Re: [Detnet] adoption of draft-dt-detnet-dp-alt-03?

[Jouni Korhonen <[e-mail]>]

Thanks Ethan,

I included the grammar corrections to the coming dp-alt-04. Others that
need more discussion are for later revisions.

- Jouni

On Thu, Sep 1, 2016 at 4:54 PM, Grossman, Ethan A. <[e-mail]> wrote:

> Yes I support the draft. This is a really well-crafted document, excellent
> work Jouni et al.
>
>
>
> As I was reading it I made a number of notes about mostly grammatical
> things that could/should be fixed, along with proposed text for each, and
> the occasional question about the intended meaning of a phrase. These are
> listed below.
>
>
>
> If you want, I could sign up to make these changes to the draft, but they
> would need to be proofread to make sure I didn’t misunderstand the ideas.
>
>
>
> My intent is not to nit pick, but I feel that a draft that has grammatical
> errors comes off as one that hasn’t yet had enough eyes on it, so I am
> trying to support credibility of the draft in my own simple way (i.e. I
> have nothing useful technical to say, I’m just learning from the draft).
>
>
>
> Sincerely,
>
> Ethan.
>
>
>
> --------------- Ethan’s comments on draft-dt-detnet-dp-alt-03
> -----------------
>
>
>
> p.4 - DetNet Transport Layer – “All DetNet nodes are end points and the
> transport layer.”
>
> ? What is this trying to say?
>
>
>
> 4.1. #1 Encapsulation and overhead: “In addition to the encapsulation
> mechanism this criteria is also concerned of the processing and
> specifically the encapsulate header overhead. “
>
> ? Fix grammar, e.g. “concerned with”, “encapsulation header”.
>
>
>
> 4.2. #2 Flow identification : “The flow identification can, for example, be
> explicit field in the data plane encapsulation header”
>
> ? Fix typo e.g. “be an explicit field”.
>
>
>
> 4.3. #3 Packet sequencing and duplicate elimination: “In addition to
> possible reordering packets other important uses for sequencing are
> detecting duplicates and lost packets.”
>
> ? Fix typo e.g. “reordering of packets,”.
>
>
>
> 4.6. #6 Operations, Administration and Maintenance: ”The solution
> alternative should demonstrate an availability of appropriate
> standardized OAM tools”
>
> ? Fix grammar e.g. “demonstrate availability”
>
>
>
> 4.7. #8 Class and quality of service capabilities: “Hereto, certain
> aspects of CoS and QoS may be provided by the underlying sub-net technology”
>
> ? Unusual language, suggest “For DetNet, certain aspects“
>
>
>
> 5.1.1.3. Summary: “IPv6 may be a choice as the DetNet Transport layer in
> networks where other technologies such as MPLS are not deployed.”
>
> ? Does this mean there will be multiple dataplane solutions? I thought the
> point was to choose one?
>
>
>
> 5.1.2.1. Solution description: “but these have historically not been
> supported on in hardware-based forwarding”
>
> ? Fix typo, e.g. “but historically these have not been supported in
> hardware-based forwarding”
>
>
>
> 5.1.3. Multiprotocol Label Switching (MPLS): “The remainder of this
> section will focus [RFC6373]. The remainder of this section will focus on
> the MPLS transport data plane, additional information on the MPLS service
> data plane can be found below”
>
> ? Consolidate these two sentences, or maybe clarify or eliminate first
> sentence?
>
>
>
> 5.1.3.2. Analysis and Discussion #1 Encapsulation and overhead (M): “The
> second perspective relates to encapsulation, if any, is needed to
> transport packets across network.”
>
> ? Fix grammar, e.g. “perspective relates to the encapsulation, if any,
> which is needed to transport packets across the network”
>
>
>
> 5.1.3.2. Analysis and Discussion #5 Flow duplication and merging: “there
> are mechanisms defined to provide 1+1 protection, which could help realizing
> the flow merging function
>
> ? Fix grammar e.g. “realize” or “in realizing”
>
>
>
> 5.1.4. Bit Indexed Explicit Replication (BIER)
>
> ? This section should be called “Bit Indexed Explicit Replication (BIER)
> over MPLS”, right? Otherwise it sounds like a competitor of ipv6, MPLS,
> etc.
>
>
>
> Ibid “the technology faces a lot of traction”
>
> ? “Facing” has negative connotation, you want something positive like “is
> getting a lot”
>
>
>
> Ibid. “Section 5.1.4 discusses the applicability of BIER for replication
> in the DetNet.”
>
> ? Fix wording, suggest “In the context of DetNet, BIER may be applicable
> for implementing packet replication, as described in section 5.1.4”.
>
>
>
> Ibid. “Bit-Indexed Explicit Replication (BIER) layer may be considered to
> be included into Deterministic Networking data plane solution.”
>
> ? No new information in this sentence, suggest deleting it.
>
>
>
> Ibid. “Encapsulation of a BIER packet in MPLS network presented in Figure
> 8”
>
> ? Fix grammar, suggest “The encapsulation of a BIER packet in an MPLS
> network is shown in Figure 8”
>
>
>
> 5.1.4.1. Solution description: “The DetNet may be presented in BIER as
> distinctive payload type with its own Proto(col) ID. Then it is likely that
> DetNet will have the header that would identify”
>
> ? Reword for clarity and to fix grammar, suggest “A distinctive BIER
> payload type (with its own Protocol ID) would be created for DetNet,
> providing a header that would identify:”
>
>
>
> Ibid. “DetNet node, collocated with BFIR, may use multiple BIER
> sub-domains to create replicated flows. Downstream DetNet nodes, collocated
> with BFER, would terminate redundant flows based on Sequence Number and/or
> Timestamp information. Such DetNet may be BFER in one BIER sub- domain and
> BFIR in another. Thus DetNet flow would traverse several BIER sub-domains.”
>
> ? ? Reword for clarity and to fix grammar, suggest “A DetNet node,
> collocated with a BFIR (Bit-Forwarding Ingress Router) may use multiple
> BIER sub-domains to create replicated flows. Downstream DetNet nodes,
> collocated with BFER (Bit-Forwarding Ingress Router) would terminate
> redundant flows based on Sequence Number and/or Timestamp information. Thus
> a DetNet node may be collocated with a BFER in one BIER sub- domain and
> with a BFIR in another, and a DetNet flow could traverse several BIER
> sub-domains.” [note: is “node” the right term here?]
>
>
>
> Ibid. “Consider DetNet flow”
>
> ? Fix grammar, suggest “Consider a DetNet flow”
>
>
>
> Ibid. “those that deemed too-late*”*
>
> ? Fix grammar, suggest “those that are deemed “too-late””.
>
>
>
> 5.1.4.2. Analysis and Discussion #1 Encapsulation and overhead: “(will
> refer as "BIER over MPLS" further for short), Figure 8, is being defined
> [I-D. ietf- bier-mpls-encapsulation]”
>
> ? Fix grammar, suggest “("BIER over MPLS")”
>
>
>
> Ibid. “[I-D. ietf- bier-mpls-encapsulation]”
>
> ? Fix ineffective link
>
>
>
> Ibid. “#5 Flow duplication and merging: “is core function”
>
> ? Fix grammar, e.g. “is a core function”.
>
>
>
> Ibid. #6: “Some OAM protocols, e.g. can be applied and used in BIER over
> MPLS as demonstrated [I-D.ooamdt-rtgwg-oam-gap-analysis], while new
> protocols being worked on”
>
> ? Fix grammar, e.g. “Existing OAM protocols can be applied and used in
> BIER over MPLS as demonstrated in [I-D.ooamdt-rtgwg-oam-gap-analysis],
> while new protocols are being worked on”
>
>
>
> Ibid. #8: “constrains”
>
> ? Fix spelling, “constraints”.
>
>
>
> Ibid. “calculating explicit path”
>
> ? Fix grammar, “calculating explicit paths”.
>
>
>
> 5.1.5.1. Solution description: “BIER-TE enables to activate”
>
> ? Fix grammar, suggest “enables activation of”
>
>
>
> Ibid. “Adversely”
>
> ? Wrong word, you mean “Conversely”.
>
>
>
> Ibid. “In more details”
>
> ? Fix grammar, “in more detail”
>
>
>
> Ibid. “BIER-TE also enables to detect the failing adjacencies”
>
> ? Fix grammar, e.g. “BIER-TE also enables detection of failing adjacencies”
>
>
>
> Ibid. “enables to avoid”
>
> ? Fix grammar, “enables avoiding”
>
>
>
> 5.1.5.2. Analysis and Discussion #5 Flow duplication and merging “M/W) The
> bitmap expresses in a very concise fashion which replication and merging
> (and elimination) should take place for a given packet. It also enables to
> control that process on a per packet basis, depending on the loss that it
> enables to measure.”
>
> ? Fix missing paren “(M/W)”.
>
> ? “enables to control” should be “enables controlling”.
>
> ? I don’t understand what this means “depending on the loss that it
> enables to measure” – please clarify.
>
>
>
> Ibid. #6: “enables to determine”
>
> ? Fix grammar, e.g. “enables determination of”
>
>
>
> Ibid. #9 Packet traceability (W): “enables to determine which is”
>
> ? Fix grammar, e.g. “enables determination of”
>
>
>
> Ibid. #10: “as is not fully defined.”
>
> ?Fix grammar, “and is not fully defined”.
>
>
>
> 5.1.5.3. Summary: “In the one hand it is optional, and only useful if
> replication and elimination is taking place. In the other hand,”
>
> ? Fix grammar, the expression is “On the one hand… on the other hand”.
>
>
>
> 5.2.2. MPLS-based Services for DetNet: “MPLS based technologies supports
> both the DetNet Service and DetNet Transport layers. This, as well as a
> general overview of MPLS, is covered above in Section 5.1.3.”
>
> ? Grammar: “supports” should be “support”.
>
>
>
> Ibid. “These sections focus on the DetNet Service Layer”
>
> ? Do you mean the previous sections or the following sections?
>
>
>
> Ibid. “it provides client service adaption, via Pseudowires”
>
> ? Not sure what you mean here. Is it “These sections focus on the DetNet
> Service Layer which provides client service adaption, via Pseudowires”?
>
>
>
> Ibid. “MPLS can thus also bounded by”
>
> ? Fix typo, “can thus also be bounded by”
>
>
>
> Ibid. “While MPLS service can provided on and true end-system to end-
> system basis,”
>
> ? Fix typo, suggest “on a true”
>
>
>
> 5.2.3.2. Analysis and Discussion #1 Encapsulation and overhead (M) “PWs
> offer encapsulation services practically for any types of payloads over any
> PSN”
>
> ? Fix grammar, e.g. “PWs offer encapsulation services for practically any
> type of payload over any PSN”
>
>
>
> Ibid. #2 Flow identification (M) “the MPLS PSN also uses one or more
> labels to transport packets over a specific label switched paths”.
>
> ? Fix grammar, I think you want “over specific label switched paths”
>
>
>
> Ibid. “#5 Flow duplication and merging (W) “transport leyer connection,
> though”
>
> ? Fix typo “layer”.
>
> ? Eliminate extra word “, though”.
>
>
>
> Ibid #6 “likewise IP PSN have the full toolbox”
>
> ? Fix typo “has the full toolbox”.
>
>
>
> Ibid. #8: “Due to the limited number of bits in the TC field, their use
> for QoS and ECN functions restricted and intended to be flexible.”
>
> ? Do you mean  “their use for QoS and ECN functions is restricted and is
> not intended to be flexible.”? Please fix wording.
>
>
>
> Ibid. #10 “already get close”
>
> ? Fix typo “already gets close”
>
>
>
> I am starting to understand that some networks support MPLS and some
> don’t, so if we depend on MPLS we have to have a backup plan for IP based
> networks. Is that correct? If so maybe that should be explained somewhere
> early on, to make it clear that more than one solution must be considered.
>
>
>
> 5.2.5.2.1. Solution Description: “transposting RTP header”
>
> ? should be “transporting RTP headers”, right?
>
>
>
> Ibid. “monitors of the data delivery”
>
> ? Fix typo “monitors the data delivery”
>
>
>
> 5.2.5.2.2 #2 Flow identification: “no two synchronization sources within
> the same RTP session has the same SSRC identifier”
>
> ? Fix grammar “have the same SSRC identifier”.
>
>
>
> ------------------------------------------------------------
> -------------------------------
>
>
>
> *From:* detnet [mailto:[e-mail]] *On Behalf Of *Pat Thaler
> *Sent:* Tuesday, August 23, 2016 11:08 AM
> *To:* [e-mail]
> *Subject:* Re: [Detnet] adoption of draft-dt-detnet-dp-alt-03?
>
>
>
> I mean Sept 5 - two week poll plus a bit since it was sent towards the end
> of a Friday.
>
>
>
> On Fri, Aug 19, 2016 at 11:53 AM, Pat Thaler <[e-mail]>
> wrote:
>
> All,
>
> This is start of a two-week poll on making
> draft-dt-detnet-dp-alt-03 a working group document. Please
> send email to the list indicating "yes/support" or "no/do not
> support". If indicating no, please state your reservations with the
> document.  If yes, please also feel free to provide comments you'd
> like to see addressed once the document is a WG document.
>
> The poll ends *Sept 5*, 2016
>
> Thanks,
>
> Pat Thaler
>
>
>
>
>



-- 
Jouni Korhonen, Broadcom Ltd.