On Jul 18, 2008, at 9:47 AM, alex volinsky wrote:
DEPI works in two modes: D-MPT and PSP. In D-MPT mode, DOCSIS packets are encapsulated into MPEG2-TS fixed-size frames of 188 bytes. In one L2TPv3 payload, there could be from 1 to 7 MPEG2-TS frames. There is no length information in L2TPv3, so I'm looking into IP header.
As per other mail, the tvbuff that your dissector is handed has its own length information - in your dissector, call tvb_reported_length(tvb) to find out how much data is in the portion of the packet that your dissector is supposed to dissect.