While ns starts numbering
packets at 0, the SCTP module starts numbering DATA chunk TSNs at 1
and assigns undefined TSN values (-1) to control chunks (ie, INIT,
SACK, HEARTBEAT, etc). The four packets exchanged during the
association establishment are counted in the packet enumeration, but
do not show up in graphs. This information is important when doing
things like specifying a drop list for the ErrorModel
object. For example, packet 2 actually refers to the first SCTP
packet with DATA chunk(s).
Tom Henderson
2011-11-05
