The 7210 SAS router generates this route type to advertise for multi-homing functions. The system can generate two types of Ethernet Auto-Discovery (AD) routes:
Ethernet AD route per-ESI
Ethernet AD route per-EVI
The Ethernet AD per-ESI route uses the following fields and values:
Route Distinguisher
This is taken from the service-level RD.
Ethernet Segment Identifier (ESI)
This contains a 10-byte identifier as configured in the system for a specified ethernet-segment.
Ethernet tag ID
This value, MAX-ET (0xFFFFFFFF), is reserved and used only for AD routes per ESI.
MPLS label
This is zero (0).
ESI label extended community
This includes the single-active bit (0 for all-active and 1 for single-active) and ESI label for all-active multi-homing split-horizon. The 7210 SAS always sets the single-active bit to ‟1”, as long as single-active is supported. In addition, 7210 SAS does not allocate and send the ESI label for single-active multi-homing.
Route-target extended community
This is taken from the service level route target (RT).
The system can send only a separate Ethernet AD per-ESI route per service.
The Ethernet AD per-EVI route uses the following fields and values:
Route Distinguisher
This is taken from the service level RD.
Ethernet Segment Identifier (ESI)
This contains a 10-byte identifier, as configured in the system for a specified ethernet-segment.
Ethernet tag ID
This is zero (0).
MPLS label
This encodes the unicast label allocated for the service (high-order 20 bits).
Route-target extended community
This is taken from the service level RT.