+ 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, for example
+the host which told us about the new host. From A's point of view, D told it
+about itself, E and F. So, A would send out ADD_HOST(D, D) to B, and
+ADD_HOST(E,D) and ADD_HOST(F,D). Lets review what happens at point 3 in the
+preceding example:
+
+ 3 B receives ADD_HOST(D,D) from A,
+ B sends ADD_HOST(D,D) to C
+ B receives ADD_HOST(E,D) from A:
+ B sends ADD_HOST(E,D) to C
+ B receives ADD_HOST(F,D) from A:
+ B sends ADD_HOST(F,D) to C
+ E receives ADD_HOST(A,A) from D:
+ E sends ADD_HOST(A,A) to F
+ E receives ADD_HOST(B,A) from D:
+ E sends ADD_HOST(B,A) to F
+ E receives ADD_HOST(C,A) from D:
+ E sends ADD_HOST(C,A) to F
+
+ B receives ADD_HOST(F,F) from C, and notes that F is already known:
+ <insert solution here>
+ B receives ADD_HOST(D,F) 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,C) from F, and notes that C is already known:
+ <insert solution here>
+ E receives ADD_HOST(A,C) 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>