Re: [tcpm] Definition of SMSS/RMSS in RFC5681 are inaccurate?!

[Joe Touch <[e-mail]>]

Hi, all,

On 7/26/2010 8:43 AM, Hagen Paul Pfeifer wrote:
>
> On Mon, 26 Jul 2010 14:33:26 +0200, Alexander Zimmermann wrote:
>
>> The size does not include the TCP/IP headers and options. This is wrong!
>> The options are the TCP/IP headers.
>
> Strange that nobody spotted this. "The options are the TCP/IP headers",
> what does this mean? draft-ietf-tcpm-tcpmss-03 should be mentioned instead:
>
>     The MSS value to be sent in an MSS option should be equal to the
>     effective MTU minus the fixed IP and TCP headers.

Some of us just spotted this, and you just typed faster than we did ;-)

Yes, RFC5681 is correct, and draft-ietf-tcpm-tcpmss intends to update 
RFC879 and RFC2385.

Note that RFC2385 is already obsoleted by RFC5925, which states:

    Please note that the use of TCP-AO does not affect TCP's advertised
    maximum segment size (MSS), as is the case for all TCP options
    [Bo09].

This statement is consistent with draft-ietf-tcpm-tcpmss, FWIW.

(Dave - does this mean that draft-ietf-tcpm-tcpmssSec 3.2 might include 
a note that it updates 2385 even though 2385 is obsoleted...?)

Joe