Re: [v6ops] Operational Implications of IPv6 Packets with Extension Headers - Load Balancer

[Tim Chown <[e-mail]>]

> On 29 Jul 2020, at 05:03, Brian E Carpenter <[e-mail]> wrote:
> 
> <snip>
> 
> All we can do here is write documents. So if
> the consensus is still what the standards track documents say, including
> Node Requirements, we have actually done our duty. And we have, in RFC8504:
> "All nodes SHOULD support the setting and use of the IPv6 Flow Label
> field as defined in the IPv6 Flow Label specification [RFC6437].
> Forwarding nodes such as routers and load distributors MUST NOT
> depend only on Flow Label values being uniformly distributed.  It is
> RECOMMENDED that source hosts support the flow label by setting the
> Flow Label field for all packets of a given flow to the same value
> chosen from an approximation to a discrete uniform distribution."
> 
> After that it really is up to vendors and operators to do what is best
> for them. If it takes ten years for all products to meet the Node
> Requirements, so be it.

Worth noting that RFC8504 is the third iteration of the IPv6 node requirements document, and what it says may and does change, partly as new RFCs are published, partly with more operational experience.

That said, the text above about flow label usage is the same in RFC8504 as it was in RFC6434, so the guidance has been the same for at least ten years or so.  The flow label wasn’t explicitly mentioned in the first node requirements document, RFC4294.

Tim