Chapter 12. Multiple Fabrics

12.1.   Multiple Fabrics

12.1.1.  Introduction

The Multiple Fabric feature allows a Node to be commissioned to multiple separately-administered Fabrics. With this feature a current Administrator can (with user consent) allow the Commissioner for another fabric to commission that Node within its Fabric. The new Commissioner MUST have their own Node Operational Certificate (NOC) issued by its Trusted Root Certificate Authority (TRCA). Once commissioning is completed and the Node is properly configured, Administrators on the newly joined Fabric have access to the Node and can perform all administrative tasks.

A Fabric is anchored by its Trusted Root Certificate Authority (TRCA). A TRCA MAY delegate to one or more Intermediate Certificate Authorities (ICA) which issue NOCs. Multiple vendors or compa­ nies can use the same CA hierarchy in which case they will be governed under the same Trusted Root Certificate Authority.

12.1.2.  User Consent

A user who wishes to have an already commissioned Node join another Fabric (and therefore another Security Domain) provides consent by instructing an existing Administrator, which SHALL put the Node into commissioning mode by using steps outlined in Section 5.6.4, “Open Commission­ ing Window”. Administrators SHALL provide a mechanism for the user to thus instruct them.

12.1.3.  Administrator-Assisted Commissioning Method

Administrators SHALL support opening a commissioning window on a Node using the mandatory method described in Section 5.6.3, “Enhanced Commissioning Method (ECM)”. All Nodes SHALL support having a commissioning window opened using the mandatory method described in Section 5.6.3, “Enhanced Commissioning Method (ECM)”.

An Administrator MAY open a commissioning window on a Node using the optional method described in Section 5.6.2, “Basic Commissioning Method (BCM)”, if the Node supports the method.

12.1.4.  Node Behavior

The Node SHALL host an Section 11.18, “Administrator Commissioning Cluster”. The Cluster exposes commands which enable the entry into commissioning mode for a prescribed time, and which SHALL be invoked over a CASE secure channel. See Section 11.18.8.1, “OpenCommissioning­ Window (OCW) Command” and Section 11.18.8.2, “OpenBasicCommissioningWindow (OBCW) Com­ mand”. During such a commissioning window, the Node SHALL maintain its existing configuration, such as its operational network connection and identities, and SHOULD allow normal interactions from other Nodes.