diff --git a/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-C32/td3-a7050cx3-32s-32x100G.config.bcm b/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-C32/td3-a7050cx3-32s-32x100G.config.bcm
index a575049dc..22088621c 100644
--- a/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-C32/td3-a7050cx3-32s-32x100G.config.bcm
+++ b/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-C32/td3-a7050cx3-32s-32x100G.config.bcm
@@ -5,6 +5,7 @@ host_as_route_disable=1
 use_all_splithorizon_groups=1
 riot_enable=1
 sai_tunnel_support=1
+sai_tunnel_underlay_route_mode=1
 riot_overlay_l3_intf_mem_size=4096
 riot_overlay_l3_egress_mem_size=32768
 l3_ecmp_levels=2
diff --git a/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-D48C8/td3-a7050cx3-32s-48x50G+8x100G.config.bcm b/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-D48C8/td3-a7050cx3-32s-48x50G+8x100G.config.bcm
index 68ae98280..aaad28895 100644
--- a/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-D48C8/td3-a7050cx3-32s-48x50G+8x100G.config.bcm
+++ b/device/arista/x86_64-arista_7050cx3_32s/Arista-7050CX3-32S-D48C8/td3-a7050cx3-32s-48x50G+8x100G.config.bcm
@@ -5,6 +5,7 @@ host_as_route_disable=1
 use_all_splithorizon_groups=1
 riot_enable=1
 sai_tunnel_support=1
+sai_tunnel_underlay_route_mode=1
 riot_overlay_l3_intf_mem_size=4096
 riot_overlay_l3_egress_mem_size=32768
 l3_ecmp_levels=2
diff --git a/device/arista/x86_64-arista_7050cx3_32s/td3-a7050cx3-32s-flex.config.bcm b/device/arista/x86_64-arista_7050cx3_32s/td3-a7050cx3-32s-flex.config.bcm
index fef962c85..70a579e01 100644
--- a/device/arista/x86_64-arista_7050cx3_32s/td3-a7050cx3-32s-flex.config.bcm
+++ b/device/arista/x86_64-arista_7050cx3_32s/td3-a7050cx3-32s-flex.config.bcm
@@ -397,6 +397,7 @@ robust_hash_disable_mpls=1
 robust_hash_disable_vlan=1
 sai_load_hw_config=/etc/bcm/flex/bcm56870_a0_premium_issu/b870.6.4.1/
 sai_tunnel_support=1
+sai_tunnel_underlay_route_mode=1
 serdes_core_rx_polarity_flip_physical{1}=0x8
 serdes_core_rx_polarity_flip_physical{5}=0x2
 serdes_core_rx_polarity_flip_physical{9}=0xc
diff --git a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-C64/config.bcm.j2 b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-C64/config.bcm.j2
index 9410a83b6..db5b2562c 100644
--- a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-C64/config.bcm.j2
+++ b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-C64/config.bcm.j2
@@ -12,6 +12,7 @@
 {%-         set switch_subtype = DEVICE_METADATA['localhost']['subtype'] -%}
 {%-         if 'dualtor' in switch_subtype.lower() %}
 {%-             set IPinIP_sock = 'sai_tunnel_support=1
+                                   sai_tunnel_underlay_route_mode=1
                                    host_as_route_disable=1
                                    l3_ecmp_levels=2' -%}
 {%-         endif %}
diff --git a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-D108C8/config.bcm.j2 b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-D108C8/config.bcm.j2
index d9d8347b5..70512203f 100644
--- a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-D108C8/config.bcm.j2
+++ b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-D108C8/config.bcm.j2
@@ -4,6 +4,7 @@
 {%-     set switch_subtype = DEVICE_METADATA['localhost']['subtype'] -%}
 {%-     if 'dualtor' in switch_subtype.lower() %}
 {%-         set IPinIP_sock = 'sai_tunnel_support=1
+                               sai_tunnel_underlay_route_mode=1
                                host_as_route_disable=1
                                l3_ecmp_levels=2' -%}
 {%-     endif %}
diff --git a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-Q64/config.bcm.j2 b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-Q64/config.bcm.j2
index de65d73d4..ce8efa857 100644
--- a/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-Q64/config.bcm.j2
+++ b/device/arista/x86_64-arista_7260cx3_64/Arista-7260CX3-Q64/config.bcm.j2
@@ -12,6 +12,7 @@
 {%-         set switch_subtype = DEVICE_METADATA['localhost']['subtype'] -%}
 {%-         if 'dualtor' in switch_subtype.lower() %}
 {%-             set IPinIP_sock = 'sai_tunnel_support=1
+                                   sai_tunnel_underlay_route_mode=1
                                    host_as_route_disable=1
                                    l3_ecmp_levels=2' -%}
 {%-         endif %}
diff --git a/src/sonic-device-data/tests/permitted_list b/src/sonic-device-data/tests/permitted_list
index c1f70dc7b..e1a651569 100644
--- a/src/sonic-device-data/tests/permitted_list
+++ b/src/sonic-device-data/tests/permitted_list
@@ -2,6 +2,7 @@ sai_trap_group_priority
 use_all_splithorizon_groups
 riot_enable
 sai_tunnel_support
+sai_tunnel_underlay_route_mode
 riot_overlay_l3_intf_mem_size
 riot_overlay_l3_egress_mem_size
 l3_ecmp_levels