[ovs-dev] [RFC PATCH v2 00/13] Add Network Service Header Support

[Elzur, Uri]

Jesse

So maybe it is just me, but I really don't get the similarity w IPv4 options. Both Geneve and NSH have TLV options. I have not seen a definition of the Geneve TLV format either (pls excuse me if I have missed it, and pls point me in the right direction).

Anyhow, I wonder how we move forward, we have multiple folks suggesting we can implement MD Type 1 first and see no bearing for OvS if we add MD TYPE 2 later. So is it a rough consensus? Multiple committers opine on this?

Thx

Uri (“Oo-Ree”)
C: 949-378-7568


-----Original Message-----
From: Jesse Gross [mailto:jesse at kernel.org] 
Sent: Thursday, July 14, 2016 8:40 AM
To: Elzur, Uri <uri.elzur at intel.com>
Cc: Thomas F Herbert <therbert at redhat.com>; Jiri Benc <jbenc at redhat.com>; dev at openvswitch.org; Manuel Buil <manuel.buil at ericsson.com>; su.wei at huawei.com; László Sürü <laszlo.suru at ericsson.com>; Paul Quinn (paulq) <paulq at cisco.com>; nick.tausanovitch at netronome.com
Subject: Re: [ovs-dev] [RFC PATCH v2 00/13] Add Network Service Header Support

On Wed, Jul 13, 2016 at 10:44 PM, Elzur, Uri <uri.elzur at intel.com> wrote:
> +1 on starting w MD Type = 1
>
> Not sure I understand the concern expressed with " implementations that don't implement TLVs will become deployed and  then when there is a use for them it's no longer possible." - why will it not be possible to add MD Type=2 later?

As I said, it's a classic problem with IP options. Classic enough that people frequently content that TLVs are not usable at all because they don't get implemented which then becomes a self fulfilling prophesy.

I think I've been extremely clear on this matter. I also think that I've been extremely consistent - I think I've said the same thing on every review of this patch series, so it should not exactly be a surprise. However, the bottom line is I want to see a complete implementation of the protocol and not a half measure that will catch people by surprise or limit future usage. That seems 100% reasonable to me.