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Virtual Connect Flex-10 and Cisco proprietary PVLANS

Trusted Contributor

Virtual Connect Flex-10 and Cisco proprietary PVLANS

Brian had a Cisco question:




I have a customer that seemed to be working for quite a while using Cisco PVLANs on the uplink Nexus and the Vsphere side.  All traffic was routing through tunneled uplinks.  It seems now hosts that are on the community PVLAN can’t connect to the gateway on the promiscuous PVLAN.


Do we know if anything major has changed recently in VC that would have made this not work properly?  As I understand it in tunnel mode we would just ignore the PVLAN and standard VLAN tags coming in and out of the hosts and uplinks and VC would be doubletagging  the packets coming on and off the FlexNIC to the tunneled Vnet but we still would be leaving the rest alone (original and PVLAN id’s alone)


Any comments or thoughts around this would be greatly helpful.




Reply from Chris:




We have never claimed support for PVLAN, nor provide support for PVLAN with Virtual Connect.  PVLAN is a proprietary mechanism, and not a standards protocol.  Yes, there is an RFC (specifically RFC5517), but an RFC does not make a standard protocol.  It has to be done through the IEEE 802 group.  There have been proposals to extend 802.1Q to provide PVLAN in a standards way, but nothing has come of it.


Plus, with a Tunneled Network, there is no guarantee that hosts wouldn’t be able to communicate to other hosts within VC, as VC doesn’t inspect the Customer VLAN ID’s, let alone understand what is a Community versus Isolated VLAN.  So this issue really is moot.




Have you worked with PVLANs and Virtual Connect?