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10 Gb SFP+ copper cable ...and their usage

Occasional Advisor

10 Gb SFP+ copper cable ...and their usage

Just some words about a lil adventure i wanted to share with Flex-10 and 10 Gb network cables. We are building a full vmware plat-form (50 host at the moment) and did choose to connect our C7000 with Flex-10 technologies. Core switches are nexus 5020 from Cisco and we have 2 of them. Each C7000 has 2 flex-10, each of them connected to one nexus thorugh a 10 Gb link. On nexus side, configuration is very simple and no port channel are defined because for the moment we prefer the active/passive(failover) mode on flex-10 side for the uplink. Luckily our core switches are very close to the C7000 so we ordered to Cisco copper g10 Gb SFP+ cable (3 - 5 meters long) wich are the less expensive solutions to link c7000 et nexus siwtches. Once connected, the port are negotiated normaly, though on HP side you get a nice message "Vendor unsupported ... and then it is impossible to use the port in an uplink. We then bought new cables from HP this time, exactely the same, branded HP instead of Cisco, connected them and saw again the ports up on both side. And then a message from cisco device : Vendor not supported ...But we had some luck there, Cisco do not block the port like HP does so all is working fine even with that warning, no error at all on both side and we were able to push the network up to 7-8 Gb/s between 2 vm on 2 different C7000 (memory transfer test) without any trouble. Note that the nexus 5000 cisco solution is also pushed and sold by HP. The only last thing we have to look out, is despite the failover mode we have on flex-10 ulpink config, we get some inbound traffic only on the passive flex-10. Beside that we are pretty happy with the solution.

10 Gb SFP+ copper cable ...and their usage

Interesting article Pascal. I was aware of the cabling issue (HP prefers to sell its own cables, pretty arrogant to block the cisco SFPs i feel). However, the last thing you say interests me: when you speak of inbound traffic on the standby link, what exactly do you mean ? inbound traffic on the nexus (this would be strange) or inbound traffic on the flex module (this would be normal)
Occasional Advisor

10 Gb SFP+ copper cable ...and their usage

I was refering to the traffic coming from the nexus to the passive flex. By the way, why the inbound trafic would be normal ? [Updated on 9/2/2009 9:49 AM]
Neighborhood Moderator

Re: 10 Gb SFP+ copper cable ...and their usage

Do know that with Virtual Connect 3.01 Firmware, VC now supports Cisco and Brocade (3rd party) DAC cables and SFP+ transceivers.  3.01 also adds some additional funcitonality that will allow other DAC cables, as long as they follow this criteria:


•Connector = copper pigtail

•Transceiver code = active cable or passive cable

 •Speed > 10gb

•Length  =1m - 7m, inclusive


If it does, then VC will log that cable as "Unsupported" in the SYSLOG.

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