diff --git a/src/ncsi_util.hpp b/src/ncsi_util.hpp
index da45a38..a04e249 100644
--- a/src/ncsi_util.hpp
+++ b/src/ncsi_util.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <span>
+#include <string>
 
 namespace phosphor
 {
@@ -17,6 +18,8 @@
     int ifindex;
 };
 
+std::string to_string(Interface& interface);
+
 /* @brief  This function will ask underlying NCSI driver
  *         to send an OEM command (command type 0x50) with
  *         the specified payload as the OEM data.