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How to SDA Host Onboarding with ISE

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Introduction

Host Onboarding is the term used when connecting an endpoint (hosts , IOT , Other devices) to the fabric , and can be accomplished in a couple of ways.
One option is the "static" approach as oppose to the dynamic and secure approach using  Identity Services Engine (ISE) based on Authentication and Authorization.
With this approach we dynamically assign the endpoint to a VN as well as assigning it a Scalable Group Tag (SGT) providing us with Macro and Micro Segmentation.

In this document we will provide a step by step example how to Onboard an endpoint to the fabric using ISE.

This document assumes you have a fabric already up and running with VNs, IP Pools, SGTs, and AAA settings in place. This document will not focus on these steps.

 

Requirements

  • When writing this doc the following was used.
    DNAC 1.3.1.4
    ISE 2.6 Patch 1
  • Cisco DNA Center with ISE integration
    How To Cisco DNA Center ISE Integration
  • VNs, SGTs, IP Pools, Authentication Template

 

Cisco DNA  Center Deployment Steps

  1. Create the VN . This will be achieved under Policy > Virtual Network
    In this example we have we created a VN named "ENG"
  2. Assign SGTs
    In this example we have added a few SGTs - Engineering, Guests, HR, Students

     

    VN_SGTs_pic2.png

     

  3. Navigate to Provision > Fabric and choose the Fabric you created , Then choose "Host Onboarding"
    You will see the VN that was created in previous steps
    Assign IP pool to VN
    We have reserved an IP pool of 172.16.10.0 and assigned it to "ENG" VN

    IP Pool - VN-subnet.png

    NOTE:When adding the IP Pool to VN it is important to understand the significance of the name created by SDA and why there is an option to actually modify that name. This is out of the scope of this document but you can find the explanation in the following document:
    SDA-Access Authentication Policy Naming Best Practice

  4. The Authentication Template chosen in this example is "Open Authentication" which is in the upper part of "Host Onboarding".

Auth-Temp.png
To check the actual configuration the template applies at the port level we can navigate in Cisco DNA Center to
Fabric Infrastructure , and click on the Fabric Edge device at which time a slide in window will appear with information regarding the specific Edge device. Click on "Configuration" to see the device configuration.
open_auth config.png

The Cisco DNA Center section is complete and in this next section will show the steps needed in ISE to accomplish dynamic Onboarding.

ISE Deployment Steps

The way ISE interprets and views the VN and the IP Pool assigned to it , is by binding it to the SGT that was assigned to the VN, This can be seen in the diagram below under SGT "Engineering".

So lets take a quick look of the steps that were taken ,

  • We created the VN (ENG)
  • We assigned the SGTs to the VN (HR, Engineering, Guests, Students)
  • We assigned an IP pool to VN (172_16_10_0-ENG)
    So if for example we were to take a look at the SGT "Engineering" in ISE , we would see the VN "ENG" and the address pool that we assigned to it in Cisco DNA Center.
    Navigate to Work Centers > TrustSec > Components > Security Groups (which is on the left hand side) and click on SGT "Engineering"
    SGT_ISE_2.png

The next step is to create the "Authorization Profile" which is the Authorization that is applied once the endpoint is Authenticated and meets that Authorization Conditions.

  1. In ISE Navigate to Policy > Policy Elements > Results > Authorization (left hand side) > Authorization Profiles
  2. Click "Add"
  3. Will Name it "Engineers"
  4. Under "Common Tasks" we will check mark "Security Group"
  5. In the first field of "Security Group" we will choose the SGT "Engineering"
  6. Once the SGT is chosen an additional field will appear which is the VN field , We will chose VN "ENG"
  7. As soon as we choose the VN "ENG" the last field will appear , which is the "Subnet/IP Address Pool Name" at this stage we will choose the IP Pool Name "172_16_10_0-ENG" (Note:You may have multiple IP Pools in a single VN)

Your Authorization Profile should look like this.

AuthZ profile 2.png

 

We can now create the Authorization Policy and apply the Authorization Profile we created above (also known as the Rule)
Note: We will not cover the Authentication Policy and we will use default Policy Set

  1. Navigate to Policy > Policy Sets and choose the "Default" just under it by clicking the arrow on the right hand side which will expand the Policy Set
    Policy Set.png

Click on "Authorization Policy" Policy to expand and create a new Authorization Policy Named "Engineering"
Your Authorization Policy should look like this:
Authz Policy.png

Notice the "Security Groups" field is empty , this is because we already applied the SGT in the Authorization Profile so there is no reason to add it here.

 

But what if you did not want to assign an SGT to the endpoint and still have it assigned a VN ?
In this case you would use the "VLAN" option under "Common Tasks" in the Authorization Profile we previously created (Engineers) instead of "Security Group"

Which should look like this:

vlan - vn.png

Make sure to enter the VN name correctly otherwise it will not work , best practice is to copy the VN name from the SGT section and paste it in the field.

You can then use that same Authorization Policy we created previously and if later you wish to start assigning an SGT while Onboarding the endpoint you can choose it from the "Security Groups" field in the Authorization Policy:security group_vlan.png

In this document you have learned how to dynamically assign a VN (Macro Segmentation) and an SGT (Micro Segmentation) while Onboarding an endpoint based on an Authorization Policy.

 

If you have any questions regarding this particular Document or would like to see other walk throughs that extend beyond this topic please let us know on our community page SD-Access Community

 

 

 

Comments
Beginner

How does this SGT/VN  information get translated into VLAN ?