VLAN Bundle Service for EVPN
Starting with Junos OS Release 17.1, VLAN bundle service allows multiple broadcast domains to map to a single bridge domain. Multiple VLANs are mapped to a single EVPN instance (EVI) and share the same bridge table in the MAC-VRF table, thus reducing the number of routes and labels stored in the table. This lowers the control plane overhead on the router. Having a single bridge domain requires all CE devices in the VLAN network to have unique MAC addresses. VLAN ID translation is not permitted as the MPLS encapsulated frames must retain the originating VLAN ID. As such the Ethernet Tag ID in all EVPN routes is set to zero. A VLAN range cannot be specified. The entire VLAN from 1 to 4095 must be bundled on the interface.
Figure 1 illustrates a topology where VID 100 and VID 200 are bundled and assigned to EVI 1. The service provider creates a single broadcast domain for the customer and assigns a preconfigured number of CE-VIDs on the ingress PE routers (PE1 through PE5) to EVI 1. All CE devices use the same CE-VIDs for the EVI.
Using the VLAN bundle service reduces the number of routes and labels, which in turn, reduces the control plane overhead. The trade-off for the ease of provisioning in a customer network is that the service provider has no control over the customer broadcast domain since there is a single inclusive multicast tree and no CE-VID translation. .
Junos OS also supports port-based VLAN bundle service where all of the VLANs on a port are part of the same service and are mapped to the same bundle.
Integrated routing and bridging (IRB) is not supported for VLAN bundle service.