Link between VDCs Should be physical .

[Dhari Kh Abedula]

As fair as I know the connection between VDCs in N7K For example should be physical . And there is No leaking way internal .

the question is How the Admin VDC able to jumping between the VDCs? what is the 

mechanism the NX-OS using for that ? 

[Hanfeng Cai]

You can't allow front panel port to admin VDC, that's impossible.

[Andrea Testino · Accepted solution]

Hi there,

"The Admin VDC is a specialized VDC for administrative functions but also has a restriction that warrants mentioning. It is not possible to have an Ethernet interface allocated to the Admin VDC and it is not possible to have any L2 or L3 protocols in the Admin VDC. Admin VDC can be accessed only via the Console or Management ports on the Supervisor modules. No “inband” access via an interface, including loopbacks, can be configured. "

A great Chalk Talk regarding Nexus 7000 VDCs was provided here a few years ago -- Highly encourage going over it:

https://community.cisco.com/t5/data-center-documents/chalk-talk-admin-vdc-on-nexus-7000-explained/ta-p/3134781

Hope that helps.

[Dhari Kh Abedula]

Thank you that helps a lot. 

[Dhari Kh Abedula]

It is possible to Do Upgrade IOS for Specific VDC only since the VDC Consider isolated Devices ?
Or I have to upgrade all the Box to upgrade all VDCs ?

[Andrea Testino]

NX-OS upgrades are chassis-wide only.

Thanks!

[Dhari Kh Abedula]

So if I have an issue with one VDC which is I have now. (ARP with Tunnel interface issue related to IOS Bugs ) I have to stop all my business ( 5 VDCs ) just to fix this issue!!!

this is really big issue I think!

[Andrea Testino]

Nexus 7000/7700s support ISSU (In-Service Software Upgrades; assuming you have SUP redundancy). The chassis can be upgraded live with little to no disruption. 

Understanding In-Service Software Upgrades

Cisco Nexus 7000 Series NX-OS Software Upgrade Guide

Thanks!