Hi John/jesse, Thanks for you support and quick response to queries.
There is a slight mis-match in my understanding of NIC interface. After contacting the Hardware folks I was told it's not Fiber port. I want to re-phrase my question as below: "We are using on board network interfaces that are based on Intel 82571 controller and use SFP transceivers. The Intel 82571 controller supports 10/100/1000Mbps operation, however when we are trying to set the interface speed to below 1000Mbps the ports seem to shut down. Note that we are using the RJ-45 1000BASE-T electrical SFPs." Our Hardware is embedded with 4 interfaces based on 82571 controller, out of which,2 ports(Say 1 and 2) are RJ-45 based, and other 2(3rd & 4th) interfaces are based on the HW interface as mentioned above. We are not having any problem in modify the speed of 2 ports based on RJ-45, however facing problem with 3rd and 4th interface. 1. Still the limitation is valid? 2. Please advice us how different driver treats these interfaces comparing to RJ-45 interfaces? 3. What kind of Technical limitation posing this issue? 4. Is there any specific reason for not supporting reduction in speed? 5. Using any specific hardware will suffice the purpose? I mean without modifying the driver? 6. Will there be any problems in application if ITR rate is changed? We appreciate your support on this problem. Regards, --Rajeev On 12/5/08, rajeev naidu <[EMAIL PROTECTED]> wrote: > ---------- Forwarded message ---------- > From: "Brandeburg, Jesse" <[EMAIL PROTECTED]> > Date: Thu, 4 Dec 2008 23:20:43 -0800 > Subject: RE: [E1000-devel] Fiber NICs speed > To: rajeev naidu <[EMAIL PROTECTED]>, "Ronciak, John" > <[EMAIL PROTECTED]> > Cc: "[email protected]" <[email protected]> > > You cannot reduce the link speed of a 1GB fiber NIC. If you're trying > to slow it down you could massively decrease the interrupt rate using > the InterruptThrottleRate module parameter, and try setting it to > 512,512 or something. > > The other preferred way would be to probably use a qdisc in linux like > htb or something to throttle the transmit rate in the stack. > > Jesse > > > -----Original Message----- > From: rajeev naidu [mailto:[EMAIL PROTECTED] > Sent: Thursday, December 04, 2008 10:58 PM > To: Ronciak, John > Cc: [email protected]; Linux NICS > Subject: Re: [E1000-devel] Fiber NICs speed > > Hi John, > > Thanks for the input. I am referring Fiber Ethernet(1G) port. > > Is there any way or workaround possible to reduce the speed > programatically by tweaking > some setting? > > Regards, > --Rajeev > > On 12/1/08, Ronciak, John <[EMAIL PROTECTED]> wrote: >> First do you mean 82571? Also, are you really talking Fiber Channel or >> are >> you talking about using a fiber Ethernet port? The 82571 won't work in a >> Fiber Channel environment. Connected to a fiber Ethernet port it will >> only >> operate on a 1 gigabit full duplex link, by specification. So if you are >> trying to change speeds on a fiber Ethernet port, the error messages are >> correct. >> >> Cheers, >> John >> ----------------------------------------------------------- >> "Those who would give up essential Liberty, to purchase a little temporary >> Safety, deserve neither Liberty nor Safety.", Benjamin Franklin 1755 >> >> >>>-----Original Message----- >>>From: rajeev naidu [mailto:[EMAIL PROTECTED] >>>Sent: Monday, December 01, 2008 12:10 AM >>>To: Linux NICS >>>Cc: [email protected] >>>Subject: [E1000-devel] Fiber NICs speed >>> >>>Hi, >>> >>>I am working on a H/W which uses e1000 82751 NIC. The Network >>>interface connected(uses) via Fiber channel. I am facing a problem >>>when i try to change(reduce the speed) the Interface space 100 or 10. >>>The ioctl command fails with -1 ("Unsupported Speed/Duplex >>>configuration") and when looked into the code i found a statement: >>> >>>/* Fiber NICs only allow 1000 gbps Full duplex */ . >>> >>>Can somebody tell me is there any H/W limitation? >>> >>>Regards, >>>--Rajesh >>> >>>--------------------------------------------------------------- >>>---------- >>>This SF.Net email is sponsored by the Moblin Your Move >>>Developer's challenge >>>Build the coolest Linux based applications with Moblin SDK & >>>win great prizes >>>Grand prize is a trip for two to an Open Source event anywhere >>>in the world >>>http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>>_______________________________________________ >>>E1000-devel mailing list >>>[email protected] >>>https://lists.sourceforge.net/lists/listinfo/e1000-devel >>> > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > E1000-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/e1000-devel > ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel
