All,

During the IPsecME interim meeting earlier this week, there was initial 
consensus from the participants that the WESP header should be aligned on an 8 
octet boundary for IPv6 in the following manner.

We will extend the WESP header by a 4 octet reserved field (all zeros) and use 
a new bit 'X' in the flags field to denote presence (or absence) of this 
alignment field.
This can be depicted as follows:

Existing WESP header:
0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |   HdrLen      |  TrailerLen   |V|V|E|  Rsvd   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Proposed change
0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |   HdrLen      |  TrailerLen   |V|V|E|X| Rsvd  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                 Reserved (zeros) for IPv6 alignment           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

If 'X' is set (value 1), the 4 octet reserved field is present (needed for 
IPv6). If 'X' is clear (value 0), the 4 octet reserved field is absent (needed 
for IPv4).

This comment was from AD review of the document and ticket #109 has been 
generated to track this item.

Any additional feedback?

Thanks,
- Ken
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