject: RE: Basic flow control concept

I believe by default they are only configured to receive pause frames, and
not send.
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/c
onfiguration/guide/sw_int.html#wp1041210

"sh int gig x/x flowcontrol" will display current settings.

David 

--
http://dcp.dcptech.com

> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of nakashita
> Sent: Saturday, December 01, 2007 9:07 PM
> To: ccielab@groupstudy.com
> Subject: Basic flow control concept
>
> Hello everyone,
>
> I recently have a little bit nerves for my job.
> You might know about flow control between L3 switch (cat65) and L3
> switch (Cat65).
>
> The following is the diagram. Sorry,
> I forgot IOS, so please tell me a basic concept.
>
>
> Traffic generatorA----Cat65A----cat65B-----Traffic generatorB
>                100Mbps (Fix) 1G (fiber)  1G (fiber)
>
>                            .1   .2         .1 .2            .1   .2
>                192.168.0/24     192.168.1/24     192.168.2/24
>
> If Traffic transmits from Traffic generator B to Traffic generatorA,
> burst congestion will happen to Cat 65's output interface.
> Because TGA and Cat65A line is 100Mbps.
> As a result Cat65A will send Pause Frame to notify about congestion to
> Cat65B.
> However, Cat65s didn't send and receive Pause frame at all.
> The purpose is to confirm flow control specification.
> Could you tell me some tips to solve problem how I can see Pause
> Frame.
>
> Yours sincerely,
> Isao Nakashita
>
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