Re: TSV Area Review of draft-ietf-mboned-mtrace-v2

Hitoshi, Brian, *:

Wrt. mtrace v1:

mtrace-v2 should probably include a reference of draft-ietf-idmr-traceroute-ipm-07
as the latest specification available for mtrace-v1.

Wrt. comparison. I would add a sentence saying that implementations
of mtrace-v1 in Unix and router operating systems where/are not necessarily fully
compliant with that specification or each other, therefore a detailled list of
changes vs. mtrace-v1 serves no good purpose because there is no clear most
relevant target of comparison.

E.g: It is at least my good memory that i ran into inconsitencies/incompatibilities between
that draft, Unix mtrace and Cisco IOS mtrace.

It would make sense to extract the existing paragraph mentioning the "previous version",
put it together with the paragraph explaining the history and above notes into some new section
at the end with "mtrace version 1" in its title so that one can easier find this mtrace-v1 stuff,
because right now its somewhat hidden.  But don't spend too many cycles on it.

Cheers
    torless

On Thu, Jan 25, 2018 at 01:54:22PM +0900, Hitoshi Asaeda wrote:
> > 2018/01/24 18:47, Brian Trammell (IETF) <[email protected]> wrote:
> > One question: this may be a moot question (I did not review mtrace v1), but it appears that mtrace2 is designed to share a port with mtrace1, and I don't see any version field in the messages. How is version transition handled by this protocol? Is it possible to run a mixed network with both mtrace versions and have the right thing (probably downgrade) happen, or is the assumption that mtrace version migration is a flag day? A related editorial suggestion: a list of changes from mtrace v1 to mtrace v2 in an appendix would be useful.
> 
> There is no mtrace v1 specification. Some vendors and UNIX OSes implemented mtrace (aka mtrace ???v1???) without the standard specification. It was mentioned in section 10 (Acknowledgements) as follows;
> 
>    This specification started largely as a transcription of Van
>    Jacobson's slides from the 30th IETF, and the implementation in
>    mrouted 3.3 by Ajit Thyagarajan.  Van's original slides credit Steve
>    Casner, Steve Deering, Dino Farinacci and Deb Agrawal.  The original
>    multicast traceroute client, mtrace (version 1), has been implemented
>    by Ajit Thyagarajan, Steve Casner and Bill Fenner.
> 
> The problem is that since no standard specification, there is no interoperability with the different mtrace v1 implementations. Mtrace v1 is not only obsolete but also no specification; hence it is difficult or meaningless to clearly show the diffs between mtrace v1 and v2, IMO.
> 
> Regarding backward compatibility, as briefly mentioned in section 1 (as follows);
> 
>    Mtrace2 supports both IPv4 and IPv6.  Unlike the previous version of
>    Mtrace, which implements its query and response as Internet Group
>    Management Protocol (IGMP) messages [8], all Mtrace2 messages are
>    UDP-based.
> 
> mtrace v1 was implemented on top of IGMP, while mtrace v2 is defined with UDP. There is no compatibility between them, and the WG agreed on ignoring this compatibility.
> 
> Also it may be worth noting that we can handle new (e.g., v3) mtrace versions by supporting new TLV types, with downward compatibility provided for the mtrace2 TLV types at this moment.
> 
> Best regards,
> --
> Hitoshi Asaeda
> 
> 
> 
> 
> _______________________________________________
> MBONED mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/mboned

-- 
---
[email protected]

_______________________________________________
MBONED mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/mboned