diff --git a/files/build_templates/swss_vars.j2 b/files/build_templates/swss_vars.j2
index 1cd95d16a6d..fc975685f59 100644
--- a/files/build_templates/swss_vars.j2
+++ b/files/build_templates/swss_vars.j2
@@ -6,5 +6,6 @@
     "asic_id": "{{ DEVICE_METADATA.localhost.asic_id }}",
     "mac": "{{ DEVICE_METADATA.localhost.mac }}",
     "resource_type": "{{ DEVICE_METADATA.localhost.resource_type }}",
-    "synchronous_mode": {% if DEVICE_METADATA.localhost.synchronous_mode == "disable" %}"disable"{% else %}"enable"{% endif %}
+    "synchronous_mode": {% if DEVICE_METADATA.localhost.synchronous_mode == "disable" %}"disable"{% else %}"enable"{% endif %},
+    "additional_mac": {% if DEVICE_METADATA.localhost.type == "ToRRouter" and DEVICE_METADATA.localhost.subtype == "DualToR" %}"enable"{% else %}"disable"{% endif %}
 }