Re: ULE Extension Headers

[alain.ritoux@6wind.com]

Bernhard Collini-Nocker wrote:

> Hi,
>
> in my opionion it is a good idea to think about both the D bit and the E bit
> again.
> The D bit is useful in those cases where a destination MAC address is
> requested for filtering/addressing purposes. It could be a Type value as
> well, altough this adds duplicate Types wrt to functionality.
> The E bit could instead be a Type value as well and only if the format of
> the header fields of the Ext header is not the same it could become a
> different Ext header.
>
> The consequence of having no D and E bit but a Type value would be that the
> Type field could  be renamed to Next Header field, which it then essentially
> is. It would, however, require a different assigment strategy.

That is closed to what I proposed, and the pb I see, is that, with a
type/next header used to extension header, we have the same namespace
for both, and so the extension headers need to provide the "name" of the
next header (being and ext header or the payload itself). hence, each
extension header need 2 bytes to indicate what follows.
If we choose william strategy, the type field is linked to payload,
and extension header use a different name space, with only 1 byte to
identfy itself :
 - price : 1 bit in ULE header.
 - gain  : one byte per extension header.

Cheers.
Alain.
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Alain RITOUX
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