++doc ++clean table

doc/plan.org

@@ -1546,7 +1546,7 @@ debug packets - analyse code - goto 1
  [21:26] line:~% sudo apt install thrift-compiler
  libnanomsg-dev libjudy-dev
 *** Performance comparison
-*** Challenges / Limitations in P4
+*** P4 Possible Improvements / Current Challenges / Limitations
 **** DONE cannot read key from table
 ***** log
 Key and mask for matching destination is in table. We need this
@@ -1653,7 +1653,11 @@ bad json:
 
 #+END_SRC
 
-**** Only one LPM key supported in tables (2019-03-23)
+**** DONE Only one LPM key supported in tables (2019-03-23)
+Priority support in ternary possible. Means rewriting for
+developers. Could possibly be supported by switching to ternary mode
+internally.
+
 #+BEGIN_SRC
 ../p4src/static-mapping.p4(121): error: MyIngress.nat64, Multiple LPM keys in table
     table nat64 {
@@ -1695,7 +1699,6 @@ I could work around this by using if(! .. .hit) { my_action(table_id)
       - switch/if in actions: with shadow tables
       - switch/if in apply block
 
-
 ***** log
  Imho, compiler should be able to unroll these to some degree.
 
@@ -1730,6 +1733,15 @@ I could work around this by using if(! .. .hit) { my_action(table_id)
          }
  #+END_SRC
 
+**** TODO Modules, OS
+Not addressed so far: how to create re-usable code fragments that can
+be plugged in easily. There could be a hypothetical "P4OS" that
+manages code fragments. This might include, but not limited to
+downloading (signed?) source code, managing dependencies similar to
+Linux package management, handling updates, etc.
+**** TODO Code sharing (controller, switch)
+Many constants double defined. Easy to make errors.
+
 *** Implementation limitations
 **** No fragmentation support (yet)
 **** No session handling (yet)

p4app/controller.py

@@ -249,6 +249,7 @@ class L2Controller(object):
             self.controller.table_add("v6_networks", "set_egress_port", [str(v6route['net'])], [str(v6route['port'])])
 
         self.controller.table_clear("v4_networks")
+        self.controller.table_clear("v4_arp")
         for v4route in self.v4_routes[self.mode]:
             self.controller.table_add("v4_networks", "set_egress_port", [str(v4route['net'])], [str(v4route['port'])])