  Understanding transport capacity in intermittently connected mobile networks
(ICMN) is crucial since different applications have different interactivity and
bandwidth requirements. One practical issue is how to transform an
application's messages into packets suitable for transport over an ICMN. In
this paper, we propose a new Markovian model for random temporal graphs and
show, both analytically and by replaying a real life trace obtained in a
rollerblading tour, that the size of the messages sent over an ICMN has a
decisive impact on their delivery ratio. A given message could therefore be
broken down into smaller packets to increase reliability. However, we also show
that this gain in reliability only appears under tight constraints on the
maximum delay tolerated. Mobile application designers should therefore balance
message size against both application requirements and network topology
dynamics to improve performance.
