Re: [IPv6] FW: New Version Notification for draft-ls-6man-ipcomp-exclude-transport-layer-00.txt

[Nick Hilliard <[e-mail]>]

Shihang(Vincent) wrote on 24/10/2022 04:51:
> Hi 6MAN,
> I submitted a new draft about extensions to IPComp which compresses IP payload excluding transport layer and handles the out-of-order processing of compressed and un-compressed IP packet.
> 
> Looking forward to your review and comments.

couple of things on this draft:

- it's not clear that there is a need for a transport layer compression 
mechanism.  Application layer compression has been around for a long 
time and works well.

- as you identified in the draft, the mechanism proposed in this case 
will cause breakage:

>    [...]  Therefore, the
>    transport layer information such as source port and destination port
>    is compressed. [...]   If IPComp compressed those
>    transport layer information, the nodes along the packet's delivery
>    path can not obtain the source port and destination port.  Therefore
>    the IPComp is not compatible with the network functions requiring the
>    transport layer information which makes it harder to deploy.

Examples of things which require transport layer information: ECMP/LAG, 
filtering, control plane protection, etc.  If this information cannot be 
inspected, then this creates a serious regression for normal network 
function.

- in some cases, the output of a compression algorithm will be longer 
than the input. There is no indication in the draft how this would be 
handled.

Nick