[mpls] Fw: on UDP encapsulation

[<[e-mail]>]

oops, typoed mpls list email address previously.
      On Saturday, 14 November 2015, 14:10, "[e-mail]" <[e-mail]> wrote:
   

 https://tools.ietf.org/html/rfc7510

I finally noticed that RFC7510, on MPLS in UDP encap, hasbeen published. Do take a look at all of section 3, whichlaboriously goes through the nuances of when to choosebetween UDP checksums, for safety, and turning them off,for speed, at slight risk. That section and the RFCs itrefers to are quite the complex read. And that's just onUDP checksums and whether to choose to turn them off. (Itgives dull security documents a run for their money.)
What's odd is that this is standards track, and the thirdoption, use standards-track UDP-Lite to provide checksumprotection of the UDP/IP pseudoheader to avoid zero-checksumport pollution on the host (on IPv4) or anywhere pollution(IPv6) is not mentioned as an alternative - particularly asUDP-Lite's partial payload coverage can cover the MPLS stack s well.
In some cases the Lite checksum is just a precomputed valueacross a generated header that doesn't change, at no encodecost and little decode cost, and within corporate privatenetworks the barriers to running UDP-Lite are less.
It's unfortunate that UDP-Lite is the ideal approach forthis, yet doesn't deserve consideration. Going back furtherin time, one might argue it's unfortunate that UDP-Lite waspushed to a separate protocol number, dooming it to oblivion.And, further back, that it was unfortunate that designers ofIPv6 thought leaving the pseudo-header demux check up toseparate transports that could then skip it, while insistingUDP always have its checksum on, which was always goingto be relaxed, was a good idea for consistent error-detectingdemux...
One might argue it's unfortunate. With the benefit of perfecthindsight, I favour 'bloody stupid' myself.
Does the IETF no longer work on UDP-Lite? Should UDP-Lite bemoved to Historic, along with SCTP and DCCP, becausethey're not TCP or UDP - even though delivery of tunnelledpayloads with demux protection is UDP-Lite's ideal application?
thanks
L.
Lloyd Woodhttp://about.me/lloydwood