[ibr-dtn] Fragmentation and timestamp of bundles

I'm currently analysing bundle sending with wireshark, and I see that when a node is not a time reference, it sends bundles with timestamp 1 Jan 2000. These are accepted by another node, witch also is not a time reference. Are bundles with timestamp 1 Jan 2000 always accepted? How can fragmentation be made in ibrdtn with OpenWrt?