Re: [Int-area] I-D Action: draft-ietf-intarea-gue-04.txt

Joe Touch <> Fri, 19 May 2017 21:41 UTC

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Subject: Re: [Int-area] I-D Action: draft-ietf-intarea-gue-04.txt
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It might be useful for this document to be more clear in showing

a) the specific header it introduces, before it talks about variations
(e.g. in Sec 2 when it is introduced, rather than in subsections)

b) examples of that header in the context they would appear in a typical
packet, clearly indicating the GUE portion as distinct from that context

The current explanation is a bit confusing because it uses atypical terms:

    - sec 2, what is a UDP/IP header? When we say TCP/IP, we mean the
protocol suite, not a header

        AFAICT, this should show UDP and IP as separate:
[IP][UDP][GUE][GUE payload]

    - sec 3.1, 4.1, and 4.2 present a header format in a confusing way

        GUE doesn't change the UDP header; it's a header inside UDP, so
the UDP part should be omitted (making it consistent with what I expect
for sec 2)

         the representation in 3.1 is confusing in comparison to 3.3.2,
which is just the GUE header (again, omitting UDP from 3.1, 4.1, and 4.2
fixes this)

Sec 4.1 should make it clear that the fields shown are just that of the
IPv4 header - and the fact that the first two bits are 01 is what helps
GUE realize that this is a special case.

Sec 4.2 should do the same for IPv6.

It seems like you also need to address what happens for IPv5, IPv7, and
later values of IP (i.e., 00 = GUE, 01=IPv4-7, and what happens for 1x?).


On 5/18/2017 3:53 PM, wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the Internet Area Working Group of the IETF.
>         Title           : Generic UDP Encapsulation
>         Authors         : Tom Herbert
>                           Lucy Yong
>                           Osama Zia
> 	Filename        : draft-ietf-intarea-gue-04.txt
> 	Pages           : 37
> 	Date            : 2017-05-18
> Abstract:
>    This specification describes Generic UDP Encapsulation (GUE), which
>    is a scheme for using UDP to encapsulate packets of different IP
>    protocols for transport across layer 3 networks. By encapsulating
>    packets in UDP, specialized capabilities in networking hardware for
>    efficient handling of UDP packets can be leveraged. GUE specifies
>    basic encapsulation methods upon which higher level constructs, such
>    as tunnels and overlay networks for network virtualization, can be
>    constructed. GUE is extensible by allowing optional data fields as
>    part of the encapsulation, and is generic in that it can encapsulate
>    packets of various IP protocols.
> The IETF datatracker status page for this draft is:
> There are also htmlized versions available at:
> A diff from the previous version is available at:
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at
> Internet-Drafts are also available by anonymous FTP at:
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