[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: IPv6 Destination options extension header position.
<Setup deleted...>
> What is the right description?
The IPv6 RFC (1883) is the right description.
I remember now having a small exchange with someone else about this. I
decided not to pursue it because I figured the drawing in the AH draft was
intended to show possibilities, not real positioning. Apparently the AH
draft is confusing at least one person, and therefore needs to be clarified.
<SNIP!>
> Any comments?
"Destination" options (as opposed to hop-by-hop options) appear in TWO
places:
1.) Before the routing header, which affects "per-source-route-hop"
semantics.
2.) After AH, which affects "receiver-only" semantics.
I'm also sending this to the ipng to make sure I'm not forgetting something.
I'll show the original picture in the new AH draft, followed by my proposal
for a clearer illustration.
Here's the original one. Note the slight inaccuracy in destination options
placement...
> AFTER APPLYING AH
> ------------------------------------------------------------
> IPv6 | |hxh,rtg,frag| dest | | dest | | |
> |orig IP hdr |if present**| opt* | AH | opt* | TCP | Data |
> ------------------------------------------------------------
> |<---- authenticated except for mutable fields ----------->|
>
> * = if present, could be before AH, after AH, or both
> ** = hop by hop, routing, fragmentation headers
Here's my proposed replacement drawing:
AFTER APPLYING AH
------------------------------------------------------------
IPv6 | |hop-by-hop, dest*, | | dest | | |
|orig IP hdr |routing, frag. | AH | opt* | TCP | Data |
------------------------------------------------------------
|<---- authenticated except for mutable fields ----------->|
* = if present, could be before AH, after AH, or both
The above replacment text better illustrates (IMHO) AH placement in an IPv6
datagram than does the current text.
Dan
References: