+ E receives ADD_HOST(C) from F, and notes that is is already known:
+ <insert solution here>
+ E receives ADD_HOST(A) from F, and notes that is is already known:
+ <insert solution here>
+ E receives ADD_HOST(B) from F, and notes that is is already known:
+ <insert solution here>
+
+ 4 A receives ADD_HOST(D) from B, and notes that it is already known:
+ <insert solution here>
+ A receives ADD_HOST(E) from B, and notes that it is already known:
+ <insert solution here>
+ A receives ADD_HOST(F) from B, and notes that it is already known:
+ <insert solution here>
+ F receives ADD_HOST(A) from E, and notes that it is already known:
+ <insert solution here>
+ F receives ADD_HOST(B) from E, and notes that it is already known:
+ <insert solution here>
+ F receives ADD_HOST(B) from E, and notes that it is already known:
+ <insert solution here>
+
+ ...
+
+1.2.1 Augmenting ADD_HOST
+-------------------------
+
+A solution would be to augment ADD_HOST with an extra parameter, the nexthop of
+the added host:
+
+ 3 B receives ADD_HOST(D,A) from A,
+ B sends ADD_HOST(D,A) to C
+ B receives ADD_HOST(E,D) from A:
+ B sends ADD_HOST(E,D) to C
+ B receives ADD_HOST(F,E) from A:
+ B sends ADD_HOST(F,E) to C
+ E receives ADD_HOST(A,D) from D:
+ E sends ADD_HOST(A,D) to F
+ E receives ADD_HOST(B,A) from D:
+ E sends ADD_HOST(B,A) to F
+ E receives ADD_HOST(C,B) from D:
+ E sends ADD_HOST(C,B) to F
+
+ B receives ADD_HOST(F,C) from C, and notes that F is already known:
+ <insert solution here>
+ B receives ADD_HOST(D,E) from C, and notes that D is already known:
+ <insert solution here>
+ B receives ADD_HOST(E,F) from C, and notes that E is already known:
+ <insert solution here>
+ E receives ADD_HOST(C,F) from F, and notes that C is already known:
+ <insert solution here>
+ E receives ADD_HOST(A,B) from F, and notes that A is already known:
+ <insert solution here>
+ E receives ADD_HOST(B,C) from F, and notes that B is already known:
+ <insert solution here>