Can the transmitted data be lost in Digimesh?

Hi, I have a little question because I’m new in the Xbee & Digimesh world. I’m build my first mesh, I guess that I’m done it , but a question emerged me: What is the level of security in Digimesh or Zigbee protocol? , I mean exists an equivalent of TCP in Digimesh? That question that I do is because I need to consider if I must think in a some kind of security layer due to data lose in my software or this just is done by the Digimesh protocol or Zigbee.
Any kind of info is usefull to me.
Thanks!