Update ietf-layer0-types.yang

ietf-layer0-types.yang

@@ -89,7 +89,12 @@ module ietf-layer0-types {
       The nominal central frequency, 'f' is defined by,
         f = 193100.000 GHz + N x channel-spacing (measured in GHz),
       where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor 
-      frequency' for transmission over the C band.    ";
+        frequency' for transmission over the C band; and
+      where 'channel-spacing' is defined by the flexi-ch-spc-type.
+      
+      Note that the term 'chanel-spacing' can be alternated by the
+      term 'nominal central frequency granularity' defined in
+      clause 7 of ITU-T G.694.1.";
     reference
       "RFC7698: Framework and Requirements for GMPLS-Based Control
       of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)