Fix port speed to 1 Gbit/sec

Hi Hersh,

Thank you for your answer.

I think so. The EMC DS300-B Specification sheet (http://www.emc.com/collateral/hardware/specification-sheet/h5528-connectrix-ds300b-ss.pdf) shows:

• Auto-sensing of 2, 4 and 8 Gb/s port speed
• Speed matching between 2, 4 and 8 Gb/s ports

But the Brocade 300 Specifications (http://www.brocade.com/products-solutions/products/switches/product-details/300-switch/specifications.page)shows:

• auto-sensing of 1, 2, 4, and 8 Gbps port speeds
• speed matching between 1, 2, 4, and 8 Gbps ports

DS300-B is the OEM Brocade 300.

I wonder if that is a typo on Brocade's part and EMC got it right? If you look at the SFP specs from HBA vendors (which ususally are the OEM providor for array SFPs) all the 8Gb FC SFPs only operate at 8/4/2 Gb and do not support 1Gb.

Yes. I second that. As per the EMC documents, this switch auto negotiates only to 2/4/8 Gb.

Thanks,

Ali

I tried with a 4 Gbps non-Brocade SFP and it wasn'r run.

With a 4 Gbps brocade SFP, it's works perfectly.

Thanks.

If I'm not mistaken you can't use non-Brocade SFPs in Brocade switches anymore. They know the difference. As it was explained to me, Brocade ran into so many problems with quality control on 3rd party SFPs that they have tweaked something (not sure if it is in FOS or hardware) to prevent non-Brocade SFPs from initializing. That being said, there is one special type of SFP that they allow from another vendor, but I think it was for distance extension and was NOT a standard SW MM SFP.

The comments about setting the 8Gb SFP to 1Gb were correct as well. I'm surprised the interface will even allow it, but the actual FC standard does not allow negotiation down more than two levels... so 8Gb will only ever be able to negotiate down to 2Gb or 4Gb. If you HAVE to have 1Gb then you HAVE to have a 4Gb (or 2Gb or 1Gb) SFP. This isn't a vendor thing... it's a Fibre Channel Standards definition thing.

I agree with you Allen. I did verify that with a few switches listed. Its mentioned 8/4/2 for EMC branded switches.

Thanks,

Ali

So I have another thought to add to this thread. In reading the data sheet on the Cisco 8Gbps Switching Modules I noticed that they referred to the ports as 1/2/4/8 autosensing. They also state that the new 8Gbps switching modules support either 8Gbps or 4Gbps SFPs. So Cisco is differentiating between the port and SFP with regards to the supported speeds, and Brocade may have been doing the same in their documentation. The port can operate at 1/2/4/8 Gbps using either 4Gbps or 8Gbps SFPs to achieve this.

Good point Aran!

The switch port itself can be capable of 1/2/4/8G but the SFP you put in it defines if you are limited to the top three or bottom three speeds. If the interface will let you force a port to 1G when it has an 8G SFP then you are effectively disabling the port since that configuration can never actually be achieved. It would be like forcing a port to 8G with a 4G SFP. Not going to work.

I think it comes down to the interface allowing you to select something that may not be possible with the installed hardware. May need some tweaking :-)