Nexus c7706 VDC or not?

[benediktsv]

Hi all

So I'm more of a SP guy, but have the task of replacing our old trusty 6500's (sup720) and our IT dep. bought few 7706'es but as we run them as PE's into our SP network the task to configure them falls to me ;)

So I'm faced with configuring them with VDC or not 

I have heard some features are not fully supported in the VDC domains. We don't have any imminent/direct requirements for multiple VDC contexts at the moment, but we don't what the future holds.

So should we configure the switch in VDC mode, or just as a single.

Features we will be running MPLS/BGP/OSPF backbone - and basic PE-CE stuff.

- Benni

[Hector Gustavo Serrano Gutierrez]

Hi @benediktsv,

When you install your new Nexus 7700s, during the initial configuration script there will be a question about enabling the Admin VDC or not.

If you hit 'Yes', you will find that the purpose of the Admin VDC is just to create/modify/delete and connect to all other VDCs that can be created in the Nexus 7700. This Admin VDC cannot be configured to pass regular network traffic nor with any routing protocol, etc. Its purpose is purely to administer all the other VDCs in the Switch.

From the Admin VDC you can create your first "regular" VDC for your production environment. You can create more VDCs depending on your needs in the future.

If you don't enable the Admin VDC, you will start with the Default VDC, where you can configure all you need to pass regular network traffic, routing protocols, etc. You can still use more VDCs in the future of course and create/modify/delete and connect to them from this Default VDC, just like from the Admin VDC.

The difference is subtle between these two options but the benefit of enabling the Admin VDC in the initial configuration script is that you are now in the mentality that you are managing VDCs in your Nexus 7700. You start by creating your first VDC and grow up to 8.

This example shows the prompts at a clean bootup to enable the admin VDC:

Enter the password for "admin":
Confirm the password for "admin":
Do you want to enable admin vdc (yes/no) [n]:yes

Documentation:

Cisco Nexus 7000 Series Virtual Device Context Configuration Guide
Chapter: Configuring an Admin VDC

I hope this helps.

Best Regards.

[benediktsv]

Hi - thanks four your reply

I have already played with the VDC config and it's quite clear to me.

The question is more on the actual features and support of routing/LDP/MPLS/MP-BGP etc inside of the VDC - if there is any downside of using multiple VDC's or not ?

- Benedikt

[Hector Gustavo Serrano Gutierrez]

Hi @benediktsv,

All the protocols required for your Nexus 7700 to act as P or PE (OSPF or ISIS, LDP, BGP VPNv4, BGP IPv4 MDT, VRFs, an IGP for PE-CE) are completely supported on a VDC with the exception of the Admin VDC of course.

Just run install feature-set mpls on the Admin VDC, go in your VDC and activate it.

If there is no Admin VDC as you decided not to have it, just run install feature-set mpls and activate it in the Default VDC.

If you later on create another VDC, go in that other VDC and also activate it there.

The following example shows how to install and enable the MPLS feature set in the default VDC on the device:

switch# configure terminal
switch(config)# install feature-set mpls
switch(config)# feature-set mpls
switch(config)# exit
switch#

The following example shows how to install the MPLS feature set on the device and then switch to a VDC and enable the feature set in that VDC:

switch# configure terminal
switch(config)# install feature-set mpls
switch(config)# exit
switch# switchto vdc vdc1
switch-vdc1# configure terminal
switch-vdc1(config)# feature-set mpls
switch-vdc1(config)# switchback
switch#

from:

Cisco Nexus 7000 Series NX-OS MPLS Configuration Guide
Chapter: Configuring the MPLS Feature Set

Don't panic if after that you don't see the required commands available in the CLI, you also need to explicitly activate all of the features in the VDC you are working on.

configure terminal
!
feature ospf
feature bgp
feature pim
feature mpls ldp
feature mpls l3vpn
feature mvpn

Best companion resource for this venture:

Cisco Nexus 7000 Series NX-OS MPLS Configuration Guide