diff --git a/gso/api/v1/network.py b/gso/api/v1/network.py
index 9109fd6fcde9ca14825b64d506082fb68037eb54..9b385c8e86330e5929a8e7b1a882faf07b966da0 100644
--- a/gso/api/v1/network.py
+++ b/gso/api/v1/network.py
@@ -62,6 +62,7 @@ class IptrunkBlock(OrchestratorBaseModel):
     iptrunk_capacity: str
     iptrunk_isis_metric: int
     iptrunk_sides: list[IptrunkSideBlock]
+    geant_s_sid: str
 
 
 class IptrunkSchema(OrchestratorBaseModel):
@@ -106,6 +107,7 @@ def network_topology() -> NetworkTopologyDomainModelSchema:
                 "iptrunk_capacity": _calculate_iptrunk_capacity(
                     extended_model["iptrunk"]["iptrunk_sides"], extended_model["iptrunk"]["iptrunk_speed"]
                 ),
+                "geant_s_sid": extended_model["iptrunk"]["geant_s_sid"],
                 "iptrunk_sides": [
                     {
                         "subscription_instance_id": side["subscription_instance_id"],