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Data traffic leaving Virtual Connect Domain Group (VCDG)

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Data traffic leaving Virtual Connect Domain Group (VCDG)

Lee had a question or request for info:





                I know I’ve asked before and don’t think I ever got a definitive response (at least I can’t find it).  Do we have any customer facing documentation that says, “default behavior of Virtual Connect is that traffic within a Virtual Connect Domain Group (VCDG) tagged in the same vNet will not leave the enclosure unless the ‘private network’ option is enabled”?



This is the closest I can get, from the cookbook.  I guess I’m looking for the exact same thing said in the exact opposite way ;)


Private VLANs - Simple Network Connection showing a single Ethernet uplink to a single VC-Enet port

(Port 1). VC-Enet Port 1 is configured as part of the VC Network Prod-Net. As the Private Network feature is enabled on Prod-Net, servers that are connected to Prod-Net will not be able to talk directly to each other within VC, an external router would be required. “Prod-Net” is presented to Server Profiles Web-1 through Web-4. Each profile is applied to bays 1-4 respectively.




Steve had some advice:






It is true, if two (or many) servers are connected to the SAME vNet in the same VC Domain, they will communicate within the VC domain, assuming the Private Networks feature is not enabled.  This could be a simple vNet or a vNet within a SUS.


So, if you take Scenario 1:1 which uses an Active/Stby config, and each server has two NICs on a vNet (left nic and right nic for redundancy), no matter which NIC is active on each server, they will communicate within the VC Domain.  No matter how the VC domain is configured, this will hold true.


Then, if you take Scenario 1:2 which uses an Active/Active config, as an example were we have TWO vNets (left side right side).  If server one is active on NIC  1 and server two is active on NIC 1, both servers WILL communicate on vNet1 and within the VC Domain.  It is important to note that both (all) servers must be active on the same NIC to stay within the vNet and not leave the VC Domain.


However, where traffic may need to leave the VC Domain is that if server 1 were active on NIC 1 and server 2 was active on NIC 2.  If server 1 and 2 need to talk, they would need to leave the enclosure and circle back to the opposite vNet/NIC.  Again, Scenario 2 is an example of this. 


Also, I used Scenarios 1 and 2 as examples, however, this is true for Flex-10 and FlexFabric NICs as well as with Shared Uplink Sets.




Other comments or suggestions for Lee?? Here is a link to the document they are looking at:

NEW! - Virtual Connect Ethernet Cookbook