Interest: Disallow zero-component Interest names

Change-Id: Ibe566428a5341eeea3da3ff0ab38254a90fddf98
Refs: #3781
diff --git a/interest.rst b/interest.rst
index 85449cb..85ce7be 100644
--- a/interest.rst
+++ b/interest.rst
@@ -30,6 +30,9 @@
 The Name element in an Interest is synonymous with the term *prefix*.
 See :ref:`Name section <Name>` for details.
 
+The Name element that can be put in the Interest is further restricted to have at least one NameComponent.
+Interests that include Name TLV that has zero name components MUST BE discarded.
+
 .. _Selectors:
 
 Selectors