Hi, are any more clarifications needed for the XRA header spec?
Best regards, Bruno 2017-12-12 11:17 GMT+01:00 Bruno Verstuyft <bruno.verstu...@gmail.com>: > > > 2017-12-11 22:31 GMT+01:00 Guy Harris <g...@alum.mit.edu>: > >> On Dec 5, 2017, at 4:47 AM, Bruno Verstuyft <bruno.verstu...@gmail.com> >> wrote: >> >> > 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. >> >> You might want to say "ID of downstream *logical* channel" in the remarks >> for "Downstream Channel ID"; the remarks for "Upstream Channel ID" already >> say "logical upstream channel" (is it best to say "logical XXX channel" or >> "XXX logical channel"?). >> > > In the DOCSIS specs, there is no occurence of the term downstream logical > channel, since there are only physical downstream channels. > In the upstream, a physical upstream channel (channel around a center > frequency) can be divided into multiple logical channels. This division is > time based. > More information can be found in 5.2.1.1.3.1 "Downstream Data Forwarding > in a MAC Domain" and 5.2.1.1.3.2 " Upstream Data Forwarding in a MAC > Domain" in the DOCSIS MULPI spec. > > It is best to say logical upstream channel, since this is the term used in > the DOCSIS specs. > > > >> >> >> 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. >> >> So those are the minislots from section 7.4.1 "Signal Processing >> Requirements" of the PHY specification? >> > > Yes, updated in the Xra Header spec. > >> >> >> 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. >> >> So to which symbol in the packet does that refer? >> > > The first symbol of the packet. Updated in the spec. > >> >> > 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. >> >> So your sniffer assigns the Burst IDs? >> >> There's a variable-length "Burst ID" field and a "Burst ID Reference" >> field. Does the "Burst ID" field contain a single burst ID? If so, to >> which burst was that ID assigned? And what does the "Burst ID Reference" >> field contain? >> >> Added extra explanation in the spec. > > >> >> Does the SID TLV contain the Service Identifier for the service flow in >> >> which the packet was sent? >> > >> > Yes >> >> You might want to spell out "Service Identifier" in the remarks. >> > > Updated in spec. > > >> >> >> Does the IUC TLV contain the Interval Usage Code for the burst if the >> >> packet is a burst? >> > >> > Yes >> > > You might want to spell out "Interval Usage Code" in the remarks. >> >> > Updated in spec > > _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
