Re: [ippm] Review on draft-ietf-ippm-ioam-data-06
Anoop Ghanwani <anoop@alumni.duke.edu> Fri, 23 August 2019 22:02 UTC
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From: Anoop Ghanwani <anoop@alumni.duke.edu>
Date: Fri, 23 Aug 2019 15:02:23 -0700
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To: vijayr@arista.com
Cc: "Frank Brockners (fbrockne)" <fbrockne@cisco.com>, "draft-ietf-ippm-ioam-data@ietf.org" <draft-ietf-ippm-ioam-data@ietf.org>, IETF IPPM WG <ippm@ietf.org>, Hugh Holbrook <holbrook@arista.com>, "OU, Heidi" <heidi.ou@alibaba-inc.com>, Surendra Anubolu <surendra.anubolu@broadcom.com>
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Subject: Re: [ippm] Review on draft-ietf-ippm-ioam-data-06
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Hi Frank, As with Vijay, I am also interested in understanding the use of GRE for in-sequencing OAM. Do we end up needing an Ethertype for TCP/UDP? Thanks, Anoop On Thu, Aug 22, 2019 at 10:06 AM Vijay Rangarajan <vijayr= 40arista.com@dmarc.ietf.org> wrote: > Hi Frank: > Thanks, I knew I was missing something. > So basically what you are saying is - let's say we have a UDP packet, we > are just going to stick in the GRE header and IOAM Header and Metadata > in-between the original IP and UDP headers? > > So, the next protocol in the IOAM Header should indicate the L4 protocol - > i.e UDP/TCP? > Looking at https://datatracker.ietf.org/doc/draft-weis-ippm-ioam-eth/, it > actually defines the "Next protocol" in the IOAM header to be an ethertype > value? > > Thanks, > Vijay > > > On Thu, Aug 22, 2019 at 6:22 PM Frank Brockners (fbrockne) < > fbrockne@cisco.com> wrote: > >> Hi Vijay, >> >> >> >> note that you don’t necessarily need to “tunnel” – you can just use the >> GRE header to sequence-in IOAM. >> >> >> >> Cheers, Frank >> >> >> >> *From:* Vijay Rangarajan <vijayr@arista.com> >> *Sent:* Donnerstag, 22. August 2019 05:31 >> *To:* Carlos Pignataro (cpignata) <cpignata@cisco.com >> <cpignata@cisco..com>> >> *Cc:* Jai Kumar <jai.kumar@broadcom.com>; >> draft-ietf-ippm-ioam-data@ietf.org; IETF IPPM WG <ippm@ietf.org>; Frank >> Brockners (fbrockne) <fbrockne@cisco.com>; Hugh Holbrook < >> holbrook@arista.com>; Anoop Ghanwani <Anoop.Ghanwani@dell.com>; OU, >> Heidi <heidi.ou@alibaba-inc..com <heidi.ou@alibaba-inc.com>>; Surendra >> Anubolu <surendra.anubolu@broadcom.com>; John Lemon < >> john.lemon@broadcom.com> >> *Subject:* Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 >> >> >> >> Thanks Carlos, for pointing me to the draft. >> >> >> >> Based on my understanding of the two drafts I have the following >> questions and concerns: >> >> 1. If I understand correctly, to deploy inband telemetry, we would >> need to construct GRE tunnels coinciding with the IOAM domain? >> 2. GRE typically requires configuration to provision the tunnels. >> Provisioning and managing these tunnels and keeping these updated as the >> network grows/shrinks could be a significant overhead. >> 3. In order to get the benefit of telemetry, we are imposing a change >> in forwarding protocol/topology and configuration - which, I feel is not >> desirable. For example, a customer might have basic L3 routing enabled and >> the expectation would be for inband telemetry to work seamlessly, without >> having to revamp the network with GRE tunnels and such. This could be a >> significant barrier to deployment. >> 4. If sampling is used to select packets for performing IOAM encap, >> is the expectation that only sampled IOAM packets go through GRE encap? Or >> all data packets? >> 5. Due to network nodes inserting the IOAM data, the inner L3/L4 >> headers keep getting pushed deeper. I would imagine this gets challenging >> for ASICs to access these fields for hashing/load balancing. >> 6. Assuming only a subset of packets in a flow are subject to IOAM >> (based on sampling), how do we ensure these packets take the same network >> path as the rest of the packets in the flow? >> >> Thanks, >> >> Vijay >> >> >> >> >> >> On Wed, Aug 21, 2019 at 5:04 PM Carlos Pignataro (cpignata) < >> cpignata@cisco.com> wrote: >> >> Hello, Vijay, >> >> >> >> Please see https://datatracker.ietf.org/doc/draft-weis-ippm-ioam-eth/, >> and the document this replaces. >> >> >> >> Thanks! >> >> Thumb typed by Carlos Pignataro. >> >> Excuze typofraphicak errows >> >> >> 2019/08/21 6:35、Vijay Rangarajan <vijayr@arista.com>のメール: >> >> Hello all: >> >> Apologise if this has been previously discussed. >> >> In reading "draft-ietf-ippm-ioam-data-06", I don't see mention of GRE >> encap. The draft, in fact in Sec 3, says the following - "The in-situ OAM >> data field can be transported by a variety of transport protocols, >> including NSH, Segment Routing, Geneve, IPv6, or IPv4. Specification >> details for these different transport protocols are outside the scope of >> this document." >> >> >> >> Is there another document, or a description somewhere, that talks about >> how IOAM is proposed to be carried in GRE? what would be the GRE payload, >> the GRE protocol type etc? >> >> >> >> Thanks, >> >> Vijay >> >> >> >> >> >> On Wed, Aug 21, 2019 at 7:52 AM Jai Kumar <jai.kumar@broadcom.com> wrote: >> >> Hello Frank, >> >> >> >> This is in context of our conversation at IETF105. My goal is to provide >> input and improve current IOAM data draft with the learnings we had with >> IFA deployment. >> >> This feedback is based on various customer interactions and concerns >> raised by them wrt IOAM. Each feedback is a longer topic and I am starting >> this thread as a summary email. This is just highlighting the issues and >> not yet proposing any solution. >> >> >> >> >> >> Feedback 1: >> >> Section 4.2.1 Pre-allocated and Incremental Trace Options >> >> Pre-allocated and incremental trace option is 8Bytes long. This can be >> easily reduced to 4Bytes. >> >> There is a feedback that pre-allocated option is really not needed and >> either be removed or made optional. >> >> Given that deployments are sensitive to the IOAM overhead (specially in >> 5G deployments), it’s a 50% fixed overhead savings on a per packet basis. >> >> >> >> >> >> Feedback 2: >> Section 4.1 IOAM Namespaces >> >> Namespaces should be treated as templates (similar to IPFIX template >> record formats). This is more flexible way of enumerating data. 64K >> namespace id is a very large namespace and can be reduced to 64 IANA >> specified name spaces. Separate private name space can be allowed instead >> of interleaving of opaque data in the IANA allocated name space as >> suggested in the current draft “opaque state snapshot”. >> >> https://tools.ietf.org/html/rfc7011#section-3.4 >> >> >> >> Feedback 3: >> >> Section 4.2.1 Pre-allocated and Incremental Trace Options >> >> IOAM-Trace-Type: A 24-bit identifier which specifies which data >> >> types are used in this node data list. >> >> This is the most contentious of all. In the current proposal, as new data >> fields are added, there is a corresponding trace type bit need in the >> header. This essentially means that all possible data fields need to be >> enumerated. Given that we there are 64K names spaces allowed, I don’t see >> how we can fit all possible data fields in this 24bit vector. I know there >> was a suggestion of keeping last bit as an extension bit but it is still >> scalable and/or easy to implement in hardware. Besides this the data fields >> are not annotated/encoded with the data type, something like in IPFIX >> https://tools.ietf.org/html/rfc7011#section-6.1 >> >> >> >> Feedback 4: >> >> There is no version field in the data header and this will make >> interoperability challenging. Standard will evolve and headers bit >> definition and/or trace type will change and without version field HW will >> not be able to correctly handle the IOAM data headers. >> >> >> >> Feedback 5: >> >> Handling of TCP/UDP traffic using GRE encap is not acceptable. Here are >> some of the issues I can think of >> >> - GRE encaped IOAM packets will traverse a different network path >> then the original packet >> - Not all packets can be GRE encaped to avoid the previous problem, >> due to wastage of network bandwidth (typically sampled traffic is used for >> IOAM). What about native GRE traffic, will it get further encaped in >> another GRE tunnel and so forth. >> - IP header protocol will point to GRE IP proto and IOAM ethertype >> (pending allocation by IEEE) need to be read from the GRE header to detect >> an IOAM packet. This means parsing performance penalty for all regular GRE >> (non IOAM) traffic. >> >> >> >> Thanks, >> >> -Jai >> >> >> >> _______________________________________________ > ippm mailing list > ippm@ietf.org > https://www.ietf.org/mailman/listinfo/ippm >
- [ippm] Review on draft-ietf-ippm-ioam-data-06 Jai Kumar
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Carlos Pignataro (cpignata)
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Vijay Rangarajan
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Frank Brockners (fbrockne)
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Vijay Rangarajan
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 OU, Heidi
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tom Herbert
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 OU, Heidi
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tom Herbert
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Barak Gafni
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Anoop Ghanwani
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tom Herbert
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Greg Mirsky
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Jai Kumar
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Greg Mirsky
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tom Herbert
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tianran Zhou
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Tianran Zhou
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Anoop Ghanwani
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Jai Kumar
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Carlos Pignataro (cpignata)
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Frank Brockners (fbrockne)
- Re: [ippm] Review on draft-ietf-ippm-ioam-data-06 Anoop Ghanwani