Updated the specification with clarifications below. 2017-12-05 13:47 GMT+01:00 Bruno Verstuyft <bruno.verstu...@gmail.com>:
> > > 2017-12-04 22:21 GMT+01:00 Guy Harris <g...@alum.mit.edu>: > >> On Nov 16, 2017, at 1:21 AM, Bruno Verstuyft <bruno.verstu...@gmail.com> >> wrote: >> >> > we put the specification of the XRA header online. >> >> The MAC document speaks of "logical" upstream and downstream channels; >> are those what the "Downstream Channel ID" and "Upstream Channel ID" TLVs >> refer to? >> > Yes, from the MULPI spec: > Logical (Upstream) Channel: A MAC entity identified by a unique channel ID > and for which bandwidth is allocated by an > associated MAP message. A physical upstream channel may support multiple > logical upstream > channels. The associated UCD and MAP messages completely describe the > logical channel. > > 5.2.1.1.3.1 Downstream Data Forwarding in a MAC Domain: > A MAC Domain provides downstream DOCSIS data forwarding service using the > set of downstream channels > associated with the MAC Domain. Each downstream channel in a MAC Domain is > assigned an 8-bit Downstream > Channel ID (DCID). > > > >> >> To what do the start and stop minislots in the "Minislot ID" TLV refer? >> > > These are the minislots, relative in an OFDMA frame. The minislot with the > lowest subcarriers has id 0. > > >> >> What do the "Symbol ID", "Burst ID", and "Subplot ID" TLVs contain? >> > > Symbol ID is a number assigned to each symbol by our hardware. This is > mainly used for timing calculations. It can also be used to visualize the > correlation between NCP (Next Codeword Pointers) and the corresponding > downstream data packets. > > Burst ID is used to map mac frames to the corresponding databurst. A > databurst can e.g. contain a segment:(see MULPI 7.2.4 > Continuous Concatenation and Fragmentation). This means a segment can > contain multiple Mac frames, or a Mac frame can be spread over multiple > segments. In our sniffer, we extract these Mac frames from the segments. To > save the information of which Mac frame belongs to which segment (or > multiple segments), we use the Burst ID: each data burst gets a unique > Burst ID. In the Mac Frame the "Burst Info"/"Burst ID reference" is used to > reference these Burst IDs. > > Subslot ID: A minislot can be divided into multiple subslots to provide > multiple transmission opportunities for Bandwidth requests > (see PHY 8.2.4.1 Subslot Structure). This is the ID of this subslot. The > leftmost subslot has id 0. > > > > >> >> Does the SID TLV contain the Service Identifier for the service flow in >> which the packet was sent? >> > > Yes > >> >> Does the IUC TLV contain the Interval Usage Code for the burst if the >> packet is a burst? > > > Yes > > _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
