Subject: [lp-wan] Comments on draft-ietf-lpwan-ipv6-static-context-hc-05

From: "Prof. Diego Dujovne" <[email-masked]>
Date: Mon, 10 Jul 2017 16:27:37 +0200

Dear all,
              I attach below the comments on the SCHC draft
until the end of section 8. I will follow up with the rest of
the draft later.
Regards,

                               Diego

Abstract:

-"A common context stored in a LPWAN device and in the network is used."

Although this is still the Abstract, it is not clear how a common context
will
be stored in the network.

-"In most of the cases, IPv6/UDP headers are reduced to a small identifier
called Rule ID. But sometimes the SCHC header compression mechanisms will
not be enough to send the compressed packet in one L2 PDU, so the SCHC
Fragmentation protocol must be used when needed."

There is an intermediate condition where the rest of the headers can be
transmitted without changing using fragmentation.

-"Moreover, this document specifies fragmentation and reassembly mechanim
for SCHC"

"A fragmentation and reassembly mechaniSm"

- "information with LPWAN"

"information with  a WAN"

- "LPWAN Radio Network (RG)"

What is ithe G standing for?

- "A Matching Operator (MO) is the operator used to make the comparison
between the Field Value"

The Field Value is not defined in the terminology section

- "When doing compression from Dw to Up the SCHC C/D needs to find the
correct Rule to use by identifying its Dev-ID and the Rule-ID."

The direction indicator defines Dw when it signals an Downlink message, and
Up when it signals an Uplink message. What would be a compression from an
Downlink to an Uplink?

- "In the Up situation only the Rule-ID is used."

Does this mean that when a node communicates with the Gateway, only the
Rule-ID is used given that another form of ID is transmitted on the packet
on L2?  What if there is no device ID in the L2 layer?

- "Next, then the fields"

It is either Next or then.

-  "and the SCHC take next Rule."

"takes"

- "Otherwise the next rule is tested."

"Otherwise, "

-  "Decompession Actions"

Decompression

- "layer two"

Throughout the document, L2 is mentioned either in words or with the
acronym. It should be uniform.

- "A matching is obtained"

"A match is obtained"

- "target value", "TV", "Target Value"

One of the options should be chosen, it is not used uniformly on the
document.

- "compression of headers fields"

"compression of header fields"

- "TV OR received value"

should it be in capitals?

- "If the DiffServ field identified by the rest of the rule do not vary"

"If the DiffServ field identified by the rest of the rule does not vary"

- "CDA must be "not-sent."

Missing a "

- "the first one is to do not compressed the field and sends the original
value, or the second where the values can be computed by sending only the
LSB bits:"

"the first one is not to compress the field and send the original value, or
the second where the values can be computed by sending only the LSB bits:"

- "is not derivated from an"

"derived"

- "then the TV contains the list of possible IIDs,"

"then the TV contains the list of all possible IIDs,"

-- 
DIEGO DUJOVNE
Profesor Asociado
Escuela de Informática y Telecomunicaciones
Facultad de Ingeniería - Universidad Diego Portales - Chile
www.ingenieria.udp.cl
(56 2) 676 8125