Re: [middisc] TCP middlebox option requirements

Two additional issues seem worth clarifying since I'm not sure how others would view them.

1. Are we concerned strictly with autodiscovery options, or are we attempting to understand the requirements for options usage generally among current symmetric middleboxes?  For example, Riverbed uses a different option for some forms of addressing information in situations after the two communicating peers have been established by autodiscovery.  It wouldn't surprise me to learn that other vendors have other similar schemes.

2. Don't we also need to consider requirements for autodiscovery options in IPv6 environments?  

In both cases, I can see a pragmatic argument for focusing narrowly vs. an architectural argument for considering broader issues. IPv4 autodiscovery is the clear existing interoperability/coexistence problem and may be solvable by simply agreeing on an option number and vendor id scheme, while the other areas might not yet have enough experience and implementations to justify a standard.  And yet it feels to me like we might solve one option-related problem just to trip across another similar one soon afterward.

--Mark

-----Original Message-----
From: middisc-bounces@ietf.org [mailto:middisc-bounces@ietf.org] On Behalf Of Andrew Knutsen
Sent: Friday, May 21, 2010 2:23 PM
To: middisc@ietf.org
Subject: Re: [middisc] TCP middlebox option requirements

    Thanks Ananth.

    One possibility that Jamshid and I talked about addresses concerns 
about using 3 bytes for the OUI. We could skip it (and the P bit), and 
break up the 15 bits or so of "device capability" into an IANA-assigned 
vendor code of maybe 7 bits, leaving 8 bits (or so) for vendor-specific 
type. There could be one or more "standard" vendor codes for 
multi-vendor interoperability (ie, IANA-assigned types), and an 
extension code if we run out of room.

    Perhaps we also need to define the requirements for getting a vendor 
code or a standard type -- for instance, we might not want any 
individual to be able to get a vendor code, since they are limited; and 
the standard types would need some documentation, but perhaps not as 
widely reviewed as for a top-level option kind.

Andrew

Anantha Ramaiah (ananth) wrote:
> Hi,
>    I am just taking the liberty to post the first email on this mailing
> list. During our last call there was talk about the requirements of this
> TCP option. From our pov, the following would be the general
> requirements of the TCP option.
>
>
> Reason for TCP option :
>
> - A standard TCP option is needed because every vendor cannot have one
> option for the same purpose of auto-discovery and capability exchange.
> By standardizing the TCP option, firewalls etc., are aware of this
> option and problems can be avoided.
>
> Requirements of this TCP option :
>
> - There has to be a vendor ID (OUI) which would identify the specific
> vendor. This is needed because every vendors option format is going to
> be 
> different.
>
> - Already existing non-standardized option numbers (TCP option 33,
> riverbed's options no's) for doing auto discovery should not be
> allocated for this new TCP option. This is to prevent any confusion.
>
> - The TCP option needs to be variable length to permit multiple option
> formats since the option size may vary depending on the vendor.
>
> - This TCP option should be advocated for use only by middleboxes.
>
>
> My guess is that these requirements may be common for all the vendors or
> there may be some additional requirements not covered by this post. In
> either case we can continue the discussion and come to some conclusions.
>
> -Anantha
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