Proof using.
induction l; intros; simpl in *.
- intros. find_inversion. intuition.
- break_match. find_inversion.
find_insterU. find_insterU. conclude_using eauto.
omega.
Qed.

(* Specifications: *)
Lemma processPackets_ge_start :
forall n l n' l',
processPackets n l = (n', l') ->
forall p,
In p l' ->
n <= (tmNum (snd p)).