Per what I mentioned below - the below is my personal take, taking the position of a reader, who might not be aware of WG structures, WG scopes etc. Personally, I don't think that a reader of the SFC OAM framework document would expect the SFC WG to address all of the dimensions of SFC OAM, even if the document lays them out. That said, I do understand your concern about WG structures and scope. Looks like we (sadly) need to follow Conway's law ... So in general terms, I'm ok with Nagendra's approach. Cheers, Frank > -----Original Message----- > From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx> > Sent: Freitag, 22. Mai 2020 16:49 > To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar Nainar > (naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx > Cc: sfc@xxxxxxxx; last-call@xxxxxxxx; draft-ietf-sfc-oam-framework.all@xxxxxxxx > Subject: Re: Tsvart telechat review of draft-ietf-sfc-oam-framework-13 > > My basic concern is that if we go down the path you outline, it would suggest to > the reader that the SFC working group expected to address the SF dimensions of > the problem. I grant that they are real problems. But the SFC working group has > neither the charter nor the expertise to address those problems. As far as I can > tell, ART may have the expertise, and may not. And has shown no interest in the > problem. So I am very reluctant to put a lot of verbiage into the RFC on SF > monitoring. > > Given the above, can you live with Nagendra's text that you quote? > > Yours, > Joel > > On 5/22/2020 5:33 AM, Frank Brockners (fbrockne) wrote: > > Joel, > > > > Nagendra suggested "The task of evaluating the true availability of a > > Service Function is a complex activity, currently having no simple, > > unified solution. There is currently no standard means of doing so. > > Any such mechanism would be far from a typical OAM function, so it is > > not explored as part of the analysis in Sections 4 and 5." in the > > related thread for discussion on availability. > > https://mailarchive.ietf.org/arch/msg/sfc/1ZsLw6m1OeJRJfHW2TygxOyKPJk/ > > > > It could well be that my expectations for a framework document differ from > that of others. So please take this as a personal perspective. > > My expectation for a framework document is that it identifies and > > describes the components for a solution. It can optionally also hint > > at potential approaches to a solution (independently whether these > > solution are already in scope of the WG or not), but does not have to > > provide these solutions. The document does a good job at most of these > > - but misses out on those things, where we currently don't really have > > a solution available, which are questions like > > * How do we define availability for a SFC at service level? How do we define > availability for a SF? > > * How do we define performance for a SFC at service level? How do we define > performance for a SF? > > Right now the document focuses on those pieces of SF/SFC availability and > performance that are connectivity related ("Packets traverse it"). > > > > A potential approach could be to decompose the problem, using the structure > the document lays out - and put this into the context of SLA definitions. > > > > Why can we just say for e.g. SFC performance that SFC performance is a > > composite of > > * link layer performance, > > * underlay performance, > > * overlay performance, > > * service layer performance. > > A SFC OAM solution needs to consider the performance measures across all > those layers. > > Consequently, for the performance of a SF, one needs to consider the aspects > at each layer: > > * link layer - Example "how well is the SF connected at e.g. Ethernet > > layer?" -> example: Leverage ITU-T Y.1731 > > * underlay - Example "how well is the SF connected at e.g. IP layer?" > > -> example: Leverage OWAMP/TWAMP > > * overlay - Example "how well is the SF connected at e.g. NSH layer?" > > * service layer - Example "how well does the SF meet the criteria of an SLA?" > > So e.g. 3.1.2 and 3.2.2 could explicitly expand on these aspects and state that > apart from connectivity level measures (loss, throughput), service level criteria, > typically defined as part of an SLA, are included in SFC performance > characterization. IMHO this is a better approach, than either say "SF availability > is a hard problem" (which is what Nagendra says in the above statement - and > which is of course true) or just define the service aspects as out of scope for SFC > OAM ("how clean are the clothes when returned from the laundry?"). > > > > My 2cents.. > > > > Cheers, Frank > > > > > >> -----Original Message----- > >> From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx> > >> Sent: Mittwoch, 20. Mai 2020 20:17 > >> To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar > >> Nainar > >> (naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx > >> Cc: sfc@xxxxxxxx; last-call@xxxxxxxx; > >> draft-ietf-sfc-oam-framework.all@xxxxxxxx > >> Subject: Re: Tsvart telechat review of > >> draft-ietf-sfc-oam-framework-13 > >> > >> So the question now is whether the text Murray suggested suffices for > >> you? (We are still waiting to hear from Alvaro.) > >> > >> Yours, > >> Joel > >> > >> On 5/20/2020 1:41 PM, Frank Brockners (fbrockne) wrote: > >>> Thanks Joel. Per what I mentioned below, let's be clear that SF > >>> performance is > >> out of scope for the doc. > >>> And I think this was Alvaro's point as well. > >>> > >>> Cheers, Frank > >>> > >>>> -----Original Message----- > >>>> From: Joel M. Halpern <jmh@xxxxxxxxxxxxxxx> > >>>> Sent: Mittwoch, 20. Mai 2020 19:21 > >>>> To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; Nagendra Kumar > >>>> Nainar > >>>> (naikumar) <naikumar@xxxxxxxxx>; tsv-art@xxxxxxxx > >>>> Cc: sfc@xxxxxxxx; last-call@xxxxxxxx; > >>>> draft-ietf-sfc-oam-framework.all@xxxxxxxx > >>>> Subject: Re: Tsvart telechat review of > >>>> draft-ietf-sfc-oam-framework-13 > >>>> > >>>> Frank, regarding your comment about SF performance, I thought the > >>>> document was pretty clear that we consider that out of scope (c.f. > >>>> the discussions with the various ADs.) > >>>> > >>>> If you can see a place to add text, please propose text. > >>>> > >>>> Thank you, > >>>> Joel > >>>> > >>>> On 5/20/2020 1:10 PM, Frank Brockners (fbrockne) wrote: > >>>>> Hi Nagendra, > >>>>> > >>>>> Thanks for the detailed reply. Please see inline (..FB). > >>>>> > >>>>>> -----Original Message----- > >>>>>> From: Nagendra Kumar Nainar (naikumar) <naikumar@xxxxxxxxx> > >>>>>> Sent: Samstag, 16. Mai 2020 16:16 > >>>>>> To: Frank Brockners (fbrockne) <fbrockne@xxxxxxxxx>; > >>>>>> tsv-art@xxxxxxxx > >>>>>> Cc: sfc@xxxxxxxx; last-call@xxxxxxxx; > >>>>>> draft-ietf-sfc-oam-framework.all@xxxxxxxx > >>>>>> Subject: Re: Tsvart telechat review of > >>>>>> draft-ietf-sfc-oam-framework-13 > >>>>>> > >>>>>> Hi Frank, > >>>>>> > >>>>>> Thank you for the review. Please see inline for the response.. > >>>>>> > >>>>>> > >>>>>> Reviewer: Frank Brockners > >>>>>> Review result: Ready with Nits > >>>>>> > >>>>>> This document has been reviewed as part of the transport > >>>>>> area review > >>>> team's > >>>>>> ongoing effort to review key IETF documents. These > >>>>>> comments were > >>>> written > >>>>>> primarily for the transport area directors, but are copied > >>>>>> to the > >>>> document's > >>>>>> authors and WG to allow them to address any issues raised > >>>>>> and also to the IETF > >>>>>> discussion list for information. > >>>>>> > >>>>>> When done at the time of IETF Last Call, the authors > >>>>>> should consider > >> this > >>>>>> review as part of the last-call comments they receive. Please always > CC > >>>>>> tsv-art@xxxxxxxx if you reply to or forward this review. > >>>>>> > >>>>>> This document provides a reference framework for OAM for SFC. > >>>>>> > >>>>>> Comments: > >>>>>> > >>>>>> Section 3.1.1 SF availability: The text makes explicit > >>>>>> reference to > >> multiple > >>>>>> instances of a SF. Consequently, it should be defined how > >>>>>> availability of a > >>>> SF > >>>>>> is computed/determined in case multiple instances are deployed. > >>>>>> > >>>>>> <Nagendra> This is already clarified in the section as below: > >>>>>> > >>>>>> "For cases where > >>>>>> multiple instances of an SF are used to realize a given SF for the > >>>>>> purpose of load sharing, SF availability can be performed by checking > >>>>>> the availability of any one of those instances, or the availability > >>>>>> check may be targeted at a specific instance." > >>>>>> > >>>>>> This further > >>>>>> leads to the question, whether availability is always a "binary" state > >>>>>> (available / not-available), or could a SF be e.g. 99% available? > >>>>>> > >>>>>> <Nagendra>The availability is measured as binary state. I am not > >>>>>> sure what is 99% available. If it means getting 99 responses for > >>>>>> 100 probes sent, I think it falls under packet loss category > >>>>>> which in turn is > >>>> performance measurement. > >>>>> > >>>>> ...FB: Thanks. Though I'm still not entirely following. If > >>>>> availability is binary and > >>>> I put the statements above together, what would be the availability > >>>> of the following setup: There is an SF that is made up of 100 > >>>> instances. 99 of these instances are powered down entirely. And the > >>>> 1 instance that is "up" is alternating between servicing requests > >>>> for 10min followed by not servicing requests for 10min. Would the > >>>> SF be > >> considered "available"? > >>>>> > >>>>>> > >>>>>> Section 3.1.2 > >>>>>> SF performance: What is the impact of a "multiple instance > >>>>>> SF deployment" on SF > >>>>>> performance measurement? > >>>>>> > >>>>>> <Nagendra>I think we covered this in SF availability but not here. > >>>>>> Does the below updated text look better? > >>>>>> > >>>>>> OLD: > >>>>>> On the one hand, the performance of any specific SF can be quantified > >>>>>> by measuring the loss and delay metrics of the traffic from SFF to > >>>>>> the respective SF, while on the other hand, the performance can be > >>>>>> measured by leveraging the loss and delay metrics from the > respective > >>>>>> SFs. The latter requires SF involvement to perform the measurement > >>>>>> while the former does not. > >>>>>> > >>>>>> NEW: > >>>>>> On the one hand, the performance of any specific SF can be quantified > >>>>>> by measuring the loss and delay metrics of the traffic from SFF to > >>>>>> the respective SF, while on the other hand, the performance can be > >>>>>> measured by leveraging the loss and delay metrics from the > respective > >>>>>> SFs. The latter requires SF involvement to perform the measurement > >>>>>> while the former does not. For cases where > >>>>>> multiple instances of an SF are used to realize a given SF for the > >>>>>> purpose of load sharing, SF performance can be quantified by > measuring > >>>>>> the metrics for any one instance of SF or by measuring the metrics > for > >>>>>> a specific instance. > >>>>>> > >>>>>> The section only talks about loss and delay as > >>>>>> performance criteria. It would be good to state that other > >>>>>> performance criteria > >>>>>> (e.g. specific to the SF, throughput, etc.) exist. > >>>>>> > >>>>>> <Nagendra> We can add the below to Section 3.1.2: > >>>>>> > >>>>>> NEW: > >>>>>> "The metrics measured to quantify the performance of the SF > >>>>>> component is not just limited to loss and delay. Other metrics > >>>>>> such as throughout also exist and the choice of metrics for > >>>>>> performance measurement is outside the scope of this document." > >>>>>> > >>>>>> Section 3.2.1 SFC > >>>>>> availability: The current definition is very focused on connectivity > >>>>>> verification, i.e. it tries to answer the question: "Does my SFC > transport > >>>>>> packets?". IMHO we should also ask the question "Does my > >>>>>> SFC process > >>>> the > >>>>>> packets correctly?" - because if packets are not processed per the > SFC > >>>>>> definition, we might not call the SFC available. > >>>>>> > >>>>>> <Nagendra> I think this is already handled by SF availability. > >>>>>> The end-to-end SFC availability is verified by steering the OAM > >>>>>> packet over the ordered set of SFs within the SFC. This is more > >>>>>> like daisy chaining the availability of SFs within the SFC to > >>>>>> determine end-to-end SFC availability. If the derived solution > >>>>>> verifies the SF availability not just based on the uptime but > >>>>>> based on the service treatment, it also answers the question > >>>>>> "Does my SFC process the packets > >>>> correctly". Let us know if there is any further clarity required. > >>>>>> > >>>>>> While 3.2.2 states that "any > >>>>>> SFC-aware network device should have the ability to make > performance > >>>>>> measurements" a similar statement isn't found in 3.2.1. > >>>>>> IMHO the ability > >>>> for > >>>>>> availability checks is probably a prerequisite for > >>>>>> performance > >>>> measurement. > >>>>>> > >>>>>> <Nagendra> The ability to perform end-to-end or partial SFC > >>>>>> availability verification is already mentioned in section 3.2.1 as below: > >>>>>> > >>>>>> " In order to perform service connectivity verification of an SFC/SFP, > >>>>>> the OAM functions could be initiated from any SFC-aware network > >>>>>> devices of an SFC-enabled domain for end-to-end paths, or partial > >>>>>> paths terminating on a specific SF, within the SFC/SFP" > >>>>>> > >>>>>> Please let us know if you have any suggestion to improve if there > >>>>>> is a lack of clarity. > >>>>>> > >>>>>> Section 3.2.2 SFC performance measurement: The section > >>>>>> only mentions the need > >>>>>> for performance measurement. It misses the definition of > >>>>>> what SFC performance > >>>>>> measurement is. > >>>>>> > >>>>>> <Nagendra> > >>>>> > >>>>> ...FB: Thanks for the suggested updates, which would definitively > >>>>> improve the > >>>> text. One problem about SFC performance remains though IMHO. > >>>>> All the text so far is focused on the connectivity within a SFC - > >>>>> not the service > >>>> itself. I.e. If you'd consider a "laundry service" - we focus a lot > >>>> on how long it takes to get the clothes shipped to and from the > >>>> washing machine, but we don't focus on how well the washing machine > >> washes the clothes. > >>>>> IMHO we should either expand on the performance of the SFC and SF > >>>>> wrt/ the > >>>> service (especially given that you define a service layer in > >>>> section > >>>> 2) - or clearly state that the framework would just focus on > >>>> connectivity > >> between SFs. > >>>>> > >>>>> > >>>>>> > >>>>>> Section 3.3. Classifier component: The section mentions the > >>>>>> need for the ability to perform performance measurement of > >>>>>> the > >> classifier > >>>>>> component. What is performance measurement of the classifier? > >>>>>> What > >>>> does > >>>>>> performance measurement of the classifier component comprise? > >>>>>> > >>>>>> <Nagendra>We can add the below text: > >>>>>> > >>>>>> OLD: > >>>>>> Any SFC-aware network device should have the ability to perform > >>>>>> performance measurement of the classifier component for each SFC. > >>>>>> > >>>>>> NEW: > >>>>>> Any SFC-aware network device should have the ability to perform > >>>>>> performance measurement of the classifier component for each SFC. > >>>>>> The performance can be quantified by measuring the > >>>>>> performance metrics of the > >>>>>> traffic from the classifier for each SFC/SFP. > >>>>>> > >>>>>> Section 3.4. / > >>>>>> 3.5. Availability/PM of the underlay and overlay network: > >>>>>> It would be good > >>>> to > >>>>>> add a sentence that states that the mechanisms for > >>>>>> availability/PM which > >>>> are > >>>>>> offered by the technologies used by the overlay/underlay > >>>>>> are used, rather than > >>>>>> new methods specifically for SFC would be defined. > >>>>>> > >>>>>> <Nagendra>Yes, that makes sense. Please check the below text: > >>>>>> > >>>>>> OLD: > >>>>>> Any SFC-aware network device may have the ability to perform > >>>>>> availability check or performance measurement of the overlay > network. > >>>>>> > >>>>>> NEW: > >>>>>> Any SFC-aware network device may have the ability to perform > >>>>>> availability check or performance measurement of the overlay > network. > >>>> Any > >>>>>> existing OAM tools and techniques can be leveraged for this purpose. > >>>>>> > >>>>>> Section 4. SFC OAM > >>>>>> Functions: It would be good, if examples in section 4 > >>>>>> could also include > >>>> more > >>>>>> "recent" methods such as OWAMP/TWAMP (RFC4656, RFC 5357). > >>>>>> > >>>>>> <Nagendra> > >>>>>> > >>>>>> OLD: > >>>>>> Delay within an SFC could be measured based on the time it takes for > >>>>>> a packet to traverse the SFC from the ingress SFC node to the egress > >>>>>> SFF. As SFCs are unidirectional in nature, measurement of one-way > >>>>>> delay [RFC7679] is important. In order to measure one-way delay, > >>>>>> time synchronization MUST be supported by means such as NTP, PTP, > >>>>>> GPS, etc. > >>>>>> > >>>>>> NEW: > >>>>>> Delay within an SFC could be measured based on the time it takes for > >>>>>> a packet to traverse the SFC from the ingress SFC node to the egress > >>>>>> SFF. Measurement protocols such as One-way Active Measurement > >>>>>> Protocol (OWAMP) [RFC4656], Two-way Active Measurement > Protocol > >>>>>> (TWAMP) [RFC5357] can be used to measure the characteristics. As > >>>>>> SFCs are unidirectional in nature, measurement of one-way > >>>>>> delay [RFC7679] is important. In order to measure one-way delay, > >>>>>> time synchronization MUST be supported by means such as > >>>>>> NTP, Precision Time Protocol (PTP), > >>>>>> GPS, etc. > >>>>>> > >>>>>> Section 4.4. > >>>>>> Performance Measurement: Focus is entirely on the PM of > >>>>>> the > >>>> connectivity, > >>>>>> rather than on the SF. How about covering PM for the SF as well? > >>>>>> > >>>>>> <Nagendra> I am not sure I understand what is missing. Do you > >>>>>> have any suggestion for the text improvement?. > >>>>> > >>>>> ...FB: See above. This would be about adding a capability to > >>>>> assess how well > >>>> the washing machine washes my laundry. > >>>>> > >>>>>> > >>>>>> Section 5.1 > >>>>>> OAM Tool Gap Analysis: > >>>>>> - Not sure what "NVo3 OAM" refers to. Could that be > >>>>>> explained below the table > >>>>>> and in section 1.2.1? > >>>>>> > >>>>>> <Nagendra> Combining this with other below queries as they > >>>>>> appears to be related. > >>>>>> > >>>>>> - E-OAM needs to be detailed. Is seems that CFM > >>>>>> (802.1ag) and not 802.3ah is refered to here. > >>>>>> > >>>>>> <Nagendra> Per my understanding, 802.ah is 1-hop while 802.3ag > >>>>>> can be more than 1 hop and both uses Ethernet frames. So I think > >>>>>> both are > >>>> applicable here. > >>>>>> My response regarding E-OAM details in this section is combined below. > >>>>> > >>>>> ...FB: Maybe I missed it - but I don't see text that refers to CFM > >>>>> or EFM > >> OAM. > >>>> Where is this covered? IMHO we would need references to IEEE > >>>> standards to avoid confusion. > >>>>> > >>>>>> > >>>>>> - "Trace" in the "Trace" column > >>>>>> need to be extended on. Is this traceroute? Paris-Traceroute? > >>>>>> IOAM- Loopback? > >>>>>> > >>>>>> IPPM needs to be detailed, because IPPM is not a tool as > >>>>>> such but an IETF WG. > >>>>>> Does this refer to OWAMP/TWAMP/etc. as defined by IPPM? > >>>>>> > >>>>>> <Nagendra> Combining the above queries. > >>>>>> > >>>>>> OLD: > >>>>>> There are various OAM tool sets available to perform OAM functions > >>>>>> within various layers. These OAM functions may be used to validate > >>>>>> some of the underlay and overlay networks. Tools like ping and trace > >>>>>> are in existence to perform connectivity check and tracing of > >>>>>> intermediate hops in a network. These tools support different > >>>>>> network types like IP, MPLS, TRILL, etc. There is also an effort to > >>>>>> extend the tool set to provide connectivity and continuity checks > >>>>>> within overlay networks. BFD is another tool which helps in > >>>>>> detecting data forwarding failures. Table 3 below is not > >>>>>> exhaustive > >>>>>> > >>>>>> NEW: > >>>>>> There are various OAM tool sets available to perform OAM functions > >>>>>> within various layers. These OAM functions may be used to validate > >>>>>> some of the underlay and overlay networks. Tools like ping and trace > >>>>>> are used to perform connectivity check and tracing of > >>>>>> intermediate hops in a network. These tools are already available for > >>>>>> different types of networks such as IP, MPLS, TRILL, etc. > >>>>>> > >>>>>> E-OAM offers OAM mechanisms such as an Ethernet continuity check > >>>>>> for Ethernet links. There is an effort around NVO3 OAM to provide > >>>>>> connectivity and continuity checks for networks that use NVO3. > >>>>>> BFD is used for the detection of data plane forwarding failures. > >>>>> > >>>>> ...FB: Check whether NVO3 WG will indeed deliver a solution and > >>>>> "NVO3 > >> OAM" > >>>> indeed existis. If in doubt, it might be better to avoid forward > >>>> looking references. Per my note above, it would be good to > >>>> explicitly refer to IEEE standards as opposed to introducing a new term like > "E-OAM". > >>>>> > >>>>>> > >>>>>> The IPPM framework [RFC 2330] offers tools such as OWAMP > >>>>>> [RFC4656] and TWAMP [RFC5357] (collectively referred as IPPM in > >>>>>> this section) to measure various performance metrics. MPLS Packet > >>>>>> Loss Measurement > >>>>>> (LM) and Packet Delay Measurement (DM) (collectively referred as > >>>>>> MPLS_PM in this section) [RFC6374] offers the ability to measure > >>>> performance metrics in MPLS network. > >>>>>> > >>>>>> Table 3 below is not exhaustive. > >>>>>> > >>>>>> Section 6.4.3 IOAM: > >>>>>> - The section states that IOAM "may be used to perform > >>>>>> various SFC > >> OAM > >>>>>> functions as well". It would be good to expand on this statement: > E.g. > >>>> IOAM > >>>>>> Trace-Option Type could be leveraged for SFC tracing. IOAM > >>>>>> Direct-Export Option > >>>>>> Type could be leveraged. - How would we deal with the IOAM > >>>>>> Active > >> Flag > >>>>>> (draft-ietf-ippm-ioam-flags-01) when used with SFC OAM? > >>>>>> > >>>>>> <Nagendra> The intention of the section is to highlight the > >>>>>> applicability of different OAM toolsets for OAM functions at > >>>>>> service layer. I am not sure if we really should try explaining > >>>>>> all the possible options within each tool. But I agree that it is > >>>>>> worth clarifying the availability of IOAM options for tracing. > >>>>>> think we can clarify that different IOAM Option-Types are > >>>>>> available for OAM functions > >>>> such as SFC tracing. Can you check if the below looks ok? > >>>>>> > >>>>>> OLD: > >>>>>> [I-D.ietf-sfc-ioam-nsh] defines how In-Situ OAM data fields are > >>>>>> transported using NSH header. [I-D.ietf-sfc-proof-of-transit] > >>>>>> defines a mechanism to perform proof of transit to securely verify if > >>>>>> a packet traversed the relevant SFP or SFC. While the mechanism is > >>>>>> defined inband (i.e., it will be included in data packets), it may be > >>>>>> used to perform various SFC OAM functions as well. > >>>>>> > >>>>>> NEW: > >>>>>> [I-D.ietf-sfc-ioam-nsh] defines how In-Situ OAM data fields are > >>>>>> transported using NSH header. [I-D.ietf-sfc-proof-of-transit] > >>>>>> defines a mechanism to perform proof of transit to securely verify if > >>>>>> a packet traversed the relevant SFP or SFC. While the mechanism is > >>>>>> defined inband (i.e., it will be included in data packets), > >>>>>> IOAM Option- > >> Types > >>>>>> such as IOAM Trace Option-Types can also be used to perform > >>>>>> other SFC OAM function > >>>>>> such as SFC tracing. > >>>>>> > >>>>>> - The text states > >>>>>> "In-Situ OAM could be used with O bit set": Why would IOAM > >>>>>> be used with > >>>> the > >>>>>> overflow bit set for SFC OAM? For details on IOAM's O-bit, > >>>>>> see section > >>>> 4.4.1 in > >>>>>> https://tools.ietf.org/html/draft-ietf-ippm-ioam-data-09. > >>>>>> > >>>>>> <Nagendra> The O bit referred here is not the O bit in IOAM but > >>>>>> the one in NSH/Overlay header. To avoid any confusion, this can > >>>>>> be updated as > >>>> below: > >>>>>> > >>>>>> OLD: > >>>>>> In-Situ OAM could be used with O bit set to perform SF availability > >>>>>> and SFC availability or performance measurement. > >>>>>> > >>>>>> NEW: > >>>>>> In-Situ OAM could be used with O bit in the overlay header set, > >>>>>> to perform SF availability > >>>>>> and SFC availability or performance measurement. > >>>>> > >>>>> ... FB: Ah, ok. Given that this section is about IOAM and not NSH, > >>>>> I'd rather > >>>> explicitly refer to NSH here. E.g. If SFC is realized using NSH, > >>>> then the O-bit in the NSH header could be used to indicated OAM traffic. > >>>> You could refer to > >>>> https://tools.ietf.org/html/draft-ietf-sfc-ioam-nsh-03#section-4.2 > explicitly. > >>>>> > >>>>>> > >>>>>> Section 6.4.4 SFC > >>>>>> Traceroute: - This section refers to an expired draft > >>>>>> (even calling out > >> the > >>>>>> fact that the draft has exipred), but also mentions that functionality > is > >>>>>> available and implemented in OpenDaylight. Consider > >>>>>> removing the references to > >>>>>> the expired draft and rather add references to > >>>>>> OpenDaylight documents. - IOAM > >>>>>> Loopback (see draft-ietf-ippm-ioam-flags-01) could apply > >>>>>> SFC Traceroute as well. > >>>>>> > >>>>>> <Nagendra>Ok. Let me check if I can find some reference for ODL. > >>>>>> > >>>>>> Detailed set of nits that I encountered while reading > >>>>>> through the document ([x] > >>>>>> references line number x) – hope that they are helpful in > >>>>>> further improving > >>>> the > >>>>>> doc: > >>>>>> > >>>>>> <Nagendra> Yes of course (. > >>>>>> > >>>>>> [global] s/an SF/a SF/ -- and similarly SFC/SFF > >>>>>> > >>>>>> <Nagendra>Other RFCs uses "an SF/SFF". So the draft is updated > >>>>>> accordingly. If your suggestion is to substitute "a SF" to "an > >>>>>> SF", it is done > >> (. > >>>>>> > >>>>>> [176] "OAM Controller" not defined > >>>>>> > >>>>>> <Nagendra>We can change it as below: > >>>>>> > >>>>>> OLD: > >>>>>> OAM controllers are assumed to be within the same administrative > >>>>>> domain as the target SFC enabled domain. > >>>>>> > >>>>>> NEW: > >>>>>> OAM controllers are SFC-aware network devices that are capable of > >>>>>> generating OAM packets. They are assumed to be within the same > >>>>>> administrative domain as the target SFC enabled domain. > >>>>>> > >>>>>> [202] Why just Virtual Machines and no containers? Suggest > >>>>>> to make > >>>> things > >>>>>> generic and talk about virtual and physical entities. > >>>>>> > >>>>>> <Nagendra> We changed this as virtual entities. > >>>>>> > >>>>>> This comment applies throughout the document. > >>>>>> [216] Ethernet OAM: Add reference. Do you refer to > >>>>>> physical layer Ethernet OAM > >>>>>> (802.3ah) or CFM (802.1ag)? > >>>>>> > >>>>>> <Nagendra> The response was provided in the above comment section. > >>>>>> > >>>>>> [243] s/uses the overlay network/uses the overlay > >>>>>> network layer/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [246] Could we add a few examples of "various overlay network > >>>>>> technologies"? For the underlay network layer several > >>>>>> examples are > >> listed. > >>>>>> > >>>>>> <Nagendra> Ok. > >>>>>> > >>>>>> [248] What does "mostly transparent" mean? > >>>>>> > >>>>>> <Nagendra> The data plane elements connecting the overlay layer > >>>>>> nodes may not always process the overlay header. > >>>>> > >>>>> ...FB: How about we explain this in the document? > >>>>> > >>>>>> > >>>>>> [254] What does "tight coupling" > >>>>>> between the link layer and the physical technology mean? > >>>>>> > >>>>>> <Nagendra>I am not sure I understand the nit here. Do you see any > >>>>>> difficulty in parsing the sentence? > >>>>> > >>>>> ...FB: Not sure what "tight coupling" means here. Could you > >>>>> clarify what is > >>>> "tight coupling" vs. "not tight coupling"? > >>>>> > >>>>>> > >>>>>> [255] Suggest to avoid > >>>>>> terms like "popular" - popularity can change, standards > >>>>>> stay > >>>>>> > >>>>>> <Nagendra> Ok. This is changed as "Ethernet is one such choice..." > >>>>>> > >>>>>> [256] Acronyms > >>>>>> "POS" and "DWDM" are not defined > >>>>>> > >>>>>> <Nagendra> Added. > >>>>>> > >>>>>> [274] Link start/end-points don't seem to > >>>>>> always align with the underlay network in the diagram > >>>>>> > >>>>>> <Nagendra> Fixed it. > >>>>>> > >>>>>> [287] s/may comprise > >>>>>> of/may consist of/ > >>>>>> > >>>>>> <Nagendra>We fixed it as "may comprise".. > >>>>>> > >>>>>> [288] s/but not shown/but is not shown/ > >>>>>> > >>>>>> <Nagendra> We fixed this as "intermediate nodes not shown...: > >>>>>> > >>>>>> [307] > >>>>>> s/devices/device/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [308] What is a "controller"? > >>>>>> > >>>>>> <Nagendra> We discussed this in the above comment section. > >>>>>> > >>>>>> [314] s/includes/include/ > >>>>>> > >>>>>> <Nagendra>Done. > >>>>>> > >>>>>> [319] > >>>>>> Add hSFC to list of acronyms in section 1.2.1 > >>>>>> > >>>>>> <Nagendra> This is expanded in the respective section. We added > >>>>>> it in the acronym section as well. > >>>>>> > >>>>>> [320] Add IBN to list of acronyms > >>>>>> in section 1.2.1 > >>>>>> > >>>>>> <Nagendra> Ok, Done. > >>>>>> > >>>>>> [325] s/includes/include/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> [359] The function/term "controller" > >>>>>> requires definition. > >>>>>> > >>>>>> <Nagendra> Done, as mentioned in the above comment section. > >>>>>> > >>>>>> [383] s/?./?/ > >>>>>> > >>>>>> [398] s/get the got/got/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [461] > >>>>>> s/devices/device/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [469] Does it have to be equal cost multipath at the service > >>>>>> layer, or could unequal cost multipath also be an option > >>>>>> for > >>>>>> load- > >>>> balancing? > >>>>>> > >>>>>> <Nagendra>I didn’t see any discussion specific to ECMP/UCMP in > >>>>>> the architecture RFC. > >>>>> > >>>>> ...FB: Hmm. I did not see that RFC7665 is only about equal cost multipath. > >>>>>> > >>>>>> [521] Not sure whether the overlay network establishes the > >>>>>> service > >> plane. > >>>> Isn't > >>>>>> it that the overlay network establishes connectivity for the SFC- > related > >>>>>> functions in the service plane? > >>>>>> > >>>>>> <Nagendra> The service layer is established over the overlay > >>>>>> network layer. I am not sure if it is right to say overlay > >>>>>> network provides connectivity for service layer (. > >>>>> > >>>>> ...FB: Overlay network is one component of the service layer, > >>>>> isn't it. So it is > >>>> required but not sufficient. > >>>>> > >>>>>> > >>>>>> [531] s/components/component/ [545] remove > >>>>>> "underlay" > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [595] s/devices/device/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [600] s/action/an action/ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [601] Expand on > >>>>>> "TTL or other means" (TTL also needs to be added to > >>>>>> acronyms in 1.2.1). Is > >>>> this > >>>>>> specific to NSH? Or specific to IPv4? > >>>>>> > >>>>>> <Nagendra> TTL is listed as well-known abbrev in https://www.rfc- > >>>>>> editor.org/materials/abbrev.expansion.txt and so we left it as it is. > >>>>>> TTL in this document refers to NSH TTL field. > >>>>> > >>>>> ...FB: Let's ensure we refer to NSH TTL in this case. Given that > >>>>> SFC can be done > >>>> with other means than NSH, implicit reference to NSH might be a problem. > >>>>>> > >>>>>> [630] Mention that for "approximation of > >>>>>> packet loss for a given SFC can be derived" to be > >>>>>> applicable, SFC OAM > >>>> packets > >>>>>> would need to be forwarded the same as live user traffic. > >>>>>> > >>>>>> <Nagendra> As it is intending to derive the approximate loss > >>>>>> value, I am not sure if we need this additional consideration > >>>>>> that the OAM packet would need to follow the live user traffic. > >>>>>> Let me know if you think > >>>> otherwise. > >>>>> > >>>>> ...FB: IMHO we should - given that it is one potential complication. > >>>>> > >>>>>> > >>>>>> [636] Is uppercase > >>>>>> "MUST" applicable to an informational document? Especially given > that > >>>>>> RFC2119/RFC8174 is explicitly referenced by the draft. > >>>>>> > >>>>>> <Nagendra> Based on various reviewer comments, we removed the use > >>>>>> of any normative statement. > >>>>>> > >>>>>> [666] Add MPLS, TRILL to > >>>>>> acronyms in 1.2.1 > >>>>>> > >>>>>> <Nagendra> Ok. Done. > >>>>>> > >>>>>> [678] s/exhaustive/exhaustive./ > >>>>>> > >>>>>> <Nagendra> Done. > >>>>>> > >>>>>> [720] Is uppercase "SHOULD" applicable to an informational document? > >>>>>> Especially given that RFC2119/RFC8174 is explicitly > >>>>>> referenced by the > >>>> draft. > >>>>>> > >>>>>> <Nagendra> Based on various reviewer comments, we removed the use > >>>>>> of any normative statement. > >>>>>> > >>>>>> [722] Is uppercase "MAY" applicable to an informational document? > >>>> Especially > >>>>>> given that RFC2119/RFC8174 is explicitly referenced by the draft. > >>>>>> > >>>>>> <Nagendra> Based on various reviewer comments, we removed the use > >>>>>> of any normative statement. > >>>>>> > >>>>>> [754] > >>>>>> s/packet/packets/ > >>>>>> > >>>>>> [755] s/to next node/to the next node/ > >>>>>> > >>>>>> [771] How does this > >>>>>> requirement align with the earlier paragraph, e.g. in case > >>>>>> a node sends an ICMP > >>>>>> reply? It would probably make sense to scope the statement to e.g. > >> NSH. > >>>>>> > >>>>>> <Nagendra> As mentioned in the statement, the node that initiates > >>>>>> the OAM packet must set the marker and so this statement is > >>>>>> applicable for the initiating node. > >>>>>> > >>>>>> [806] > >>>>>> s/function/functions/ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [809] s/from relevant node/from the relevant node/ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [810] > >>>>>> s/generate ICMP/generate an ICMP/ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [812] s/from last/from the last/ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [830] > >>>>>> s/perform continuity/perform the continuity/ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [834] s/with relevant/with the > >>>>>> relevant > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [835] s/perform partial SFC availability./perform a partial SFC > >>>>>> availability check./ > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [851] For "In-Situ OAM data fields" add a normative > >>>>>> reference to draft-ietf-ippm-ioam-data > >>>>>> > >>>>>> [905] Add "CLI" to section 1.2.1 > >>>>>> acronyms > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> [920] Add a reference for NETCONF ->RFC6241 > >>>>>> > >>>>>> <Nagendra> Done > >>>>>> > >>>>>> Once again, thanks a lot for the great comments. > >>>>>> > >>>>>> Regards, > >>>>>> Nagendra > >>>>> > >>>>> Thanks again for considering the comments in great detail. Much > >> appreciated. > >>>>> > >>>>> Cheers, Frank > >>>>>> > >>>>>> > >>>>>> > >>>>> -- last-call mailing list last-call@xxxxxxxx https://www.ietf.org/mailman/listinfo/last-call
