Re: [Spud] New Version Notification for draft-kuehlewind-spud-use-cases-00.txt

[Joe Touch <[e-mail]>]

On 7/8/2015 10:23 PM, Brian Trammell wrote:
> hi Joe, all,
...
>> One challenge is that IPv6 options are processed differently than IPv4 -
>> there's no way to "jump" straight into the transport header to find
>> ports (for port-based load balancing, e.g.).
> 
> Yep. If the option chain had a small and
> easily-hardware-determinable
> set of possible lengths -- which is the case for v4 options -- this
> would be easier (but still harder to handle on the fast path than the
> arrangements we're proposing here).

IPv4 options can be jumped over in one step using the IHL field. There's
no such field for IPv6 - routers have to walk the chain of headers one
by one.

>> I suspect you'll find that IP options are basically a non-starter except
>> for research purposes.
> 
> For the story on the v4 side, do you know of anything newer than
> Fonseca et al "IP Options are Not and Option" (tech report version at
> http://www.eecs.berkeley.edu/Pubs/TechRpts/2005/EECS-2005-24.pdf)? It's
> ten years old -- but given where the engineering effort has gone during
> that decade, I doubt strongly much has changed here.

Not much. Those old studies have been used in other WGs to drive
documents (IMO, unfortunately).

Joe