Re: [tcpm] New version of TCP Option for Transparent Middlebox Discovery available

[Andrew Knutsen <andrew.knutsen at bluecoat.com>]

Joe Touch wrote:
> Simply stating that simultaneous open isn't supported is insufficient.
> The document needs to explain what happens when a SYN is received with
> the option when in the SYN-SENT state - i.e., what happens in response
> to the SYN received, and what happens if the other end responds to the
> option in the SYN that has been sent.
>
>
>   

   Thats why the following text is there:

5.2. Initiating Discovery Request

  Requests are only valid in SYN packets. They MUST NOT appear in other
  segments and MUST be ignored when found outside of a SYN.

5.3. Responding to Discovery Request

  Requests received in any state except SYN-SENT MUST be ignored.

  Responses are only valid in valid SYN-ACK packets. They MUST NOT
  appear in other segments and MUST be ignored when found outside of a
  SYN-ACK.

> FWIW, the text in the security considerations needs to take space into
> account as well

   Since the context of the connection impacts the space constraints, 
and that context depends on the device capability and changes over time, 
we feel these issues should be addressed in the specific capability 
specs.  Several vendors are using various forms of this option (with 
invalid kind codes) without problems. If space problems arise, we will 
all have to change our formats, as mentioned in the spec.  Perhaps if we 
adopt this draft, we can move away from the invalid codes at the same time.

Andrew