JCNR as a Transit Gateway

SUMMARY JCNR can act as a transit gateway for external traffic. As a transit gateway, JCNR is neither the source nor the destination for the traffic, but an intermediate hop. It acts as a vanilla router to switch traffic between multiple physical interfaces.

Starting with Juniper Cloud-Native Router (JCNR) Release 23.2, JCNR can now act as a transit gateway for external traffic. As a transit gateway, JCNR is neither the source nor the destination for the traffic, but an intermediate hop. It acts as a vanilla router to switch traffic between multiple physical interfaces. Depending on the forwarding state, JCNR can encapsulate or decapsulate the traffic between interfaces.

Note:

Starting with JCNR Release 23.2, JCNR supports multiple fabric interfaces that enable it to function as a transit gateway.

JCNR has to be deployed in the L3 mode to perform the transit router functionality. Add all physical interfaces (physical and virtual functions) as fabric interfaces in the helm chart before deploying the JCNR. The deployed JCNR does not support editing or changing the fabric interfaces during run time. However, you can create or remove pod interfaces during run time. Here are example helm chart configurations:

You need to configure an IP address on the loopback interface and use it as a tunnel endpoint for each JCNR instance. The loopback IP address is the next hop address which BGP advertises to its peers. All data packets with encapsulations like MPLSoUDP will have the outer IP address as this loopback IP address. The loopback IP address is reachable via any of the physical interfaces. The loopback IP address should be in a /32 subnet without a MAC address. For example: