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Traffic between blades when using VLAN tunneling

danos
Occasional Contributor

Traffic between blades when using VLAN tunneling

Hello,

 

I want to configure virtual connect to use tunneling mode but we are wondering if the traffic with this mode always go through the external switch although the communication is between the same VLAN in different blade.

 

I have the same doubt than Mike O.

 

http://h30499.www3.hp.com/t5/HP-BladeSystem-Virtual-Connect/Question-about-traffic-between-blades-in-same-chassis-when-using/m-p/6551176

 

Thanks, best regards.

 

 

4 REPLIES
danos
Occasional Contributor

Re: Traffic between blades when using VLAN tunneling

Hello,

I've found this document and it seems the traffic has to reach the external switch, thus has to go out and go in again. However, this example is between tunnel and mapped mode, and I want to configure interfaces of both blades in the same tunnel.

Page: 7 and 8:

 

http://h20566.www2.hp.com/portal/site/hpsc/template.BINARYPORTLET/public/kb/docDisplay/resource.process/?javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken&javax.portlet.rid_ba847bafb2a2d782fcbb0710b053ce01=docDisplayResURL&javax.portlet.rst_ba847bafb2a2d782fcbb0710b053ce01=wsrp-resourceState%3DdocId%253Demr_na-c01608922-11%257CdocLocale%253D&javax....

Any idea about traffic between two blades in the same tunnel? The switching is inside the chassis or outside?

Thanks, best regards.

 

Mike O.
Regular Advisor

Re: Traffic between blades when using VLAN tunneling

I had come across that document, too.

 

I've never received any definite answer, but from everything I've found, I think there is no way it can route the traffic without going outside.  

 

All the documentation says that tunnel mode "passes the traffic through without examining it".  Without opening up the packet, there wouldn't be any way for Virtual Connect to determine which VLAN(s) the traffic goes to or to know where to send it to.

danos
Occasional Contributor

Re: Traffic between blades when using VLAN tunneling

Hi Mike,

 

I've configured virtual connect in tunnel mode, I've done ping between two virtual machines from different blades and after this I've shutdown the interface in the switch and icmp traffic kept working. Therefore, traffic doesn't go outside.

 

Great.

 

Thanks, best regards.

Mike O.
Regular Advisor

Re: Traffic between blades when using VLAN tunneling

Thanks for the comment. 

 

That's interesting, although it's also a little suprising.  Everything I've seen says that in tunnel mode, virtual connect just passes it through and doesn't examing the packet.  If one VM is on VLAN1 and the other is on VLAN2, I woudn't think Virtual Connect would know to keep it local.  Maybe VC does examine it enough to see what VLAN's are on the port and keep them local.