diff --git a/src/sonic_ax_impl/mibs/ietf/rfc1213.py b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
index 1b09b0757..d853c26fc 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc1213.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
@@ -310,7 +310,7 @@ def if_index(self, sub_id):
         :return: the 0-based interface ID.
         """
         if sub_id:
-            return self.get_oid(sub_id) - 1
+            return self.get_oid(sub_id)
 
     def interface_description(self, sub_id):
         """