Using 1Gb Uplinks on VC Flex-10

[chuckk281]

We were asked: Customer wants to uplink Flex-10 module at 1gb until they move into a new data center in a few months. Can they uplink the Flex10 module at 1gb? They can use 1Gb SFP on the Flex-10. 453151-B21 HP BLc VC 1Gb SX SFP Opt Kit Or 453154-B21 HP BLc VC 1Gb RJ-45 SFP Opt Kit Here is the part numbers link: http://h18004.www1.hp.com/products/quickspecs/13127_div/13127_div.pdf And the info is in the support manual: http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01608922/c01608922.pdf?jumpid=reg_R1002_USEN

[chopper3]

Chuck I believe that they could use 10Gb SFP+'s today as they'll switch down to 1Gb if they can't negotiate 10Gb - that way there's less to change when they move.

[chuckk281]

Thanks Chopper3. I will suggest that to them.

[chuckk281]

I got this from one of the engineers here. "No. If you use a 10Gb SFP+ module, you can only connect it to a 10Gb port following the same standard (SR, LR or LRM) on the other side, and the link will operate at 10Gb. The auto-negotiation that may occur with Flex-10 is if you connect a Flex-10 NIC in a server to a non Flex-10 switch or VC module that has 1Gb downlinks: the Flex-10 NIC will then automatically go down to 1Gb but this only applies to the link between the server and the interconnect (i.e. the backplane)."

[Leng Wee]

Hi Chuck, so is it possible to use 453154-B21 HP BLc VC 1Gb RJ-45 SFP Opt Kit on the uplink port of VC Flex-10? Reason being we will plan for 10G FC uplink in next year budget as cisco 10G prices are still way high this year I was thinking of just populating all 16 ports of the Flex-10 modules with the SFP 1Gb RG-45 first (since we will start with just 4-5 blades per chassis running esx. Next year we will then expand to the max 16.

[Jeroen_Kleen]

Hello Leng Wee, Yes this will be possible. Keep however the following in mind when using the uplink ports on the VC flex10 module: X1 is shared between a SFP+ and the CX4 port. You can only have 1 connected as both have the ID of X1. So if you use CX4 for stacking link then you can't use the X1 SFP+ port X2-X6 are normal dedicated SFP+ uplink ports that can use all 10GB SFP+ or 1GB SFP+ modules and that don't share the port with any other port. You can always use these uplink ports as uplinks to a higher core switch. X7 & X8 are again shared ports. They are shared with the the 2 10GB interlinks that are available between the VC module in bay 1 and in bay 2. You should ALWAYS have at least 1 of these interlinks available;meaning you shouldn't use both X7 & X8 at any time. As soon as you put a SFP module in the X8 port and get a active link on this SFP+ uplink port then then the X8 interlink connection will become disabled. So to summarize; if you don't use any other VC module in any other horizontal bays except for bay 1 & 2 then you have max. 7 uplink ports available. If you have more VC modules in bays 3-8 then you loose 1 uplink port for the stacking cable. sidenote: If you have cheap CX4 ports available on your CISCO switch then you can use as well a SFP+ copper cable 0.5m for stacking (on a X2-X7 port) to still start easily and in a 'cheap' way with at least 1 10GB uplink port per VC module. Enjoy? Cheers, Jeroen

[konakcc]

I have to agree with Jeroen, there are simplier ways to do this. The cost to deploy 8 1 GE ports exceeds the cost of a 10GE port so why not just enable one 10GE port on each switch.

[Pascal]

we had the same questions, after some studies, cost per port was better using 10 Gb instead of multiple one Gb even on core switches side.

[Adrian Clint]

Hi Jeroen I've always assumed I could add 1Gb SFPs to the 10Gb SPF+ ports as you say. But I did a Matrix config in SalesBuilder today and it would only let me add 1Gb SFPs to the SFP ports. I could not add them to the 10Gb SPF+ ports.