tools: Visualize per-face link-layer byte counts in nfd-status

refs #1768

Change-Id: Ic70567501903f6d386a9dc5fdc81e70eeb8c5fd7
diff --git a/docs/_static/nfd-status.xsd b/docs/_static/nfd-status.xsd
index 425bbd8..6a080a7 100644
--- a/docs/_static/nfd-status.xsd
+++ b/docs/_static/nfd-status.xsd
@@ -18,6 +18,13 @@
   </xs:sequence>
 </xs:complexType>
 
+<xs:complexType name="bidirectionalByteCountersType">
+  <xs:sequence>
+    <xs:element type="xs:nonNegativeInteger" name="incomingBytes"/>
+    <xs:element type="xs:nonNegativeInteger" name="outgoingBytes"/>
+  </xs:sequence>
+</xs:complexType>
+
 <xs:complexType name="generalStatusType">
   <xs:sequence>
     <xs:element type="xs:string" name="version"/>
@@ -59,6 +66,7 @@
     <xs:element type="xs:anyURI" name="localUri"/>
     <xs:element type="xs:duration" name="expirationPeriod" minOccurs="0"/>
     <xs:element type="nfd:bidirectionalPacketCountersType" name="packetCounters"/>
+    <xs:element type="nfd:bidirectionalByteCountersType" name="byteCounters"/>
     <xs:element type="nfd:faceFlagsType" name="flags" minOccurs="0"/>
   </xs:sequence>
 </xs:complexType>