diff --git a/proto/gosdn/pnd/pnd.proto b/proto/gosdn/pnd/pnd.proto
index 6bfb88a3ad442c81a35379effb3981465ae4f575..01a18db92d5bfcfc3510591e69dc16dfc0f03794 100644
--- a/proto/gosdn/pnd/pnd.proto
+++ b/proto/gosdn/pnd/pnd.proto
@@ -177,7 +177,7 @@ message GetSbiResponse {
   // TODO: Check if this is really needed. Perhaps a reference to the PND's ID
   // is also sufficient.
   PrincipalNetworkDomain pnd = 2;
-  .gosdn.southbound.SouthboundInterface sbi = 3;
+  repeated .gosdn.southbound.SouthboundInterface sbi = 3;
 }
 
 message GetSbiListResponse {