timer note

chapter/layer3.tex

@@ -101,6 +101,8 @@ routers across non-backbone area}
 
 \subsection{Timers}
 
+By default a 10 second hello timer and 40 second dead timer\footnote{Dead timer should always be 4x the hello timer}
+
 \subsection{Filtering}
 
 \subsection[OSPF vs IS-IS]{OSPF versus IS-IS}